Product Documentation
Virtuoso Visualization and Analysis XL User Guide
Product Version IC23.1, November 2023

4

Working with Graphs

The Virtuoso Visualization and Analysis XL graph window is a tool that you use to present the simulation data in a graphical format.

This chapter includes the following topics:

About the Graph Window

Virtuoso Visualization and Analysis XL graph window is a tool that you use to present simulation data in a graphical format. This helps you analyze simulation results. The ability to plot multiple graphs at a time enables you to compare simulation results. You can also customize your graphs by changing the background color and layout, and add markers and labels to annotate the graphs.

When you run the tool for the first time in a new session, a default graph is opened in a tab named Window 1. You can rename the window tab names by double-clicking the tab name or by setting the viva.graphFrame .cdsenv variable. You can also close the tabs that are not required. In a window, you can open multiple subwindows.

The graph window terminology is explained below:

In the graph window tool, you can also choose the assistants you want to display, which is defined by the selected workspace. The default workspace is Classic. For more information about Workspaces, see Working with Workspaces.

You can open the graph window from Virtuoso Visualization and Analysis XL or from the Analog Design Environment (ADE). If you open the graph Window from the Virtuoso Visualization and Analysis XL, you can work with previously saved simulation data. However, if you open the graph window from ADE, you work with the simulation data for the latest run. In both cases, when you select a signal, the graph window appears with the selected signal plotted.

Opening the Graph Window

You can use the following methods to open the graph window:

Opening the Graph Window from Virtuoso Visualization and Analysis XL

You can open the graph window in either SKILL mode from the Virtuoso Visualization and Analysis XL tool. By default, the graph window is opened in the SKILL mode.

Perform the following steps to open the graph window from Virtuoso Visualization and Analysis XL tool:

If you type only viva & in the terminal window, the default mode is SKILL.

For information about how to create a graph in the graph window, see Creating a Graph.

Opening the Graph Window from Virtuoso in Stand-Alone Mode

To open the graph window from Virtuoso in the stand-alone mode, perform the following step:

Opening the Graph Window from ADE

You can run simulations in ADE and plot the simulation results in the Virtuoso Visualization and Analysis XL graph window. The Virtuoso Visualization and Analysis XL graph window supports simulation analysis types such as transient, AC, DC, and RF measurement.

To open the graph from ADE, do the following:

In ADE Assembler, after you run the simulation, you can specify whether you want to save the simulation results to a results database or plot the simulation results in a window. Each item that appears on the Outputs Setup tab has a Plot check box and a Save check box. Select the Plot check box to display the selected outputs in the window after the simulation run is complete. Select the Save check box to save the selected output results to a results database.

Notice the following when you open the window by using ADE:

Graphical User Interface

The Virtuoso Visualization and Analysis XL window user interface consists of a menu bar, toolbars, dockable assistants, and subwindows that are displayed according to the selected workspace. You can hide and show these GUI components based on the workspace you select. By default, the assistant panes appear on the left and the graphs appear in the display area on the right. When you plot a signal in the new window, a new window tab is created. You can click the tab to view the required graph and can rename window tabs by double-clicking the tab name. You can also close the window tabs that are not required.

In a window, you can open multiple subwindows. The subwindows includes all properties of a graph window and can be further divided into subwindows.

By default, the window background is black. If required, you can set the background to white. For more information, see Setting the Graph Colors.

The Virtuoso Visualization and Analysis XL window includes the following elements:

Menu Bar

The menu bar has the following menus:

File

The table below lists the File menu commands.

Command Description

Open Results

Opens the Select Waveform Database form that you can use to select a results database. This form displays the current results directory.

Close Results

Closes the selected results directory in the Results Browser.

New Window

Opens a new graph window in the display area. This creates a new window tab.

New Subwindow

Opens a new subwindow in the active window. For more information, see Working with Subwindows.

Load Window

Loads a file containing a graph in the active window. For more information, see Loading a Graph.

Save Window

Saves the graph in the active window to a file. For more information, see Saving a Graph.

Save Window As

Saves a copy of the graph in the active window to a file. For more information, see Saving a Graph.

Window Properties

Changes the background color of all the subwindows in the active window.

Reload

Updates data for all the traces in the active subwindow or all the subwindows. For more information, see Reloading Graphs.

Create Maestro Plotting Template

Saves a graph window as a plotting template after the simulation is run and results are plotted. The saved plotting template can be used to plot waveform outputs in the specified format for next simulation runs. All the formatting, markers, layout changes, and other interface changes will be retained as specified in the plotting template. For more information, see Working with Plotting Templates in Virtuoso ADE Explorer User Guide.

The video ViVA XL - Plotting Templates demonstrates how you can create plotting templates.

Print

Sends the graph to a printer or saves the graph in a PDF format. For more information, see Printing Graphs.

Save Image

Saves the graph displayed in the active window as an image file. For more information, see Printing Graphs.

Close Window

Closes the active window. If there is only one open window, the Close command exits the tool.

Close All Windows

Closes all windows and exits the tool.

Edit

The table below lists the Edit menu commands.

Command Description

Undo

Undoes the most recent action in the active window.

Redo

Redoes the most recent action in the active window.

Cut

Moves the selected graph objects to the clipboard.

Copy

Copies the selected graph objects to the clipboard.

Paste

Pastes the contents of the clipboard to the selected location.

Delete

Deletes selected objects, such as labels, markers, traces, or graphs.

If no object is selected, a message appears confirming the deletion of the active subwindow.

If only one window is open, the Delete command is not available.

Delete All

Deletes all the objects and graphs in the active window. If only one window is open, the Delete All command is not available.

Properties

Enables you to modify the properties of the recently selected graph object. By default, the graph properties form appears if you do not select any object.

Multi-Graph Properties

Enables you to modify the properties of all the windows in one step.
You can cut, copy, and paste between multiple Virtuoso Visualization and Analysis XL sessions within the same Virtuoso process. You can move entire graphs in this manner, or individual traces along with the associated markers. The clipboard contents are retained even when a Virtuoso Visualization and Analysis XL session is closed and another new session is invoked from same Virtuoso process.

View

The table below lists the View menu commands.

Command Description

ZoomIn by 2

Zooms in the graph by a factor of two.

ZoomOut by 2

Zooms out the graph by a factor of two.

Zoom to End

Zooms the trace to the end of the graph.

Fit

Returns the graph to the original size to fit data in the window. This command works for both rectangular and circular graphs.

Previous

Enables you to view the graph at the magnification specified before the last zoom in or zoom out command was run. You can use this option when you zoom in or out a graph multiple times.

Next

Undoes the Previous command. You can use this option when you zoom in or out a graph multiple times.

The Next and Previous commands help you navigate through the zoom and the pan stack.

Fit Trace

Returns the selected trace to its original size to fit in the window. When you select this option, the X-axis zoom of all the strips is displayed in the original size, where as the Y-axis zoom of only selected axis is changed. This command works for both rectangular and circular graphs.

Fit Visible Traces

Fits all the traces visible on the graph to their original size.

Fit Y to Visible X

Fits the visible part of the trace to Y-axis. This command finds the minimum and maximum Y-axis values that are visible in a strip and then performs a Y-axis zoom of those Y values. This command works only for the zoomed-in graphs.

Fit Y to Visible X all Strips

Fits the visible part of the traces to Y-axis for all the strips displayed in the active graph. This command finds the minimum and maximum Y-axis values that are visible in each strip and then performs a Y-axis zoom of those Y values. This command works only for the zoomed-in traces.

Fit Smith

Returns the selected Smith chart to its original size so that it fits into the window. This command is available only for the circular graphs.

Graph

The table below lists the Graph menu commands.

Command Description

Layout

Specifies how subwindows are displayed in the active window. You can select the layout as Auto, Vertical, Horizontal, and Card. For more information about graph layouts, see Setting the Graph Colors.

Link

Links rectangular graphs in the subwindows of a graph window.

For more information, see Linking Graphs in Subwindows.

Add Label

Adds a label to the graph. For more information about graph labels, see Working with Graph Labels.

Lock

Locks the graph from any data updates. For more information, see Locking Graphs.

Split Current Strip

Splits the graph into as many strips as there are traces and displays each trace in the graph in a separate strip. You can also select this command from the Strip toolbar. For more information, see Working with Strips.

Split All Strips

Splits the traces in all the strips in the graph into individual strips. This is useful if the graph contains more than one strip.

Plot to New Strip

Plots the selected trace in a new strip.

Combine All Analog Traces

Combines all the individual analog traces into a single graph. For more information, see Combining Graph Strips.

Filter By Sweep Var

Displays the traces for the selected sweep variable range.

Redraw

Refreshes the graph and plots the updated graph in the same window. This command also refreshes the trace legend area.

Toggle Major and Minor Grids

Displays or hides the major and minor grids in the selected axis. Alternatively, you can use bindkey G to toggle between the major and minor grids. To use this bindkey, ensure that an axis is selected.

Properties

Sets the graph properties. You can set the general graph properties as well as the strip properties in the Graph Properties form that appears when you select Properties. For more information, see Editing Graph Properties.

Axis

The table below lists the Axis menu commands.

These commands are available only if you select an axis in the graph.

Command Description

Major Grids

Displays the major grid lines for the selected X or Y axis.

Minor Grids

Displays the minor grid lines for the selected X or Y axis.

Log

Displays the logarithmic scale for the selected X or Y axis.

Select Attached Traces

Selects all the traces that are attached to the axis you select.

Y vs Y

Displays the YvsY plot of the selected axis in the window. This command is available only for the sweep data. For more information, see Plotting YvsY Graph.

Swap Sweep Var

Enables you to swap sweep variables. This command is available only if you select the sweep data. For more information, see Swapping Sweep Variables.

Properties

Sets the attributes for the selected X or Y axis. For more information, see Editing Graph Axis Attributes.

Trace

The table below lists the Trace menu commands.

Command Description

Symbols On

Displays symbols on individual data points for the selected trace.

This command is available only if you select one or multiple trace in the graph.

Select by Family

Selects all the traces with the parametric sweep data that belong to a family. When you enable this command, and select a trace in the family, all traces that belong to the same family are selected.

Strip by Family

Displays traces that belong to the same family in a single strip when you split traces into strips. If more than one family of traces are present, each family is displayed in a separate strip.

Fit Trace

Returns the selected trace to its original size to fit in the window. When you select this option, the X-axis zoom of all the strips is displayed in the original size, where as the Y-axis zoom of only selected axis is changed.

Fit Y to Visible X

Fits the visible part of the trace to Y-axis. This command finds the minimum and maximum Y-axis values that are visible in a strip and then performs a Y-axis zoom of those Y values. This command works only for the zoomed-in graphs.

Disable Reload

Disables the reloading of a trace by locking the database context and the trace is not reloaded with new data when the in-context results directory is changed. For more information, see Disabling Trace Reload.

Select All

Selects all traces in a graph.

Delete All

Deletes all the traces displayed in the active graph. The independent axis, window title, and pan bar are not deleted.

Move to

Moves the selected trace to the following locations:

  • New Window—Moves the selected trace to a new window.
  • New Subwindow—Moves the selected trace to a new subwindow.
  • New Strip—Moves the selected traces to a new strip.

Copy to

Copies the selected trace to the following locations:

  • New Window—Copies the selected trace to a new window.
  • New Subwindow—Copies the selected trace to a new graph subwindow.
  • New Strip—Copies the selected trace to a new graph strip.

Bus

This command has the following options:

Create—Creates a bus from the selected digital traces. For more information, see Creating a Bus.

Expand—Expands a bus to its component signals. For more information, see Expanding a Bus.

This option is available only if you select a digital bus.

Collapse—Collapses the bus components to display the complete bus.

This option is available only if you expand the bus.

Export

Exports the selected trace in the active window in a variety of formats and later loads it in the required application.

Properties

Enables you to specify properties of the selected trace. For more information, see Setting Trace Properties.

This option is available only if you select a trace in the graph.

Marker

The table below lists the Marker menu commands.

Command Description

Tracking Cursor

Enables or disables the tracking cursor for the graph. When you move the mouse pointer on a trace or on a graph object, the tracking cursor displays the trace name and the graph object information.

Snap Tracking Cursor

Snaps the tracking cursor to the simulation points. When you move the mouse pointer on the simulation points on a trace, the tracking cursor displays the trace name and the graph object information

Create Marker

Creates a new marker for the trace in the graph. For more information, see Adding Markers.

Create Delta Marker

Creates a new delta marker. To create a delta marker, you need to place a point marker on the trace or select an existing point marker. For more information, see Adding AB Marker.

Show Delta Child Labels

Shows or hides marker labels for the delta markers.

Delete all

Deletes all the markers displayed in the active subwindow or a graph.

Export Table

Exports the selected marker information in a given format.

Properties

Specifies the properties for a marker. For more information, see Setting Marker Properties.

This command is available only if you select a marker on the graph.

Measurement

The table below lists the Measurement menu commands.

Command Description

Eye Diagram

Plots an eye diagram for the selected graph. The eye diagram divides the waveforms into fixed time periods, which are then superimposed on each other. When you select this command, the Eye Diagram assistant appears. For more information, see Eye Diagram Assistant.

Spectrum

Plots a spectrum for the selected graph. When you select this command, the Spectrum assistant appears. For more information, see Spectrum Assistant.

Analog to Digital

Converts an analog signal into a corresponding digital signal. For more information, see Converting a Digital Signal to an Analog Signal.

This command is available only in the SKILL mode.

Digital to Analog

Converts a digital signal into a corresponding analog signal. For more information, see Converting an Analog Signal into a Digital Signal.

This command is available only in the SKILL mode.

Derived Plots

Generates the derived plots that are the risetime or falltime waveforms derived from the entire set of edges and plotted against time. For more information, see Generating Derived Plots.

Histogram

Generates the histogram plot directly on a graph. For more information, see Plotting Histogram.

Transient Measurement

Opens the Transient Measurement assistant that displays the calculated measurements for the transient markers on specific edges. For more information, see Transient Measurement Assistant.

Tools

The table below lists the Tools menu commands.

Command Description

Calculator

Opens the Virtuoso Visualization and Analysis XL Calculator window.

For detailed information about working with the Calculator, see Chapter 5, “Working with the Calculator.”

Window

The table below lists the Window menu commands.

Command Description

Assistants

Displays or hides the selected assistant panes. The available assistants are—Spectrum, Browser, Marker Toolbox, Eye Diagram, Direct Measurements, Horiz Marker Table, Trace Info, Vert Marker Table, Customize Trace Groups, and Subwindows. For more information, see Assistants.

For more information about assistant panes, see the Virtuoso Studio Design Environment User Guide.

Workspaces

Displays, saves, loads, and configures the selected workspace. The available workspaces are—Basic, Browser, Classic, and MarkerTable. For more information, see Working with Workspaces.

For more information about workspaces, see “Getting Started with Workspaces” in Virtuoso Studio Design Environment User Guide.

Toolbars

Displays or hides the selected toolbars. The available toolbars are—Edit, View, Graph, Calculator, Snap, Marker, Strip, Measurement, Axis, and Workspaces. For more information about toolbars, see Toolbars.

Browser

The table below lists the Browser menu commands.

Command Description

Results

Includes the following Results Browser commands:

  • Open Results—Opens the results directory in the Results Browser. When you select this command, the Select Waveform Database form appears that you can use to select the results database.
  • Export—Exports a selected signal from the Results Browser.
  • Close Results—Closes the results directory in the Results Browser. This is available only if you select a results directory in the Results Browser.
  • Reload—Reloads the results directory that was last open into the Results Browser.
  • Set Context—Enables you to set the database in-context results directory, which you use to plot signals in the Results Browser. The first results directory that you load in the Results Browser is set as the in-context results directory.

Options

Includes the following commands:

  • Graph Modifier—Includes commands that you can use to specify how the graph is plotted:
    • Magnitude—Plots magnitude versus frequency.
    • Phase—Plots phase versus frequency.
    • WPhase—Plots wrapped phase versus frequency.
    • Real—Plots real value of the dependent data versus frequency.
    • Imaginary—Plots imaginary value of the dependent data versus frequency.
    • dB10—Plots dB10 value of the dependent data versus frequency.
    • dB20—Plots dB20 value of the dependent data versus frequency.
    • dBm—Plots mili dB value of the dependent data versus frequency.
  • Plot Style—Enables you to select the mode in which a graph is to be plotted. The signal in the graph can be plotted in the following modes:
      • Append—Adds the signal to the selected graph.
  • Select Data—Sets the sweep range for the data. When you select this command, the Set Sweep Ranges form appears. This command is available only if the dataset selected in the Results Browser supports ranging, such as the PSF transient dataset, or contains parametric sweep data.

  • Enable Fast Waveforms—Enables the fast waveform format in which the Virtuoso Visualization and Analysis XL tool can render extremely large datasets within seconds.

Help

The table below lists the Help menu commands.

Command Description

Search

A text field that lets you enter a search string. Press Enter to view the search results.

Do not enclose the search string in double quotes.

User Guide

Opens Virtuoso Visualization and Analysis XL User Guide (at the section that provides information about using CIW) in Cadence Help.

What’s New

Opens the Virtuoso What’s New document in Cadence Help.

Known Problems and Solutions

Opens the Virtuoso Known Problems and Solutions document in Cadence Help.

Virtuoso Documentation Library

Opens the Cadence Help home page, which provides quick access links to the following local and online resources:

  • What’s New
  • Video Demos and Tutorials
  • Featured Content
  • Known Problems and Solutions
  • Other web resources

Virtuoso Video Library

Opens the Video Library page available on Cadence Online Support (COS). This page lists the videos available for various Virtuoso products.

You must have a COS account to access the content available on COS.
Contact your IT support to ensure that the Internet ports required for video playback are enabled.

Virtuoso Rapid Adoption Kits

Opens the Rapid Adoption Kits page on COS. This page lists Rapid Adoption Kits (RAKs) available for various Virtuoso products.

Virtuoso Learning Map

Lists domain-specific training available on Cadence Training Services.

Cadence Training Services learning maps provide a comprehensive visual overview of the learning opportunities for Cadence customers. They provide recommended course flows as well as tool experience and knowledge levels to guide customers through a complete learning plan.

Virtuoso Custom IC Community

Opens the Virtuoso Custom IC Community web page. This page provides access to the latest blogs and discussion threads on various Virtuoso products and design topics, information about software downloads and support and training, and other related information. You too can contribute to the community forum by creating a Cadence account. This gives you additional benefits such as alerts about topics of interest and access to online webinars.

Cadence Online Support

Opens COS, which you can use to access information about Cadence products, documentation, videos, RAKs, application notes, troubleshooting information, alerts, and so on. Improvements are regularly made to COS to make it convenient for you to look up the information you want. We recommend that you bookmark this web site and use it as your first point of reference for any Virtuoso-related information.

You can also access COS by clicking the Cadence logo available in the upper-right banner in each Virtuoso window.

Cadence Training

Opens the Cadence training web page. You can find on this page information about the training courses available in different regions. Information is available about both classroom and online courses.

Cadence Community

Opens the Cadence Community web page. This page provides access to the latest blogs and discussion threads on various Cadence products and solutions, and EDA Industry Insights. You too can contribute to the community forum by creating a Cadence account. This gives you additional benefits such as alerts about topics of interest and access to online webinars.

Cadence OS Platform Support

Provides information about the current Cadence software releases and the supported platforms.

Contact Us

Opens the Cadence Customer Support web page, which provides customer support contact information for different regions.

Cadence Home

Opens the Cadence corporate web site.

About Virtuoso

Displays Virtuoso Studio Design Environment version information.

Toolbars

Do one of the following to show or hide toolbars in Virtuoso Visualization and Analysis XL:

The Virtuoso Visualization and Analysis XL has the following toolbars:

Mouse Bar

Displays at the bottom of the Virtuoso Visualization and Analysis XL window to indicate the left, middle, and right mouse movements.

Edit Toolbar

The Edit toolbar contains the following buttons:

For information about these toolbar buttons, refer to the Edit menu commands.

View Toolbar

The View toolbar contains the following buttons:

For information about these toolbar buttons, refer to the View menu commands.

Layout Toolbar

Displays the Layout button to specify the layout of the subwindows in an active window. For more information, see Specifying the Subwindows Layout.

Graph Toolbar

The Graph toolbar contains the following icons:

Calculator Toolbar

Displays the Calculator button to send the selected trace to the Calculator Buffer.

Snap Toolbar

The Snap toolbar contains the following buttons:

This toolbar is available for both analog and digital signals and the toolbar options work if you select a marker. For more information, see Snapping Markers and Snapping Markers on Circular Graphs

Marker Toolbar

The Marker toolbar contains the following buttons:

Measurement Toolbar

The Measumerent toolbar includes the following button:

File Toolbar

The File toolbar has the following buttons:

Strip Toolbar

The Strip toolbar contains the following buttons:

Axis Toolbar

You can use the Axis toolbar to turn on or turn off the grid from a graph.

Alternatively, you can do the following:

Workspace Toolbar

You can use the Workspace toolbar to work with the available workspaces.

For more information about workspaces, see Working with Workspaces.

Status Bar

The status bar displayed at the bottom of the window displays the following information:

Assistants

The Virtuoso Visualization and Analysis XL includes the following assistants:

For detailed information about assistants, see Working With Assistants.

Creating a Graph

You can create a graph by plotting a signal selected in the Results Browser in the window. To group similar graphs or to compare two graphs, you can open multiple subwindows in a window.

To create a graph, perform the following steps:

  1. In the Results Browser, open a results directory and select the signal you want to plot.
  2. To select the window where you want to plot the signal, do one of the following:
    • Choose Browser – Options – Plot Style.

    The Plot Style can be of the following types:
      • Append—Adds the waveform expressions or signals to the active window or subwindow. If the data in the selected subwindow is incompatible with the waveform expression or signal being appended, this waveform expression or signal is plotted in the next compatible window. If none of the existing subwindows are compatible, the waveform expression or signal is plotted in a new subwindow. The incompatible data refers to the waveforms generated from different analyses, such as AC, transient, and so on. In addition, if the X-axis of active subwindow is different from the X-axis of the waveform or signal being appended, the waveform is plotted in a new subwindow.
      • Replace—Replaces the graph in the active window with a new graph.
      • New Window—Plots the signals in a new window. When you create a graph for the first time, it is always displayed in a new window.
      • New Subwindow—Plots the graph in a new subwindow within the active window.
  3. After you specify the destination graph, do one of the following to plot the signal:
    • Double-click the signal.
    • Right-click the signal and select the Plot Signal option.
    • Click the button in the Results Browser.

    The graph appears in the selected destination window.

Dragging Graphs Across Multiple Virtuoso Visualization and Analysis XL Sessions

You can drag traces and graphs across different Virtuoso Visualization and Analysis XL opened within the same Virtuoso session. To copy a trace or a group of traces from one Virtuoso Visualization and Analysis XL session to another, select the traces by using the Ctrl key and then drag and drop the selected traces in the destination window of the another session.

You cannot drag traces across two Virtuoso Visualization and Analysis XL sessions that are opened from within different Virtuoso processes. In this case, you can export or import graph files to move traces from one session to another. For more information about how to export a trace, see Exporting a Trace.

While dragging, only the waveform data is copied to the subwindow of the another session. The drag operation does not save trace properties, such as color, linestyle, symbol, the markers and the Y-axis modifiers, such as dB10, dB20, phase.

Limitations

Dragging is not supported in the following cases:

Working with Subwindows

A window can be divided into subwindows that displays waveforms in individual mini-graphs. Each subwindow can be set to show the rectangular, tabular, polar, impedance, admittance or immittance plots. You can open multiple empty subwindows in a graph window tab. When you open Virtuoso Visualization and Analysis XL for the first time with no results database open, by default, a graph window tab is opened with a blank subwindow showing the subwindow number as 1. You can open multiple empty subwindows and choose the graph type for them.

You can also customize these subwindows according to your requirements. The customizations can include – resizing of subwindows, combining subwindows with other existing subwindows, dragging subwindows to any location, merging subwindows, and swapping subwindows with other subwindows. You can also specify the layout in which subwindows appear in a graph window.

The figure below shows an example of the customized subwindows in a window.

By default, subwindows are created based on a non-overlapping grid structure. You can also expand subwindows into any empty space to cover multiple grids together.

This section includes the following topics:

You can also read the Virtuosity: New Flexible Subwindows blog for more information about the subwindows.

Creating a New Subwindow

To create a new empty subwindow, do one of the following:

Specifying the Subwindows Layout

A window can have several subwindows that are displayed in the specified layout. When the subwindows contain plots, do one of the following to specify a layout for the subwindows:

The following buttons for subwindows layout are displayed:

Customizing a Subwindow

By default, the subwindows are displayed in the Auto mode. To specify your own layout to customize the subwindows in a graph window:

The first subwindow to appear at the top left is the active subwindow. When you select a signal for plotting in the Results Browser, it is plotted in the active subwindow. By default, this subwindow plots only rectangular graphs. If you choose to plot a circular graph, its rectangular equivalent is displayed in this subwindow.

To plot the graphs in other subwindows:

Selecting the Graph Type for Blank Subwindows

To select the graph type for blank subwindows:

Important Points to Note

Deleting a Subwindow

To delete a subwindow, do one of the following:

Important points to note:

Copying a Subwindow

To copy a subwindow to a new window or a subwindow:

Resizing a Subwindow

To resize a subwindow, place the pointer on the subwindow. The resize box with drag handle appears. Drag these blue dots to resize the subwindow in the horizontal or vertical directions.

The drag handle is displayed in gray to indicate that it is disabled and you cannot drag the subwindows in that direction.

Moving a Subwindow

To move the graph plotted in a subwindow to another subwindow, drag the subwindow using the pointer and place it in the desired subwindow or an empty subwindow.

Changing the Subwindow Properties

To change the properties of a particular subwindow:

To change the attributes of all the windows and subwindows together:

Changing the Background Color of Subwindows

By default, all the subwindows are displayed with a black background. To change the background color of the subwindows:

The following figures show the background color changed to white.

With Gradient:

Without Gradient:

Linking Graphs in Subwindows

You can link graphs in subwindows to automatically set the same minimum and maximum values of x and y axes for the linked graphs. You can link only those subwindows of a graph window that share the same units for x and y axes.

You can link only rectangular graphs.

To link graphs in the subwindows:

  1. Select the subwindow that you want to link and choose Graph – Link – Add.
  2. Repeat the first step for all the subwindows that you want to link.
    To link all graphs in the subwindows of a graph window, first select any subwindow and choose Graph – Link – All Graphs on Page.
    A link icon is displayed at the top-left corner of each linked subwindow. Note that the rectangular graphs in the subwindows 1, 2, and 3 have the same unit us for x axis and voltage for y axis. Also, the graph in the subwindow 4 is not linked because it is a polar graph.
    Zoom operations on x and y axes performed on a subwindow are applied to all the linked subwindows.

Unlinking Graphs in Subwindows

To unlink graphs in the subwindows of a graph window:

Linking Axes in Subwindows

By default, both x and y axes of graphs are linked when you link graphs in subwindows. However, you can choose which axes you want to selectively link.

To selectively link axes:

  1. From the menu bar of Virtuoso Visualization and Analysis XL, choose Graph – Link – Link Options.
    The Link Options form opens.
  2. Select the Link Dependent (Y) Axes check box to link only y axes in the linked graphs.
    All y axes that have the same units are linked.
  3. Select the Link Independent (X) Axes check box to link only x axes in the linked graphs.
    All x axes that have the same units are linked.
  4. Select the Only Link Axes with These Units check box and specify the base units of the axes in the text field if you want to link only axes with the specified base units. You can specify multiple base units as a list of comma-separated values. For example, V,A,Hz,s.
    This option is helpful when there are multiple units available for both dependent and independent axes and you want to link only the axes which have specific units.

Example

Consider the following graph window in which four waveforms sig1, sig2, sig3, and sig4 are plotted in the subwindows 1, 2, 3, and 4, respectively.

Note that all subwindows of the graph window are linked together.

The following table shows how dependent and independent axes of subwindows 1, 2, 3, and 4 are linked when different combinations of options are selected in the Link Options form.

Link Dependent (Y) Axes Link Independent (X) Axes Only Link Axes with These Units Result

Selected

Selected

Not selected
  • y axes of subwindows 1 and 2 are linked together.
  • y axes of subwindows 3 and 4 are linked together.
  • x axes of subwindows 1 and 3 are linked together.
  • x axes of subwindows 2 and 4 are linked together.

Selected

Not Selected

Not Selected
  • y axes of subwindows 1 and 2 are linked together because they have the same base unit V for their y axes.
  • y axes of subwindows 3 and 4 are linked together because they have the same base unit A for their y axes.

Selected

Not selected

Selected and base unit A is specified in the text field.

Only y axes of subwindows 3 and 4 are linked together because only they have base unit A for their y axes.

Selected

Not selected

Selected and base unit V is specified in the text field.

Only y axes of subwindows 1 and 2 are linked together because only they have base unit V for their y axes.

Selected

Not selected

Selected and base units V,A are specified in the text field.
  • y axes of subwindows 1 and 2 are linked together because they have the same base unit V for their y axes.
  • y axes of subwindows 3 and 4 are linked together because they have the same base unit A for their y axes.

Not selected

Selected

Not selected
  • x axes of subwindows 1 and 3 are linked together because they have the same base unit s for their x axes.
  • x axes of subwindows 2 and 4 are linked together because they have the same base unit Hz for their x axes.

Not selected

Selected

Selected and base unit s is specified in the text field.

Only x axes of subwindows 1 and 3 are linked together because only they have base unit s for their x axes.

Not selected

Selected

Selected and base unit Hz is specified in the text field.

Only x axes of subwindows 2 and 4 are linked together because only they have base unit Hz for their x axes.

Not selected

Selected

Selected and base units s,Hz are specified in the text field.
  • x axes of subwindows 1 and 3 are linked together because they have the same base unit s for their x axes.
  • x axes of subwindows 2 and 4 are linked together because they have the same base unit Hz for their x axes.

Related Topics

linkDepAxes

linkIndepAxes

useLinkAxesUnitFilter

linkAxesUnitFilterSet

Customizing a Graph

After you have created a graph, you can customize it to analyze the graph data.

This section contains the following topics:

Determining the Active Window

The active window tab appears white and the inactive window tabs appear gray. When you click a window tab, that window becomes active and the tab color changes to white.

The video Using Subwindows in Qt Graph demonstrates how to change the graph layout and how to plot signals in different subwindows.

Setting the Graph Colors

The default color scheme for graphs is determined by the viva.graphFrame background variables in the .cdsenv file. The default color scheme is as follows:

To change the background color of a window, do the following:

  1. In the window, choose File – Window Properties.
    The Window Properties form appears.
  2. In this form:
    1. Click the Background button to set the background color of the selected window.
    2. Select the Use Gradient check box to add a gradient to the background, which means the background color fades at the bottom of the graph. By default, this check box is disabled.

You can also change the background color of a graph by setting the following environment variable:

envSetVal("viva.graphFrame" "background" 'string "<color>")
When you change the background color of the graph, Virtuoso Visualization and Analysis XL automatically adjusts the color contrast of various graph objects, such as traces, markers, labels, and tracking cursor to make them clearly visible on the graph.

Renaming and Closing Window

To rename a window, double-click the window tab and type the new name.

To close the window, close the window tab by clicking the cross button.

Handling Graph Objects

This section describes how you can select and delete a graph or its components, such as traces, axes, markers, and labels.

Selecting Objects

Click the graph or its component, such as trace, marker, or label, to select it. You can select multiple objects by holding down the Ctrl key while you click the required graph objects.

Deleting Objects

You can delete the objects, such as graphs, labels, markers, legends, and traces. You can also delete a window or a subwindow.

To delete an object, do the following:

  1. Select the object you want to delete.
  2. Choose Edit – Delete, or press the Delete key.
    The object selected in the window is deleted.

To delete all objects, select an object or a subwindow and do one of the following:

To delete all markers in a window, choose Marker – Delete All or press Ctrl+E.

To delete all traces in a window, choose Trace – Delete All or press Shift+E.

Panning and Zooming Graphs

You can pan and zoom a graph by using the pan bar and scroll bar displayed in the graph window.

This section covers the following topics:

Panning a Graph

You can use the pan bar located at the top of the window to pan a graph. When you plot a signal in the graph, the width of the pan bar is adjusted so that the entire graph is visible. Resize the pan bar by dragging either end of the pan bar inward to view the required portion of a graph. The selected portion of the graph is zoomed in to display greater detail. When the size of the pan bar is less than maximum, drag the pan bar to the left or right to view portions of the graph that are currently outside the display area. You can also click anywhere in the pan bar area to move the pan bar to that location.

Alternatively, to pan a graph, do one of the following:

You can hide the pan bar by de-selecting the Display zoom bar check box in Graph Options tab of the Graph Properties form.

Zooming a Graph

The Virtuoso Visualization and Analysis XL tool supports multiple zooming operations.

To zoom in or out a graph, choose one of the following options from the View menu or click the relevant button on the zoom toolbar.

Alternatively, to pan and zoom in or out a graph, do the following:

Zooming In a Trace Along X- and Y-Axis

To zoom in a trace along X- and Y-axis, hold down the mouse button and drag the pointer to select the area on the graph that you want to zoom in. When you release the mouse button, the area you selected is zoomed in.

To zoom in the trace along one axis, do the following:

  1. Press bindkey X to zoom in the graph along the X-axis or press bindkey Y to zoom in the graph along the Y-axis.
  2. Hold down the right mouse button and drag the pointer to select the graph area that you want to zoom in.
    After you release the mouse button, the zoom is complete and the right mouse button zoom is reset to XY zoom, which means you can now zoom in or out the graph along both the axes.
You cannot zoom in the graph by using the left mouse button. Also, ensure that you zoom the area toward the right of the Y-axis; otherwise, a shortcut menu appears.
If you have multiple strips in a window that you want to zoom in, place the pointer on the left or right edges of the strip container to start the zoom.

Panning And Zooming Graph With Mouse

To pan a graph with the help of mouse, perform the following steps:

  1. Hold down the Ctrl and Alt keys simultaneously. Notice that the mouse pointer is changed to a hand symbol, which indicates that you pan the graph now.
  2. Drag the mouse pointer to pan the graph in left or right direction.
If a graph includes multiple strips, the panning procedure is performed on all the strips at the same time.

To zoom in or out a graph or a strip in Y direction with the help of mouse, do the following:

To zoom in or out all the strips in a graph in X direction, do the following:

When you move the wheel button upward, the selected strip is zoomed in, and if you move the wheel button downward, the selected strip is zoomed out.

To zoom in in or out all the strips in a graph in both X and Y direction, do the following:

The video Panning and Zooming Qt Graph demonstrates how you can pan and zoom the Qt Graph.
The zoom operations that you perform on the graph are added to a zoom stack and you can switch between the various zoom levels by selecting zoom commands in the View toolbar. The zoom stack can store maximum of 100 zoom operations.

Consider the scenario in which multiple traces are plotted in different strips in the graph window and the graph window size is small such that scrollbars appear on the graph. Now, if you zoom in the trace in one of these strips a few times and then use the mouse scroll wheel to zoom out the within that strip, the trace in the strip zooms out until it is fit and after that mouse scroll wheel starts scrolling through the outer scrollbar of the graph window.

Editing Graph Properties

To set the properties of a graph, do one of the following:

A red button is displayed with each form field in the properties form for graph and graph objects, which acts as a toggle switch. By default all the form fields are opened in the edit mode. If you click this button, you cannot edit the form fields.

Editing the Graph Title

To edit a graph title, double-click anywhere in the graph title area. The mouse pointer changes into a cursor. You can now delete the existing grapg title and type the new title. While editing, you can also use the keyboard arrow, Home, or End keys.

Setting Properties for Multiple Graphs

Virtuoso Visualization and Analysis XL helps you change the properties of graphs plotted in different windows in a single step. This is useful when you open multiple graphs in several windows and want to apply the same settings in all the opened graphs.

To set the properties of multiple graphs plotted in different windows,

This form includes the following fields that you can set for all the graphs:

Working with Graph Axis

This section covers the following sections to describe how to use X- and Y-axis while plotting and analyzing signals in a graph.

Editing Graph Axis Attributes

The X-axis attributes set the attributes for the X-axis. The X-axis attributes provide a mechanism to create YvsY plots.

Eye diagrams can also be plotted from the Calculator, while a limited version of YvsY plot is available from the Results Browser.

The default graph attributes are controlled by the values assigned to variables in the .cdsenv file. For more information, see Appendix A, “Virtuoso Visualization and Analysis XL Tool Environment Variables.”

You can edit the attributes of the axes by doing one of the following:

Changing Digital Dependent Axis Properties

To change the properties of the digital dependent axis, right-click the trace and choose Digital Axis Properties. The Digital Dependent Axis Properties form appears. You can use this form to change the axis font and foreground color by setting the Font/Color field.

Changing Axes Scale to Logarithmic

To display the dependent or independent axes scale in logarithmic values, do one of the following:

Displaying X-Axis Labels in String Format

If you select the X-axis variable as model file or Corner while plotting the results for a simulation run in ADE XL for sweep data, the labels on X-axis are displayed in string format.

In the figure below, you can see the simulation results plotted in the graph window. The sweep variables for this simulation are—VDD, modelFiles, and temperature. This simulation also contains corner values. After you run the simulation, the different outputs are listed in the Output section of ADE XL. When you plot all the outputs, the waveforms are plotted in individual subwindows. See the figure below. Notice that the plots shown in the figure below have temperature as the sweep variable on X-axis. You can change the X-axis variable to modelFiles, VDD, or Corner. When you change the X-axis variable to modelFiles or Corner, the X-axis labels are displayed as string values.

Labels with string values are not supported for transient data.

To change the sweep variable to modelFiles or Corner, do the following:

  1. Right-click the X-axis and choose Swap Sweep Var.
    The Swap Sweep Var form appears.
  2. Select modelFiles or Corner.
    The graph is plotted with the selected variable displayed on X-axis.
    In the following figure, the sweep variable plotted on X-axis for Supply_Current plot, shown in the figure above, is changed to Corner. Notice that the X-axis labels for corners are displayed as string values and the trace is displayed as a sequence of points.
    To display the trace as a continuous line, right-click the trace and choose Type – Continuous line.

Also, the string for all the intercept points may not be visible on the X-axis when the trace is displayed in its normal size. To view any specific string for a data point, you need to zoom in the graph. For information about how to zoom and pan a graph, see Panning and Zooming Graphs.

If the string is long, it is displayed as an elided string with the ... symbol, for example, CO_VDD...Temp_1. To view the complete string, place the pointer on a data point.

Changing Properties of the String Independent Axis

To change the properties of the independent axis (X-axis) that includes the string intercept values, do the following:

The String Independent Axis Properties for <axis name> form appears.

This form has only the General tab, which includes the following fields:

Adding Multiple Y-Axes

From Results Browser or ADE, if you plot two or more signals that contain different Y-axis (dependent axis) data in the same window, the graph displays separate Y-axes for both the signals. For example, when the voltage (net10) and current (V1:p) signals are plotted in the same graph, the graph displays two Y-axes, displayed on the left and the right of the graph respectively, as shown in figure below:

A graph or a strip can have four Y-axes at the maximum. If the graph already contains four axes and you plot a trace that requires a new Y-axis to be added to the graph, then the new trace is plotted in a new strip.

When you have more than one trace plotted in a graph and you want to analyze a particular trace, you can move the selected trace to a new Y-axis. You can also change the Y-axis of a trace to another existing Y-axis if the graph contains two or more Y-axes. To know more about how to change the axis of a trace, see Changing Dependent Axis (Y-Axis).

To assign a new Y-axis to the selected trace:

When you add a new Y-axis for a trace, the new axis name is displayed in the following format:

axis_number: axis_title(axis_unit)

For example, the above figure displays the following axis name for the new axis that you have added manually to the net10 trace.

3: V(V)

where,

By default, axis name displays the axis_number. To hide axis_number from the axis name, do one of the following:

Changing Dependent Axis (Y-Axis)

If you have more than one Y-axis in a graph, you can change the Y-axis of the trace to another Y-axis. You can assign a common axis to the traces that have the same signal type. However, you cannot assign the same axis to signals of different data types. For example, a voltage signal cannot be assigned an axis of the signal representing current.

To change the Y-axis of a selected trace:

For example, in the following figure, the graph includes five traces:

The net10, net35, and out signals are the voltage signals. Therefore, you can move these signals to any axis that represents the voltage signal. In this example, you can move the out signal to only 3: V(V) axis. The I(mA) axis is disabled in the shortcut menu because it is incompatible with the out signal. The V(V) axis is disabled because the out signal is already assigned to this axis.

When you move both the out and net35 signals to the 3: V(V) axis, the V(V) axis is removed from the graph because no signal is attached to this axis (see the figure below).

To find which traces are assigned to a particular axis, right-click the axis and choose Select Attached Traces. The traces attached to the selected axis are highlighted in the graph. Also, when you select a trace, only the axis for the selected trace is highlighted and all the other axes are dimmed.

To change the properties of all the dependent axis at the same time, do the following:

Plotting Traces Using Different Modifiers

You can plot two signals with different modifiers in the same graph along different Y-axes. In the example below the l1.net26 signal is plotted with Magnitude as dependent modifier and l1.net52 signal is plotted with dB20 as the dependent modifier, the traces are plotted along different Y-axes in the same window.

By default, the Y-axis label displays the name of the modifier, such as Mag (mV). You can change the Y-axis label by using the Axis Properties form.

Now, if you change the dependent modifier for trace l1.net52 to Magnitude, the trace is moved to the existing Y-axis Mag (V).

When you plot these two signals in the same graph with Magnitude as dependent modifier and then change the dependent modifier value of signal l1.net26 to dB20. In this case, both the signals remain plotted on the same Y-axis with label, Mag (V), dB20 (V) (as shown in figure below).

Plotting Multiple Signals on a Common Axis

When you plot signals with different Y-axis values, the signals are plotted on different Y-axes in the same graph. Similarly, when you plot signals with different X-axis values, the signals are plotted in different windows. However, there are some situations where you may need to plot signals with different Y- or X-axis data on a common Y- or X-axis. Following are a few examples where you require plotting signals on the same Y-or X-axis:

To plot multiple signals with different Y- or X-axis values on the same Y- or X-axis, you can do one of the following:

Example

The following figure displays a voltage signal, net10, plotted on a graph. When you right-click the Y-axis, V(V), on this graph and choose Allow Any Units, the Y-axis becomes flexible to plot any signal.

Now, in append mode, if you plot a current signal, V2:p, in the same window, the signal is plotted based on the existing Y-axis values, as shown in the figure below. In this figure, the Y-axis label has changed to Y(*), which shows that you can plot signals of different Y-axis values on this graph.

When you do not select the Allow Any Units option and drag traces on the graph that has different X- or Y-axis units, a context-sensitive message appears in the status bar, which suggests you to either change the axis units or select the Allow Any Units option. Similar context-sensitive messages are displayed when the pointer is moved during other drag-and-drop situations in which dragging of traces is not feasible. These messages vary according to the type of data, intended drop location, and settings of graph and axis onto which the data is dropped.

Merging Two Y-Axes

If you have two or more Y-axes present in a graph to display signals from different Y-axis data, you can merge these two Y-axes and plot the signals along one Y-axis. To do so, perform the following step:

Example

The following figure displays the net26 and net52 signals plotted on two Y-axes, dB20 and phase, respectively.

Now, if you want to change the axis of the net26 signal, right-click the trace for the net26 signal and choose Change Y-axis – Move to phase(deg). The net26 signal is now plotted based on the units on the selected axis. The Y-axis title has been changed to Y(*), which indicates that you can plot any signal on this axis. Also, the Allow Any Units check box for this axis is always selected when the two axes are merged.

Locking Graphs

You can lock a graph to ensure that it does not change even when the simulation results in the data directory are reloaded. No signal can be added or removed from a locked graph. If you try to append a signal to a locked graph, it is plotted in a new subwindow. The graph operations like zooming and adding or moving markers are supported in a locked graph.

To lock a graph:

To lock the size of a strip:

Evaluating Graph Expressions

The signals plotted in the window can have expressions associated with them. How expressions are evaluated in the window depends on whether you are in the SKILL mode.

SKILL Calculator

When you open a saved graph that contains expressions, the expressions are evaluated by default within the context of the current results directory.

For example, if you plot an expression from a results directory and save the graph and later select a different results directory. When you open the saved graph again, the expression in the graph is evaluated in the context of the new results directory.

In the ADE mode, you can set the ignoreTokenContext variable to false so that expressions from the saved graphs are evaluated in the context of the results directory in which the graph was saved.

Working With Assistants

The Virtuoso Visualization and Analysis XL includes the following assistants:

You can hide or show assistants by using the F11 key. Alternatively, click the Toggle Assistants Visibility button on the Workspace toolbar.

Spectrum Assistant

The Spectrum assistant is used to plot and calculate the Fast Fourier Transform (FFT) of a periodic waveform and its different measurements—Signal-to-Noise-and-Distortion Ratio (SINAD), Spurious Free Dynamic Range (SFDR), Effective Number of Bits (ENOB), and Signal-to-Noise Ratio (SNR without distortion) ENOB, SINAD, SNR, SFDR, THD, sigpower, thddb, totalharmpower, peakharmpower, snb, snrh, dcpower—for a given input signal. The spectrum measure is used for characterizing A-to-D converters and is typically supported for transient simulation data.

In Virtuoso Visualization and Analysis XL, Discrete Fourier Transform (DFT) and Fast Fourier Transform (FFT) are the same.

To open the Spectrum assistant, select a signal in the window and do one of the following:

The following figure shows the PSD waveform plotted with Magnitude.

The following figure shows the PSD waveform plotted with dBV/Hz.

The figure below displays a Spectrum plot labeled with input fields, Start and End Frequency, Signal bins, Harmonics, in the Spectrum assistant and explains how these fields are mapped to the output plot.

Outputs

The Outputs section displays the following measurements and their values:

How the Peak Sat. Level value is Calculated?

The Peak Sat. Level or ADC Span is the maximum amplitude the ADC can convert. For example, if the input voltage range of the ADC is [-500mV, 500mV], then the Peak Sat. Level is 500mV.

Calculations

All power values are calculated relative to the Peak Sat. Level. When it is not given or is 0, the peak sat. level is assumed to be 1. No correction factor will be used when calculating ENOB.

Additional Information

Variations on SNR, THD, SINAD and THDN with the Harmonics value of Spectrum assistant:

Total power (T) = Sum of signal, distortion and noise

where,

S = Power in the fundamental signal peak

D = Power in harmonic peaks

N = Noise power between harmonics

Signal to Noise ratio,

Total Harmonic Distortion,

Signal to Noise and Distortion Ratio,

Total Harmonic Distortion Plus Noise,

Number of Harmonics in Spectrum assistant defines how the power is divided between noise (N) and distortion (D).

When Harmonics = 1, all the power except for the fundamental signal peak will be attributed to the noise such that D = 0, THD = 0, and SINAD = SNR.

Increasing the number of harmonics will increase the value of D and reduce N, and thus, greater value of SNR.

For no harmonic peaks in the spectrum, it is assumed that there is no distortion and you can set harmonics equals to 1. Otherwise, always set the harmonics parameter equal to the number of harmonic peaks in the spectrum.

The overlapping between harmonic and DC bins can happen when the width of the signal peak is larger than the frequency resolution.

The Signal bins field controls the width of the signal and harmonic peaks. Frequency resolution is inverse of the time window.

Browser Assistant

The Browser assistant displays the Results Browser that you can use to open simulation results saved earlier. To open the Results Browser, choose Window – Assistants – Browser. For more information about the Results Browser, see Results Browser.

Marker Toolbox Assistant

Use this assistant to add point, vertical, horizontal, and reference point (ARefPoint or BRefPoint) markers to the trace. For more information about Marker Toolbox, see Adding Markers with Marker Toolbox.

Eye Diagram Assistant

You use the Eye Diagram assistant to create an eye. An eye diagram is a way of representing a data signal by repetitively sampling the signal and overlaying the repeated samples on the same X-axis.

The result is a plot that has many overlapping lines enclosing an empty space known as the eye. The quality of the receiver circuit is characterized by the dimension of the eye. An open eye means that the detector can distinguish between 1's and 0's in its input, while a closed eye means that a detector is likely to give errors for certain input bit sequences.

This section includes the following topics:

Overview

Consider an example circuit generated by using a Pseudo-Random Binary Sequence (PRBS) source in the Spectre and Verilog-A model that can add random amplitude variation and random delays to the edges.

Spectre Netlist prbs.scs

// prbs.scs
v1 (high 0) vsource type=prbs period=40n val0=0 val1=1 rise=0.3n \
   fall=0.3n delay=3n
vclk (clk 0) vsource type=pulse period=80n val0=0 val1=1 rise=0.3n \
   fall=0.3n delay=3n
del (withdelay high) randdelay sd=1n rise=0.3n
rl (withdelay jitter) resistor r=100
cl (jitter 0) capacitor c=50p
r1 (high 0) resistor r=1k
ahdl_include "randdelay.va"
tran tran stop=400u

Verilog-A model randdelay.va

// VerilogA for randdelay
`include "constants.h"
`include "discipline.h"
module randdelay (op,ip);
output op;
input ip;
electrical op,ip;
parameter real sd=2.0n;
parameter real gainsd=0.1;
parameter real del=5.0n;
parameter real rise=0.1n;
parameter real thresh=0.5;
parameter integer seed = 23133;
integer vseed;
real randnum,gain,delayed;
analog begin 
@(cross(V(ip)-thresh)) begin
    randnum=$rdist_normal(vseed,0,1);
    randnum=randnum*sd+del;
    gain=$rdist_normal(vseed,0,1)*gainsd+1;
    if(randnum<0) randnum=0.0;
  end
delayed= transition(V(ip),randnum,rise,rise);
V(op) <+ gain*(delayed-thresh)+thresh;
end
endmodule
To run the simulation in the example shown above, type spectre prbs.scs.

When you plot the jitter signal as shown in the previous example, which is the output of the PRBS source that has passed through the Verilog-A model to add random delay and amplitude variation and then passed through a simple RC filter, you get the following plot:

This plot does not show how much the original signal is distorted. The zoomed in waveform also does not help visualize the timing and amplitude variation in the data. These issues can be resolved by using the Eye Diagram assistant.

For more information about the Eye Diagram assistant, see Appendix C, “More About Eye Diagrams.”

Opening the Eye Diagram Assistant

Select a signal in the window and do one of the following to open the Eye Diagram assistant:

You can also drag signals from the Results Browser and directly send them to the Eye Diagram Signal/Expr Names field.
The signals that do not result in generating an eye diagram cannot be added to the Signal/Expr Names field.

When you select the Intensity check box, the graph is displayed as shown below:

This graph helps find the extent of the amplitude variation and timing variation in the transitions. Colors displayed in the graph are used to show regions of greater density, which helps visualize the distribution of amplitude and timing variation.

The opening in the middle of the graph is known as eye. The circuit or the system is considered bad if the opening is small.

Creating Triggered Eye Diagram

The eye diagram is obtained by overlapping several slices of an input transient signal. The width of each slice is called eye period. You can use the triggering options to specify the starting point from where each slice should begin. In a basic eye diagram plot, the slices begin at every eye period interval.

You can select the Triggering check box in the Eye Diagram assistant if you want to setup a trigger period (Internal Triggering) or another signal to trigger the eye diagram instead of a fixed period (Edge Triggering).

You can generate two types of the triggered eye diagram—Internal (Ideal Clock) and External (edge). In the Type field, select the type in the drop-down list.

Internal Triggering

When you select type as Internal(Ideal Clock), the Clock (Trigger) Period field is enabled.

Example

Consider the below example in which transient analysis results are used to generate and analyze the triggered eye diagram of type internal.

  1. Plot Signal from the transient results directory.

Perform the following steps to generate a triggered eye diagram of type internal:

  1. Open the Eye Diagram assistant and plot an eye diagram for this signal with the following field values:
    • Select Signal in the Signal/Expr Names field.
    • Start—0n
    • Stop—200n
    • Eye Period—2.5n
    • Offset—0
  2. Click the Plot Eye button to plot the eye diagram. The following eye diagram appears:
  3. Select the Triggering check box to enable the eye diagram triggering options.
  4. Specify the following field values:
    • Type—Internal(ideal clock)
    • Clock(Trigger) Period—1.25n
    • Plot Mode—New Window
  5. Click the Plot Eye button. The following eye diagram is generated. The new eye generated is placed on the previous eye diagram plot in such a way that the resultant eye diagram is complete and does not skip any period value. Notice that the edges in the Internally triggered eye diagram are symmetrical placed on both the sides.

When you specify the plot mode as append, the internally triggered eye diagram is plotted as shown in the below figure. In this plot, notice that the resultant eye (in yellow) with trigger period = 1.25n is symmetrical on both the sides as compared to the red eye.

External Triggering

When you select type as External(Edge), the Signal, Threshold, Offset, Center Eye, and CrossType fields are enabled.

Example

Consider the below example in which transient analysis results are used to generate and analyze the triggered eye diagram of type external.

  1. Plot signal and trigger (to be used as a trigger signal) from the transient results directory.

Signal:

Trigger:

Perform the following steps to generate a triggered eye diagram of type external:

  1. Open the Eye Diagram assistant and plot an eye diagram for this signal with the following field values:
    • Select Signal in the Signal/Expr Names field.
    • Start—0n
    • Stop—200n
    • Eye Period—2.5n
    • Offset—0
  2. Click the Plot Eye button to plot the eye diagram. The following eye diagram appears:
  3. Select the Triggering check box to enable the eye diagram triggering options.
  4. Specify the following field values:
    • Type—External(edge)
    • Signal—trigger
    • Threshold—0
    • CrossType—rising
    • Plot Mode—Append
  5. Click the Plot Eye button. The following eye diagram is generated.

Shifting Eye Diagram to Center

When the Recommended option is selected in the Eye Settings field, by default the centered eye diagram is created.

When the Custom option is selected, select the Center Eye check box to create the centered eye diagram. The resultant eye diagram has the clock trigger period same as that of the eye period.

Example

Consider the following example in which the simulation results from transient analysis is used to create a eye diagram in the center of the graph. Firstly, plot signal Q_out_p.

Perform the following steps to generate a centered eye diagram:

  1. Open the Eye Diagram assistant and plot an eye diagram for this signal with the following field values:
    • Select Q_out_p in the Signal/Expr Names field.
    • Start—8.3e-07
    • Stop—2.4e-05
    • Eye Period—3.632e-07
    • Offset—0
  2. Click the Plot Eye button to plot the eye diagram. The following eye diagram appears:
  3. Now, select the Center Eye check box. When you select this check box, notice that the Offset field is disabled.
  4. Select Plot Mode as Append.
  5. Click the Plot Eye button. The following eye diagram is generated. The new eye generated (in green) is placed in the center of the graph.

Example: Creating an Eye Diagram

Consider the following setup in ADE Assembler in which you run transient analysis with the given output expressions.

When you run the simulation for this setup, the output expressions are evaluated and the following output is displayed:

Perform the following steps to plot eye diagram:

  1. Plot the v/net1; tran (V) output, as shown in the figure below.
  2. Now, create the eye diagram for this signal by choosing Measurements – Eye Diagram. Select v/net1; tran (V) (Design_Point=1) waveform and specify the following values in the Eye diagram fields:
    • Start=0.0, Stop=10.00n
    • Eye Period=468.9p
    • Select the Center Eye check box to create a centered eye diagram. This helps in carrying out the measurements accurately.
    • Click the Plot Eye button to plot the eye diagram for this signal.

    The following eye diagram is plotted:

Setting Eye Diagram Properties

To change the trace properties of an eye diagram, right-click the eye diagram plot and choose Trace Properties. The Eye Trace Properties for <eye_diagram_name> form appears. It includes the following fields:

Working with the Eye Measurements Tab

After you plot the eye diagram, you can use the Eye Measurements tab to calculate the measurements of the plotted eye and to plot the measurement values.

Click the Eye Measurements tab at the bottom of the Eye Diagram assistant. The fields displayed in the Eye Measurements tab depend on the number of voltage levels you select in the Number of Levels field.

The following figure shows the fields displayed for non-return-to-zero (NRZ), Pulse-Amplitude Modulation 3-Level (PAM3), and Pulse-Amplitude Modulation 4-Level (PAM4).

Example 1: Calculating Measurements and Plotting the BER Curve

Consider the following eye diagram from the setup shown in the Example: Creating an Eye Diagram section. Ensure that the eye diagram is centered so that measurements are calculated accurately.

Perform the following steps to plot the eye diagram, calculate the measurement values, and plot the BER curve for the eye diagram shown in the figure below:

  1. Click the Eye Measurements tab displayed at the bottom of this assistant. The fields displayed in the figure below appear:
  2. Specify the following field values:
    • Select the eye diagram waveform in the graph window.
    • Select NRZ as the modulation scheme.
    • Specify threshold value as 0.
    • Select the Plot BER Curve check box.

    The Outputs section at the bottom displays the measurement values that are calculated when you press the Evaluate button.

The plots for the horizontal histogram, level 0 and level 1vertical histograms, and BER curve appear in the graph window, as shown in the figure below.

The eye width and jitter measurements cannot be calculated and an error message is displayed when more than two peaks are detected in the horizontal histogram for the specified eye. To get the best measurements, it is recommended to select a centered eye diagram with an eye period of 2 UI.

You can also send these advanced measurement values to the ADE window. To do this, right-click a measurement value and choose Send To ADE – Current Expression / Generic Expression.

The expression for the selected measurement appears in the Virtuoso ADE Assembler as shown in the figure below:

If you save the waveform for the BER expression in the VCSV format and the reload the waveform, the VCSV format assigns a Y (myunit) axis to Y-axis, as shown in the figure below. Therefore, the new trace looks different as compared to the original trace plotted from the measurements.

If you want the new trace to look same as that of the original trace, right-click the Y-axis and choose scale as Log Scale, and specify the same range as given in the original plot.

Example 2: Viewing Annotations for Level 0 and Level 1

Consider the following eye diagram plotted for v/net1; tran (V) signal, as shown in the Example: Creating an Eye Diagram section. Ensure that the eye diagram is centered so that measurements are calculated accurately.

Perform the following steps to plot the eye diagram, calculate the measurement values, and view level 0 and level 1 annotations on the eye diagram:

  1. Open the Eye Measurements tab.
  2. Select the eye diagram you plotted and specify the threshold as 0.
  3. Click the Annotate check boxes corresponding to Level 0 and Level 1 sections to view annotations on the eye diagrams (as shown in the figure below).

Computing Advanced Measurements

The Advanced Analysis is computed based on the following two measurement groups— horizontal histograms and vertical histograms. In the figure below, 3 sigma is used for the extent of the data as this represents 99.7% of the values in a normal distribution.

Measurements based on Horizontal Histograms

A horizontal histogram is generated based on the analysis of variation of the times at which the signal crosses the specified threshold level, as shown in the diagram below:

When you click the Evaluate button, the resulting horizontal histogram is plotted. By analyzing the mean and standard deviation of the transition times relative to the beginning of each period, various metrics are computed. The results for the following computations are displayed:

Measurements based on Vertical Histograms

The vertical histogram is created based on the analysis of variation of the signal value in the level 0 and level 1 regions specified in the assistant, as shown in the diagram below:

The level 0 and level 1 regions are those specified by the X and Y ranges in the Eye Diagram assistant. All the Y-points in the waveform within these regions are used to perform the statistical analysis, unless they have been sampled first according to the Sampling Interval field. In the plotted vertical histograms in the above diagram, X-axis represents the amplitude variation.

Advanced Options Results

The calculations for the threshold crossing assume that only a single transition is used; therefore, one additional metric, eye risetime, is computed. In the eye risetime, two thresholds are created at 20% and 80% points between level 0 mean and level 1 mean. At each of these two thresholds, a horizontal histogram is computed (that indicates an analysis of the times of the crossing points of these two thresholds), and the resulting risetime is the difference in the mean crossing time at each of these two thresholds.

Horizontal and Vertical Eye Width

The eye width represents the opening of the eye in the X direction and is computed as:

(Meantransition2 - 3*std(transition2)) - (Meantransition1 + 3*std(transition1))

Consider a waveform that is folded on the X-axis by the length n_period between the start time n_start and stop time n_stop. The following steps are performed to calculate the horizontal eye opening:

The function performs the following steps to calculate the vertical eye width:

Assumptions

The following assumptions have been made while calculating the advanced option values:

Computing the Jitter and BER Values

Consider the following histograms created for the eye_jitter waveform to detect the crossing areas.

The following histograms are created for each side and density estimation is applied to fit each histogram to a distribution J(x), as shown in the figure below:

Working with the Eye Mask Tab

You can evaluate the eye diagram against any violation by using a compliance mask overlaid on the eye diagram waveform. To create an eye mask for the selected eye diagram, you can use the Eye Mask tab available in the Eye Diagram assistant. The eye mask can be of the following geometries: rectangular, hexagonal, diamond, and custom shaped defined in the VCSV file. For example, the figure below shows a hexagonal eye mask.

To know more about how to use eye masks, view the ViVA - Using Eye Masks video available on Cadence Online Support.

In addition, you can read an interesting blog about eye masks, see Virtuoso Video Diary: Eye Masks.

The flow chart below describes how you can create and plot the eye mask for an eye diagram.

This section includes the following topics:

Creating a Centered Eye Diagram

Perform the following steps to select or create the centered eye diagram:

  1. Choose Measurements – Eye Diagram to open the Eye Diagram assistant.
    Two tabs appear at the bottom—Eye Diagram and Eye Mask.
  2. Click the Eye Diagram tab to first create an eye diagram. For more information about how to use the fields, see Eye Diagram Assistant.
The original eye diagram should be centered before adding the eye mask. For details about how to shift the eye diagram to the center, see Shifting Eye Diagram to Center.

Selecting or Creating an Eye Mask

There are three available methods that you can use to create an eye mask. In the first method, you can create a new eye mask based on the given shape standards. To do this, select an eye mask from the given eye mask standards, add the updated mask to the list, and save it in the VCSV file if required.

In the second method, you can select a mask geometry (shape) and then edit the X- and Y-range values and vertex points (corners of the eye mask). Then, add it to the mask list and save it in the VCSV file if required.

In the third method, you can create an eye mask using an existing eye mask, then edit the eye mask shape or coordinates, add the eye mask to the mask list, and save it in the VCSV file if required.

For detailed information about these three methods of creating an eye mask, see the topics below:

Method 1: Creating an Eye Mask Using Existing Eye Mask Standards

You can select a given eye mask standard to create a new eye mask. To do this, perform the following steps:

  1. Click the Eye Mask tab to view the eye mask options. The figure below shows the fields available under the Eye Mask tab.
  2. Now, select an eye diagram in the graph window on which you want to create the eye mask. The selected eye diagram is displayed in the Select Eye field.
  3. In the Mask drop-down list, select an industry standard eye mask template that you want to use.The available options are: HDMI Compliance, HDMI 2.0 TP2EQ (Data Rate 3.4G to 3.712G), HDMI 2.0 TP2EQ (Data Rate 5.94G to 6G), MIPI M-PHY Rx Compliance, MIPI M-PHY Tx Compliance, PCI Express Gen 3 Compliance, and SFP+PCB Compliance.
    By default, this drop-down displays the New Untitled Mask text.
    The selected eye mask is displayed in the mask editing area, as shown in the figure below. The X-axis of this eye mask displays the unit intervals (UI) and the Y-axis displays voltage (V). In addition, the eye mask shape and coordinates vary according to the template you select.
  4. After selecting the eye mask, you can plot and evaluate the eye mask with the eye diagram and send the expression to ADE outputs. For more information, see Plotting and Evaluating an Eye Mask.
  5. Edit the eye mask if required. The Edit Mask section is disabled when you select an industry standard eye mask, which means standard eye masks cannot be edited directly in the drop-down, but you can create a copy of the standard eye mask and edit it. To do this, select a standard eye mask from the Mask drop-down list and click the Add current mask to list button to create a copy of the selected mask. Specify a name for this new mask in the Mask drop-down list and then edit this mask. For more information, see Editing an Eye Mask.
  6. After editing, you can rename the eye mask and add it to the Mask drop-down list. You can also save the eye mask in the VCSV file. For more information, see Performing Various Tasks on an Eye Mask.

Method 2: Creating an Eye Mask Using the Given Shape

Perform the following steps to create an eye mask using the existing shape:

  1. Select Untitled Mask from the Mask drop-down. If you want to create an eye mask using the standard eye mask shape, select the standard mask from the Mask drop-down and add it to the list.
  2. On the Eye Mask tab, enable the Edit Mask check box.
  3. Select a shape from the Mask Geometry drop-down and then change the X Range and Y Range coordinates if required. For more information about how to use the edit mask fields, see Editing an Eye Mask.
  4. Now, click the vertex points in the mask editing area and edit the values. For example, consider you select a hexagon shape as shown in the figure below:
    Now, change the X Range value from 0.25 to 1. The mask position is changed as shown in the figure below. To edit the vertex point, click any of the vertices and type new values in the label. For example, in the figure below, the vertex value is changed from 750m, -150m to 700m, -150m.
  5. Now, save the edited eye mask if required. For information about how to add the eye mask to the Mask drop-down list, and how to save the eye mask, see Performing Various Tasks on an Eye Mask.
  6. After the eye mask is created, you can click the Test Mask button to test the eye mask by plotting it on the specified eye diagram in the graph window.
  7. You can also plot and evaluate the eye mask with the eye diagram and send expression to ADE outputs. To know about how to plot the eye mask, see Plotting and Evaluating an Eye Mask.

Method 3: Creating an Eye Mask Based on the Existing Eye Mask

Perform the following steps to create an eye mask using an already existing eye mask:

  1. Select an already existing eye mask from the Mask drop-down or import an eye mask from the VCSV file. For more information about how to import an eye mask from the VCSV file, see Example of Saving and Importing an Eye Mask in VCSV Format. The selected or imported eye mask is displayed in the mask editing area.
  2. Now, edit the mask shape, range, or coordinates. For information about editing the eye mask, see Editing an Eye Mask.
  3. After the eye mask is created, you can click the Test Mask button to test the eye mask by plotting it on the specified eye diagram in the graph window.
  4. Then, add this edited eye mask with a new name in the Mask drop-down. For example, consider the eye mask named EyeMask_example available in the Mask drop-down. It is of type square. You can select this eye mask and then edit the mask.
    You can then rename this eye mask and add it to the Mask drop-down list. For information about how to add the eye mask to the Mask drop-down list, and how to save the eye mask in the VCSV file, see Performing Various Tasks on an Eye Mask.
  5. After creating the eye mask, you can plot and evaluate the eye mask with the eye diagram and send the expression to ADE outputs. To know about how to plot the eye mask, see Plotting and Evaluating an Eye Mask.

Plotting and Evaluating an Eye Mask

After creating or selecting an eye mask, you can plot and evaluate the eye mask.

To plot the selected eye mask,

To test whether the eye mask passes or fails, click the Test Mask button to plot the eye mask on the specified eye diagram in the graph window.

The Status label at the bottom displays the current status of the eye mask and shows whether the eye mask has passed or failed. By default, the status is Evaluate to test mask.

To annotate and evaluate the eye mask on the selected eye diagram,

Sending an Eye Mask Expression to ADE

To send the eye mask to the ADE Outputs setup pane, choose one of the following options in the Send to ADE drop-down list:

If you send a named mask, the name of the eye mask waveform expression is eye_<signal name>_<mask name>

The name of the named eye mask test expression is eye_<signal name>_<mask name>_test

The unnamed eye masks shows the full expression name.

The figure below shows the eye mask expressions added to the ADE Assembler Outputs setup tab.

Now, when you run the simulation, these expressions are evaluated and the Results tab displays the pass and fail results. The Nominal value indicates the number of periods by which the eye mask is violated.

Editing an Eye Mask

To edit an existing eye mask, select the eye mask from the Mask drop-down list and add it to to the mask list.

To edit the properties of the given mask, select the Edit Mask check box. The options in this group box become available for editing.

When the Edit Mask check box is selected, you can also edit the mask coordinates directly in the mask editing area. Double-click the label and type the new coordinate values.

After the eye mask is edited, you can add the eye mask to the Mask drop-down list. See the next section to know how to perform various operations on the eye mask, such as adding the eye mask to the list, removing an eye mask, saving the eye mask, and importing the eye mask.

Performing Various Tasks on an Eye Mask

After selecting, creating, or editing the eye mask, you can click the following buttons to perform various tasks:

Example of Saving and Importing an Eye Mask in VCSV Format

Consider the example below in which the eye mask named EyeMask_Example is saved in the EyeMask_Example.vcsv file. To save this eye mask, click the Save button. Then, specify the mask filename in the VCSV format, as shown in the figure below.

Ensure that you have the required write permissions on the VCSV file in which you save the eye mask, otherwise an error message is displayed.

After the mask is saved, you can import it later. The coordinates of the eye mask are saved in the VCSV file. For example, the EyeMask_Example.vcsv file has the following contents:

;EyeMask_Example
;X, Y
;Re, Re
;time, V
;s, V
1.758e-10, -0.2
1.5236e-10, 0
1.758e-10, 0.2
2.93e-10, 0.2 
3.1644e-10, 0
2.93e-10, -0.2

You can directly change the coordinates in this file to support arbitrary mask shapes. Now, when you import this file, the changes are reflected in the mask shape. For example, change the file coordinates as shown below to specify a square mask shape:

;EyeMask_Example
;X, Y
;Re, Re
;time, V
;s, V
1.758e-10, -0.0
1.758e-10, 0.2
2.93e-10, 0.2

2.93e-10, -0.2

Now, to import this updated file, click the Import button and select the saved mask filename, EyeMask_Example.vcsv, in the Import Mask form, as shown in the figure below.

The selected eye mask is displayed in the mask editing area as shown in the figure below. Notice that the mask shape has changed now.

The eye mask name, EyeMask_Example, is also listed in the Mask drop-down.

The added or imported eye mask is displayed in the Mask drop-down list only for the current session. You need to import it again for all future sessions.

You can then customize this eye mask by changing the mask shape and coordinates, and save it in a different VCSV file.

You can also use the awvLoadEyeMask SKILL function to load eye masks saved in a VCSV file and add them to the Mask drop-down list of the Eye Mask tab. Each mask is saved into a separate VCSV file.

When you create a custom eye mask, it is available only for the current session. To load the custom eye mask automatically during startup and to display it in the Mask drop-down list, either export the custom mask into a VCSV file or import it from the VCSV file.

Horiz Marker Table Assistant

You use this assistant to view the interception data for horizontal markers in a table. For more information, see Displaying Intercept Data for Markers in Marker Tables.

Trace Info Assistant

You use this assistant to view information about the selected trace. To open the Trace Info, select a trace and choose Window – Assistants – Trace Info. The Trace Info assistant appears, displaying the information, such as trace name and color, Y Min, Y Max, X Min, X Max, Time, Results dir, Dataset, Time, Data Format, and Number of Data points, about the selected signal. It also displays information about the sweep and corner conditions for the selected trace.

To copy the trace properties, right-click the property and choose Copy.

For more information about the data displayed in the trace panel, see Working with Traces.

Vert Marker Table Assistant

You use this assistant to view the interception data for vertical markers in a table. For more information, see Displaying Intercept Data for Markers in Marker Tables.

Transient Measurement Assistant

The Transient Measurement assistant displays the calculated measurements for the transient markers on specific edges. The measurements can be falltime, risetime, overshoot, undershoot, and slewrate values. You can also generate the derived plots for rising and falling edges by using this assistant.

To hide the transient measurement, set the following environment variable in CIW or .cdsinit file:

envSetVal(“viva.rectGraph” “enableEdgeMeasurement” 'string “false”)

This variable is by default set to true.

Before you start using the Transient Measurement assistant, refer to the following topics to understand some basic concepts:

Overview

When you plot a trace and load the waveform, Virtuoso Visualization and Analysis XL analyses the waveform and generates a set of edges, which are referred as threshold (crossing) points. An edge traverses from a low threshold point to a high threshold point (rising edge) or from a high threshold point to a low threshold point (falling edge). Refer to the next section to know more about how to specify the properties of an edge.

Specifying Edge Settings

The Edge Settings form lets you change the edge properties and recalculate the edges.The measurements are displayed in the Transient Measurements assistant.

Do one of the following to open the Edge Settings form:

The Edge Settings form displays a model depicting how the tool calculates edges of the selected trace. The blue reference lines in the model, as highlighted in the figure below, indicate the topline and baseline reference values. You can drag these blue reference lines on the graph to set the topline and baseline values interactively.

This form includes the following fields that you can set to modify settings of the edges for a selected trace:

Calculating Topline and Baseline Values

A threshold point is where the waveform intersects the Y threshold value. A threshold Y value is defined relative to the distance between the baseline and topline values. For example, for the threshold level of 20% and 80%, low and high threshold Y values are calculated as below:

Low threshold Y value == (0.20*(topline-baseline))+baseline

High threshold Y value == (0.80*(topline-baseline))+baseline

The topline (maximum) value is the most frequent value in the upper half of the entire range of trace Y values. Similarly, the baseline (minimum) value will be the most frequent value in the lower half of the entire range of Y values.

By default, the baseline and topline values are calculated automatically using a simple statistical analysis. These values are not original values and only indicate an estimate. Therefore, there might be cases where these values do not result in generating edges. In such cases, you need to specify these values manually. The following environment variables control the topline and baseline reference values:

viva.trace autoReferenceLines string "true"

By default this variable is set to true, which means Virtuoso Visualization and Analysis XL calculates the topline and baseline reference values automatically. If set to false, the values defined by the following environment variable is returned:

viva.trace baseAndToplineReferenceHint string "0.0,3.5"

The edge analysis is performed on transient time waveforms only.

Using Edge Browser

You can use the edge browser to view and analyze the entire set of trace edges, zoom into a smaller range of edges, or zoom into a specific edge. You can use the edge context menu options to analyze a specific edge and annotate the edge with different marker types, such as edge, dx/dy, or period markers. Edge Browser also includes an individual context-menu options that you can use to generate risetime or falltime waveforms derived from the entire set of edges.

Each trace is associated with an individual edge browser, which can be displayed and hidden by clicking the Edge Browser button, as shown in the figure below. The edge browser is hidden in the first strip and displayed in the second strip.

The edges in the graph are calculated only when the Edge Browser is open.

Do one of the following to display the edge browser on the graph:

Note the following:

Context-Sensitive Menus

The two context-sensitive menus are available for edge and edge browser respectively.

Edge Context-Sensitive Menu

The following context-sensitive (shortcut) menu appears when you right-click the edge browser button:

This menu includes the following options:

Edge Browser Context-Sensitive Menu

When you right-click an individual edge in the Edge Browser, the following context-sensitive (shortcut) menu appears:

Using the Transient Measurement Assistant

Perform one of the following steps to open the Transient Measurement assistant:

This assistant includes the following fields:

Using Markers

You can use the following markers to view and examine a specific edge:

Edge Marker

An Edge Marker annotates an edge graphically by using the current edge information. If you update the edges by using the Edge Settings form, the edge markers are also updated to reflect the new edge data. In general, an edge marker shows the top and bottom threshold points of the edge and the risetime or falltime values of the selected edge. When you zoom into the marker, the additional information is displayed to show the baseline and topline values and other details. You can change the threshold value that is displayed by an edge marker. This does not change the edge and only changes the annotation points of the edge marker. If you lock the marker, the intercepts points are not updated when the edges are changed.

For more information about edge markers, see Working With Edge Markers.

The Working with Transient Measurement Assistant video shows how you can use Transient Measurement assistant, create edge markers and change their properties.

Direct Measurements Assistant

You can use the Direct Measurements assistant to quickly perform amplitude, time-domain, and frequency-domain measurements without creating expressions. Using the assistant, you can also annotate these measurements.

This section includes the following topics:

You can watch a video demonstration on how to work with the Direct Measurements assistant at Direct Measurements Assistant. You can also read the related blog at Virtuoso Video Diary: Direct Measurements Assistant in Virtuoso Visualization and Analysis XL.

Opening the Direct Measurements Assistant

To open the Direct Measurements assistant:

Overview of the Direct Measurements Assistant

The Direct Measurements assistant contains the following tabs:

The Amplitude Tab

This section describes how to measure the amplitude of a signal by using the Amplitude tab of the Direct Measurements assistant:

Specifying the Measurement Region

You can specify the measurement region on the X-axis that you want to consider when performing amplitude measurements of a signal.

To specify the measurement region:

  1. Click the arrow next to X Axis Measurement Region to expand the available options.
    The options are displayed, as follows:
  2. Select one of the following options:
    • Visible range: Measurements are performed only on the part of the waveform that is currently visible in the graph window. You can change the visible range by adjusting the pan bar.
    • Entire waveform: Measurements are performed on the entire waveform of the signal.
    • Between markers: Measurements are performed on the part of the signal that is between the vertical markers or point markers.
      In this case, also specify the names of the vertical or point markers in the A and B fields, as follows:
    • Specify: Measurements are performed on the part of the signal that falls between the specified range on the X axis. Specify the range manually in the From and to fields.
  3. Select Show region on axis if you want to display an extent marker over the X axis, highlighting the region of measurement.
    The measurement region is highlighted, as shown in the following figure:

Measuring the Amplitude of a Signal

To measure the amplitude of a signal:

  1. In a graph window, select the signal whose amplitude you want to measure.
  2. From the menu bar of Virtuoso Visualization and Analysis XL, choose Window – Assistants – Direct Measurements.
    The Direct Measurements assistant opens, displaying the selected signal.
  3. In the Maximum section on the Amplitude tab, select one or more of these options:
    • level: To display the location of the maximum value and to highlight the maximum level with dotted lines.
    • peak (vs. min): To display the location of the maximum value and to highlight the peak-to-peak value of the signal.
    • label: To display the maximum value of the signal, name of the signal, and type of the measurement in a label.
  4. In the Minimum section, select one or more of the following fields:
    • level: To display the location of the minimum value and to highlight the minimum level with dotted lines.
    • peak (vs. min): To display the location of the minimum value and to highlight the peak-to-peak value of the signal.
    • label: To display the minimum value and name of the signal, and type of the measurement in a label.
  5. In the Functions section, select one or more of the following fields:
    • Average
      • level: To display the location of the average value and to highlight the average level with dotted lines.
      • label: To display the average value and name of the signal, and the type of the measurement in a label.
    • RMS
      • level: To display the location of the RMS value and to highlight the RMS level with dotted lines.
      • label: To display the RMS value and name of the signal, and type of the measurement in a label.
    • For Peak to peak function, select label to display the peak-to-peak value and name of the signal, and type of the measurement in a label.
  6. In the X Axis Measurement Region section, specify the measurement region on the X axis.
    See the Specifying the Measurement Region section for more information.
  7. Click Create to perform the selected amplitude measurements.

The Time Tab

The following figure shows the various sections of the Time tab.

The following topics describe how to specify various options to perform time-domain measurements using the Time tab:

Specifying Time-Domain Measurements

To specify the time-domain parameter that you want to measure:

  1. From the Measure drop-down list, select one of the following time-domain parameters:
    • Duty cycle
    • Frequency
    • Pulse width
    • Period
    • Rise time
    • Fall time
    • Delay
  2. For Frequency, Pulse width, and Period measurements, select either Positive pulse or Negative pulse.

Specifying Threshold Values

Specifying Edge Threshold Levels

You need to specify the edge threshold levels to measure rise time and fall time.

To specify the edge threshold levels:

  1. From the Measure drop-down list on the Time tab, select either Rise time or Fall time.
  2. In the Edge Threshold Levels section, select one of the following options:
    • 90/10%: The rise time or fall time is calculated, as follows:
      • Rise time: Time taken to reach from A (10% of the peak-to-peak value + initial value) to B (90% of the peak-to-peak value + initial value).
      • Fall time: Time taken to reach from A (90% of the peak-to-peak value + initial value) to B (10% of the peak-to-peak value + initial value).
    • 80/20%: The rise time or fall time is calculated, as follows:
      • Rise time: Time taken to reach from A (20% of the peak-to-peak value + initial value) to B (80% of the peak-to-peak value + initial value).
      • Fall time: Time taken to reach from A (80% of the peak-to-peak value + initial value) to B (20% of the peak-to-peak value + initial value).
    • Specify absolute: Specify the absolute threshold values in the High and Low fields.
      The rise time is calculated as the time taken by the signal to reach from the specified low value to the specified high value.
      The fall time is calculated as the time taken to reach from the specified high value to the specified low value.

Specifying the Method to Calculate High and Low Levels

In the High/Low Levels section of the Time tab, specify how you want to calculate the high and low levels of the signal:

Important points:

Specifying Annotate Options

In the Annotate section of the Time tab, specify how you want to annotate the measured values:

Measuring Delay between Signals

To measure the delay between two signals:

  1. Plot the signals in a graph window.
  2. From the menu bar of Virtuoso Visualization and Analysis XL, choose Window – Assistants – Direct Measurements.
    The Direct Measurements assistant opens, displaying the selected signals.
  3. From the Trace A and Trace B drop-down lists, select the edge type of the signals.
  4. In the Trace A Settings and Trace B Settings sections, specify the threshold, high, and low-level values of trace A and trace B, respectively.
    Refer to the Specifying Threshold Values and Specifying the Method to Calculate High and Low Levels sections for more information.
  5. In the Annotate section, select one of the following options:
    • Only first cycle: Annotates the measurement only for the first cycle of the signal.
    • Maximum value: Annotates the maximum value of the measurement.
    • Minimum value: To annotate the minimum value of the measurement.
    • All values as waveform: All measurement values are plotted against the time, thereby constituting a waveform.
  6. Click Create.
    The delay between signals is measured and annotated in the graph window.
    The following example shows the delay measured for the 50% levels of the signals between the first rising edge of trace A and the first falling edge of trace B.

The Freq Tab

This section describes how to use the Freq tab of the Direct Measurements assistant to measure frequency-domain parameters:

Measuring the Bandwidth of an AC Signal

To measure the bandwidth of an ac signal:

  1. In a graph window, select an ac signal whose bandwidth you want to measure.
  2. From the menu bar, choose Window – Assistants – Direct Measurements.
    The Direct Measurements assistant opens, displaying the selected signal.
  3. On the Freq tab, from the Measure drop-down list, select Bandwidth.
  4. From the Threshold drop-down, select either 3dB or 6dB.
  5. From the Band options, select one of the following response types: Low pass, High pass, and Band pass.
    For more information about these options, refer to the bandwidth Calculator function.
  6. Click Create.

Measuring Stability Margins

To measure stability margins of an ac signal:

  1. In a graph window, select an ac signal whose stability margins you want to measure.
  2. From the menu bar of Virtuoso Visualization and Analysis XL, choose Window – Assistants – Direct Measurements.
    The Direct Measurements assistant opens, displaying the selected signal.
  3. In the Freq tab, from the Measure drop-down list, select Stability margins.
  4. In the Stability section, select the stability measures by clicking the following check boxes:
    • Gain margin: To measure the gain margin. Refer to gainMargin for the definition.
    • Phase margin: To measure phase margin. Refer to phaseMargin for the definition.
  5. In the Annotate section, select one of the following options:
    • In place: The gain and phase margin measurements are annotated in the same subwindow where the trace is present.
    • In new subwindow: The gain and phase margin measurements are annotated in a new subwindow. Select one of the following options:
      • As Bode plot (gain/phase vs. frequency): The gain in dBs and phase in degrees are plotted against the frequency in Hertz.
      • As Nichols chart (gain vs. phase): The gain in dBs is plotted against phase in degrees. Using this chart, measures of stability (phase margin and gain margin) can be read directly.
  6. In the Marker Options section, select one of the following:
    • Use reference level markers: The stability margins in the Bode plot are annotated using reference level markers, as shown in the following figure:
    • Use horizontal markers: The stability margins in the Bode plot are annotated using horizontal markers, as shown in the following figure:

The Compare Tab

The following figure shows the various sections on the Compare tab of the Direct Measurements assistant.

Using the Compare tab, you can compare two waveforms, say ‘A’ and ‘B’. The first waveform ‘A’ is referred to as the reference waveform and the second waveform ‘B’ is referred to as the compared waveform.

For each data point of the reference waveform ‘A’, an acceptance or tolerance region is marked based on the absolute and relative tolerances and the offset values. If the corresponding data point on the compared waveform ‘B’ falls within the acceptance region, it is marked as pass. The data point on the compared waveform ‘B’ that falls outside the acceptance region is marked as fail. This process is repeated for all data points.

Comparison Algorithms

The Direct Measurements assistant uses the following algorithms for waveform comparison:

For more information about these comparison algorithms, refer to the Waveform Compare Algorithms section the Virtuoso ADE Assembler User Guide.

Acceptance or Tolerance Region

Acceptance or tolerance region is calculated based on the following values:

Consider the following waveforms, ‘A’ and ‘B’, where ‘A’ is the reference waveform and ‘B’ is the waveform to be compared.

The following examples describe how tolerance or acceptance region is calculated based on the different values of Absolute tolerance, Relative tolerance, and Offset.

Example 1

This example describes the calculation of the acceptance region based on the following values:

 Y value X value
Absolute tolerance

0.15V

0ns
Relative tolerance

10%

N/A
Offset

0V

0ns

Consider the data point 1 at 1V on the reference waveform ‘A’.

y-deviation range based on Absolute tolerance: 1±0.15V = 0.85V–1.15V

y-deviation range based on Relative tolerance: 1±(10% of 1V) = 1±0.1 = 0.9V–1.1V

The maximum deviation range of the two is considered as the acceptance or tolerance region: 0.85V–1.15V

There is no shift in the acceptance region because the Offset value is not specified

Observe that the points that fall within the acceptance region are marked as pass, while those fall outside the acceptance region are marked as fail.

Example 2

This example describes the calculation of the acceptance region based on the following values:

 Y value X value
Absolute tolerance

0.15V

0ns
Relative tolerance

10%

N/A
Offset

0.1V

0ns

Consider the data point 1 at 1V on the reference waveform ‘A’.

y-deviation range based on Absolute tolerance: 1±0.15V = 0.85V–1.15V

y-deviation range based on Relative tolerance: 1±(10% of 1V) = 1±0.1 = 0.9V–1.1V

The maximum deviation range of the two is 0.85V—1.15V

The acceptance or tolerance after considering the Offset value of 0.1V: (0.85+0.1)V–(1.15+0.1)V = 0.95V—1.25V

All the data points fall within the acceptance region, therefore no points of failure are reported.

Example 3

This example describes the calculation of the acceptance region based on the following values:

 Y value X value
Absolute tolerance

0.15V

0.2ns
Relative tolerance

0%

N/A
Offset

0.1V

0ns

Consider the data point ‘1’ at 1V on the reference waveform ‘A’.

y-deviation range based on Absolute tolerance: 1±0.15V = 0.85V–1.15V

y-deviation range based on Relative tolerance: 1±(10% of 1V) = 1±0.1 = 0.9V–1.1V

The maximum deviation range of the two is: 0.85V—1.15V

The acceptance or tolerance after considering the Offset value of 0.1V: (0.85+0.1)V–(1.15+0.1)V = 0.95V—1.25V

x-deviation range based on the Absolute tolerance (time tolerance): 9.2±0.2ns = 9ns–9.4ns

Observe that if you specify absolute tolerance values for both x and y axes, the acceptance region is marked as rectangular boxes. Unlike the vertical lines that appear when you specify tolerance values only for the y axis.

All the data points fall within the acceptance region, therefore no points of failure are reported.

Comparing Waveforms

To compare waveforms:

  1. From the menu bar of Virtuoso Visualization and Analysis XL, choose Window – Assistants – Direct Measurements.
    The Direct Measurements assistant opens.
  2. Click the Compare tab.
  3. Click the A field, and then select the first waveform in the graph window or the subwindow. This waveform is considered as the reference waveform.
  4. Click the B field, and then select the second waveform in the graph window or the subwindow. This waveform is considered as the compared waveform.
  5. From the Algorithm drop-down list, select a comparison algorithm.
    See the Comparison Algorithms section for more information.
  6. In the Y value group, specify the Absolute tolerance, Relative tolerance, and Offset values for y axis.
    See the Acceptance or Tolerance Region section for more information.
  7. In the X value group, specify the Absolute tolerance, Offset, and Glitch filter values for x axis.
  8. In the Glitch filter field, specify the maximum glitch size (in seconds) up to which the glitches in digital signals are acceptable and ignored while comparing waveforms.
    This field appears dim and becomes available only when you compare digital signals.
  9. Select the Preview tolerances on Trace A check box if you want to preview the tolerance or acceptance regions.
  10. In the X Axis Measurement Region section, specify the measurement region on the x axis.
    See the Specifying the Measurement Region section for more information.
  11. Select the Show region on axis check box to display an extent marker over the x axis, highlighting the region of measurement.
  12. Click Create to compare the selected waveforms.

Editing Properties of Direct Measurements

To edit properties of a direct measurement:

  1. Right-click a direct measurement marker, label, or bookmark and then choose Direct Measurement Properties.
    The Direct Measures Marker Properties for <measurement name> form appears.
  2. Edit the following properties on the form, as required:
    1. Font/Color — Specifies the font and color of the direct measurement marker, label, or bookmark.
    2. Notation — Specifies the notation of the direct measurement. Possible values are Scientific, Engineering, and Suffix. The default value is Suffix.
    3. LineStyle — Specifies the line style of the direct measurement marker, label, or bookmark. Possible values are Solid, Dot, Dash, DashDot, and DashDotDot. The default value is Solid.
    4. Significant Digits — Specifies the number of significant digits to be displayed in the measured values. The default value is 4. To change this value, you need to first select Manual from the drop-down list.
  3. Click OK to save the changes and close the form.

Deleting Direct Measurements

To delete the annotations of direct measurements, right-click a direct measurement marker, label, or bookmark, and then choose Delete Direct Measurements.

Customize Trace Groups Assistant

This assistant is used to customize the trace settings for the traces that belong to a common family.

Perform the following step to open the Customize Trace Group assistant:

The traces in the graphs are updated based on the filter value you select in each field. The filter values can be: none, trace, leaf, family, Corner, and sweep variables.

You can also view a related blog post to know more about how to organize waveform families.

Example1: Displaying traces belonging to a common family in one strip:

Set the fields in the Customize Trace Settings assistant as shown in the figure below:

When you click the Apply button, the traces in the graph are updated as shown in the figure below. Notice that traces belonging to a common family (V0:p and OUT) are displayed in the same strip.

Example2: Displaying traces that belong to a common VDD value in one strip and common corners in same color:

Set the fields in the Customize Trace Settings assistant as shown in the figure below:

In this example, notice that the traces with similar VDD value are displayed in the same strip and traces that belong to similar corners are displayed in same color.

Example3: Displaying traces that belong to a common temperature value with same type of symbols displayed on them

Set the fields in the Customize Trace Settings assistant as shown in the figure below:

In this example, notice that the traces with similar temperature value are displayed in the same color and also display the similar types of symbols on them.

Displaying Traces having Same Values for a Sweep Variable in the Same Linestyle

To display traces that have same values for a sweep variable using the same line style:

  1. From the menu bar of Virtuoso Visualization and Analysis XL, choose Window—Assistants—Customize Trace Groups.
    The Customize Trace Groups assistant opens.
  2. In the Customize Trace Groups assistant, set the fields as follows:
    • Strip: Family
    • Color: None
    • Symbol: None
    • Linestyle: temp
  3. Click Apply.

The traces that have the same value for the sweep variable temp are displayed in the same line style.

In the following example, all the traces of family net30 and net10 that have same value 50 for the sweep variable temp, are displayed using the same line style, dot.

Working with Workspaces

A workspace is the arrangement of various assistants and the window settings that you specify while working with a graph. You can either use the available workspaces or create your own workspace while working in the window.

Workspace Types

The available workspaces are of four types:

If you open the tool in stand-alone mode, it is opened in the Basic workspace because in stand-alone mode you work on the saved simulation results.

If you open the tool from within ADE, it is opened in the Classic workspace because in ADE you work on the simulation results for the current run.

When you open a new Virtuoso Visualization and Analysis XL session from the same Virtuoso window, the workspace that you specified in the previous session is available.

Saving a Workspace

You can customize a workspace by selecting the assistants that you want to display from the Window – Assistants menu. You can then save the customized workspace by doing one of the following:

If you do not want to save tWorking With Assistantshe changes you made to the existing workspace, choose Windows – Workspaces – Revert to Saved to revert to the factory settings.

Loading a Workspace

To load a workspace, do one of the following:

Deleting a Workspace

To delete a workspace, choose Windows – Workspaces – Delete.

The Delete Workspace form appears. Select the name of the workspace that you want to delete.

Setting the Default Workspace

To set a workspace as the default workspace, choose Windows – Workspaces – Set Default.

The Default Workspace form appears. Select the name of the workspace that you want to set as the default.

Showing and Hiding Assistants

To show or hide the assistants in the workspace, do one of the following:

Working with Traces

A signal when plotted in the window is called a trace. Each trace in the window is displayed in a different color. The graph supports 18 unique colors. Information, such as, Name, Vis (visibility of the trace), Spec, Region, History, Test, and Design Point, can be displayed as columns in the area to the left of the trace is called the trace legend. A splitter line separates the trace and the trace legend area. You can double-click the splitter line to adjust the width of the trace legend area.

To highlight a trace in the window, select the legend corresponding to the trace or select the trace in the graph.

The trace legend area displays information in the following columns:

The corner names and sweep parameters from ADE in separate columns that can be sorted.

The trace families, based on sweep parameters, in a hierarchical order. To view the analog traces in a family or the digital traces in a bus, click the + symbol in the trace legend area.

Filtering Trace Legends

You can use the Legend Filter form to:

Opening the Legend Filter Form

The location of the legend filter icon, , depends on the legend position specified on the Graph Options tab of the Graph Properties form. The following table shows the location of legend filter icon for different legend positions.

Legend Position Location of the Legend Filter Icon

Left

Inside

Above

Applying Filters to Traces

You can apply filters to the traces in the Legend Filter form to selectively view the traces that you want to work upon.

Perform the following steps to apply filters to the traces:

  1. Right-click anywhere in a filter field to specify the advanced filter options, as shown in the following figure.
    The following table describes the various advanced filter options.
    Advanced Filter Options Description

    Find With

    Using this option, you can set the filter criteria to search:

    • All of the words specified in the filter field
    • Any of the words specified in the filter field
    • The exact phrase specified in the filter field
    • Results that do not contain the words specified in the filter field

    Match Word

    Using this option, you can set the filter criteria to match:

    • Substring: displays the column with the values containing the filter criteria
    • Prefix: displays the columns with values starting with the filter criteria
    • Exactly: displays the columns with values matching exactly with the filter criteria
    • Suffix: displays the columns with values ending with the filter criteria

    Using Case

    Using this option, you can set the filter criteria to:

    • Insensitive Match: filters the results regardless of the case specified in the filter field
    • Sensitive Match: filters the results matching the case specified in the filter field
  2. Enter the filter criteria in the filter field below the required column header.
    The following examples show how you can set the filter criteria:
    • Filter values that are greater than the specified value
      If you want to view only the traces for which temperature value is greater than 75, type >75 in the filter field below the temp column, as shown in the following figure.
    • Filter values that are less than the specified value:
      If you want to view only the traces for which vdd value is less than 4.9, type <4.9 in the filter field below the vdd column, as shown in the following figure.
    • Filter values that are in the specified range:
      If you want to view only the traces for which vdd value is greater than 4.5 and less than 5.3, type >4.5 <5.3 in the filter field below the vdd column, as shown in the following figure.
  3. You can apply multiple filters in the Legend Filter form. The following figure shows an example where more than one filters are applied to the traces.
  4. Select the Set Visibility by Filter check box if you want to view only those traces in the graph that meet the filtering criteria. The following figure shows an example of how the visibility of the traces in the graph is automatically set based on the applied filters when you select the Set Visibility by Filter check box.

Important Points to Note

Viewing Information about the Traces

Some Useful Features

Displaying History, Test, and Design Point Information in Graphs

When you plot waveform results for a particular history in Virtuoso Visualization and Analysis XL, the related history, test, and design point information for the plotted waveform is displayed at the following locations:

Trace Legend

The trace legend of the graph includes columns to show the History, Test, and Design Point information. By default, these columns are not displayed in the trace legend. To display them, right-click anywhere in the column header and choose the required column, as shown in the figure below.

Trace Info Assistant

The Trace Info assistant displays the History and Test information about the trace that is currently selected in the graph window, as shown in the figure below:

Status Bar

When you move the mouse pointer over a trace in the graph window, the status bar displays its history, test, and design point information, as shown in the figure below:

Markers

You can add the following marker labels to show information about history, test, and design point using the Create Graph Marker form.

The following figure shows the marker labels added on the point marker M1.

You can also read the Virtuosity: Identifying Those Traces blog for more information about these marker labels.

Selecting Traces

You can select one or more traces in a graph by doing the following:

The active strip is determined by a yellow bar displayed to the left of the trace legend area.
When you select multiple traces in the trace legend or select all the traces by using the Trace - Select All - In Graph menu command, then only the topmost group in the trace legend is expanded and the other groups are displayed in the non-expanded form. Also note, after the selection is made, all the traces remain selected irrespective of the expanded and non-expanded groups.

Using Trace Menu Commands

You can select a trace and choose one of the following Trace menu commands to manipulate traces in a window:

To show or hide traces, right-click the trace and choose Visible. The red check mark is displayed with this option indicating that the trace is visible.

When you move a trace to a new window, the moved trace is plotted with the same x-axis scale in the new window.

Setting the Style of the Traces

To set the style of a trace, right-click anywhere on a trace to open the trace menu commands, and then choose Style – options.

The following table describes the different styles that you can apply to a trace.

Style Options Example

Solid

Dot

Dash

DashDot

DashDotDot

You can also change the styles of the trace by setting the following environment variable:

envSetVal("viva.trace" "lineStyle" 'string "solid")

Valid values are: solid, dot, dash, dashdot, dashdotdot

Setting the Thickness of the Traces

To set the width of a trace, right-click anywhere on a trace to open the trace menu commands, and then choose Width – options.

The following table describes the different width that you can apply to a trace.

Width Options Example

Thin

Medium

Thick

ExtraThick

You can also change the thickness of the trace by setting the following environment variable:

envSetVal("viva.trace" "lineThickness" 'string "fine")

Valid values are: fine, medium, thick, extrathick

Setting the Color of the Traces

To set the color of a trace, right-click anywhere on a trace to open the trace menu commands, and then choose Color – options.

You can also change the color of the trace by setting the following environment variable:

envSetVal("viva.trace" "hiliteColor" 'string "lime")

Dragging Traces

Traces support the following drag-and-drop operations:

Tracking Cursor

The tracking cursor displays the color and name of the trace and its X- and Y-axis values when you drag a trace. Do one of the following to display tracking information on the tracking cursor:

Hiding and Showing Traces

To show or hide a trace, do the following:

Deleting Traces

To delete a trace from a graph, subwindow, or strip, do one of the following:

To delete all traces in a subwindow, select a trace and do one the following:

Setting Trace Properties

The default trace properties are controlled by the values assigned to variables in the .cdsenv file. For more information, see Appendix A, “Virtuoso Visualization and Analysis XL Tool Environment Variables.”

Follow these steps to set the trace properties for a trace:

  1. Select a trace and choose Trace – Properties.
    Alternatively, double-click a trace in the window.
    The Trace Properties for <trace-name> form appears.
  2. In this form, set the trace properties:
    1. In the Name field, type the name for the trace or select the Default check box to display the default trace name. When you select the Default check box, the Name field becomes unavailable. The Name and Default fields are not available if you select more than one trace.
    2. In the Expression field, type the expression associated with the selected trace or get the expression from the Calculator Buffer.
    3. In the Type/Style fields, do the following:
      • Specify whether you want to represent the trace by a line, points, histogram, bar, spectral, or sampleHold.
      • Specify whether you want the trace style to be Solid, Dashed, Dotted, or DotDashed, or DashDotDot.
        The trace style option does not work for Bars and Spectrum.
      • Specify whether you want the trace to be Fine, Medium, Thick or ExtraThick.
        The trace thickness option does not work for Bars and Spectrum.
    4. In the Symbols field, select the Show All Points check box to display data points on the trace and specify the number of points to be displayed.
    5. In the Points per Symbol field, specify whether you want data points to be displayed on the trace as symbols of Point, Dot, Plus, Square, Box, X, Circle, and so on.
    6. In the Color field, select the foreground color for the trace. Alternatively, you can also set the trace color by right-clicking the trace and selecting Color.
    7. Click OK.
      You can also select these properties by right-clicking a trace.

For more information about the selected trace, choose Window – Assistants – Trace Info Panel. The Trace Info Panel assistant appears, displaying the Name, Max value, Min value, and Data points of the selected trace.

Setting Digital Trace Properties

To change the properties of a digital signal, right-click the digital signal and choose Digital Trace Properties.

The Digital Trace Properties for <signal name> form appears. This form includes the following fields:

  1. Name—Specify the name for the trace or select the Default check box to display the default trace name. When you select the Default check box, the Name field becomes unavailable. The Name and Default fields are not available if you select more than one trace.
  2. Style—Specify whether you want the trace style to be Solid, Dashed, Dotted, or DotDashed, or DashDotDot. And, specify whether you want the trace width to be Fine, Medium, Thick or ExtraThick. Alternatively, you can set the trace style and width by right-clicking the trace and selecting Style and Width respectively.
  3. Color—Select the foreground color for the trace. Alternatively, you can set the trace color by right-clicking the trace and selecting Color. By default, the trace is displayed in green.
  4. Click OK.

Setting Properties for Multiple Traces

You can set the properties for more than one trace at a time. To perform this, select the traces by using the Ctrl key and choose Trace – Properties.

The Trace Properties for selected objects form appears.

You can change the form fields by clicking the arrow button adjacent to each field name (as highlighted in the figure above).

You can also use this method to change the properties of markers of similar marker type. For example, select markers of similar marker type by using the Ctrl key, such as two or more vertical markers, and choose Marker – Properties. The <Marker-name> Properties for selected objects form appears. You can then use this form to change the properties for selected markers in a single step.

Displaying Symbols on a Trace

To display symbols for the data points on a trace, do one of the following:

You can control the symbol type and the number of data points that can be identified by the symbols. The symbol used for the trace is displayed next to the trace name.

The following figure illustrates how two traces can be distinguished by using symbols for the data points.

Exporting a Trace

To export a trace from the window in a variety of formats and later load it in the required application. You can also save a clipped part of the dataset by specifying the start and end values, or interpolate the data before saving it. By exporting a trace, you can also save the expressions associated with the trace.

To export the trace, do one of the following:

Sending Trace Expressions to Calculator

To send the expression associated with a trace in the window to the Calculator, select the trace for which you want to send the expression to the Calculator and do one of the following:

Sending Traces to ADE

To include the expressions for the traces displayed in a graph directly to ADE Outputs Setup tab, right-click a trace and choose Send To – ADE. The expression for the selected trace is added to ADE as a new output and evaluated when you run the simulation.

You use this option if you want to evaluate the expression for the trace in the current simulation run in ADE.

When you send the measurement values obtained from assistants to ADE, such as Eye Diagram and Spectrum toolbox, the alias name in the ADE displays the assistant name and the measurement name. For example, if you send the DC Power value from Spectrum toolbox to ADE, it is displayed with the spectrum_dcpower alias name. Similarly, the Level0 Mean value calculated from Eye Diagram is displayed with the eye_level0Mean alias name.

When you plot a signal from Results Browser, then right-click the plotted signal in the graph window and choose Send To – ADE, the expression for the plotted signal is added in the ADE Explorer or ADE Assembler Outputs Setup pane, as shown in the figure below:

If you are using the Refresh feature in ADE Explorer or Assembler, the traces that you include into ADE Explorer or Assembler from the graph are also updated with the new simulation data.

Working with Strips

You can append multiple traces to a graph. If you want to view the individual traces, you can split the graph into strips that are arranged vertically. Each strip has its own Y-axis and shares the X-axis with the other strips. The window displays the trace legend separately for each individual strip.

The active strip is determined by a yellow bar displayed on the left of the strip. If you want to change the order in which the strips are displayed, drag the strips. You can drag a strip to any of the following locations:

You can also resize the active analog strip by dragging the strip splitter.

This section includes the following topics:

Splitting Strips

In the following figure, the signals net10 and out are displayed in a single strip. Both the signals constitute a family of waveforms, containing 30 child traces grouped together. Each of these child traces represents a waveform of the signal plotted for different set of temp and vdd values.

temp and vdd are the sweep variables used in this example.

You can split the strip in any of the following ways:

Combining Graph Strips

You can combine one or more strips by dragging them to a single strip.

Consider the following graph window, where various analog and digital traces are plotted in different strips.

To combine digital signals into one strip and to combine analog signals into another strip, do one of the following:

Moving Traces

Do one of the following to move the selected traces in a graph to a new window, subwindow, or strip:

Copying Traces

Do one of the following to copy the selected traces in a graph to a new window, subwindow, or strip:

Setting Strip Properties

You can set the heights of strips by using the Strips tab on the Graph Properties form.

To set the heights of the strips:

  1. Do one of the following to open the Graph Properties form:
    • Choose Graph – Properties.
    • Right-click anywhere in the graph window and choose Graph Properties.

    The Graph Properties form appears.
  2. On the Strips tab, set the Minimum values of Analog Height and Digital Height of the strips of analog and digital signals, respectively.
  3. Click Plot into New Strips check box if you want to plot analog traces into new strips.
  4. Click Apply, and then click OK.
    Consider the following graph window in which analog signals (net38 and net018) and digital signals (dig1 and dig2) are plotted in strips with their default heights.
    The following figure shows how the strip heights of the analog and digital signals change when you set the Minimum value of Analog Height to 20 and Minimum value of Digital Height to 200.
    The following figure shows how the strip heights of the analog and digital signals change when you set the Minimum value of Analog Height to 200 and Minimum value of Digital Height to 20.

Locking and Unlocking Strips

You can lock and unlock a strip while splitting the traces into different strips.

To lock a strip, right-click anywhere in the window and choose Lock Strip Size. A red check mark is displayed before this command and a lock icon appears at the top right corner of the strip, displaying the strip in the locked mode. If you change the size of any other strip in the window, it does not change the size of the locked strip.

To unlock the strip, right-click anywhere in the window and choose Lock Strip Size. The lock icon is no longer displayed and you can resize the strip now.

The Using Strip Charts in Qt Graph video demonstrates how to split and combine analog traces into strips, resize strips, plot the trace to a new strip, and split and combine traces from sweep data.

Working with Sweeps

To display the sweep data for a family in the same strip, choose Trace – Strip by Family before plotting the sweep data. Now, if you select to display traces in strips, each trace family is displayed in a separate strip.The trace legend area displays the traces in the family. Click the + sign to view all traces.

To display the traces from the sweep data in individual strips, ensure that the Trace – Strip By Family is not selected. Then, right-click anywhere in the graph and choose Split Current Strip.

Changing Trace Properties for Family

To change the properties of a trace in the family, right-click the trace in the trace legend and choose Trace Properties. For more information about how to use the Trace Properties form, see Setting Trace Properties.

To change the properties of all traces in the family, select the traces by using the Ctrl key and choose Trace Properties. The Trace Properties for selected objects form appears. For more information about this form, see Setting Properties for Multiple Traces.

To change the trace group properties for a family of traces, right-click the family header in the trace legend and choose Trace Group Properties. The TraceGroup properties for family-name form appears.

Swapping Sweep Variables

The sweep data can include multiple sweep variables; however, you can plot sweep data analysis results by using only two variables at a time. If you want to plot the sweep data results with another variable, you can swap the X-axis variable with this variable.

To swap the sweep variables in the graph:

Plotting Graph across Fixed Frequency

The graph shown in the figure below is obtained from an AC analysis run on sweep data. In this graph, the signal V0:p is plotted against frequency on X-axis.

If you want to plot this graph against another sweep variable, temperature, and analyze the plot at a particular frequency, specify the frequency value in the X Value field in the Swap Sweep Var form (as shown in the figure below).

The graph is now plotted against temperature for frequency=1000 Hz (as shown in the figure below).

Plotting Graph across Fixed Time

The graph shown in the figure below is obtained from a transient analysis run on sweep data. In this graph, the signal V0/PLUS and OUT are plotted against time on X-axis.

If you want to plot this graph against another sweep variable, VIN_CM, and analyze the plot at a particular time value, specify a time value in the X Value field in the Swap Sweep Var form (as shown in the figure below).

The graph is now plotted against VIN_CM for time=50s (as shown in the figure below).

Filtering Traces Using Sweep Visibility Filter

To display in a graph specific traces that belong to a selected sweep data range, you can filter the traces by using the sweep visibility filter option. Filtering helps you analyze the simulation data in a specific sweep range.

The figure below shows the OUT and V0:P traces that are plotted after running a simulation is run in ADE XL for sweep data. The X-axis sweep variables for this simulation are—modelFiles, VDD, temperature, freq, and Corner. The graph below is plotted with freq as the sweep variable on X-axis.

You can select different combinations of sweep variables to filter the visibility of traces that you want to display in the graph. For example, in the graph shown above, you can select a specific range of other sweep variables—modelfiles, VDD, and temperature—to filter traces. The traces that fall in the range you have selected are visible in the graph and the visibility of remaining traces is turned off.

To filter traces from sweep data, perform the following steps:

  1. Choose Graph – Filter By Sweep Var.
    The Sweep Visibility Filter form appears. The form name includes the subwindow name, as shown below.
  2. Select the variable values for which you want to display traces in the graph. For example, the form displayed in the figure above shows the following four traces selected for the modelFiles:VDD:temperature combination:
    gpdk045.scs:tt, 1.6, -25
    gpdk045.scs:ss,1.8, -25
    gpdk045.scs:ff, 1.8, -25
    gpdk045.scs.tt, 2, -25
  3. Click Apply.
    The traces for the selected combination of modelFiles, VDD and temperature values are displayed in the graph.
The visibility icon in the trace legend area is ON only for the selected combination of sweep variables, as shown in the figure above.

You can also filter traces by selecting the Set Sweep Ranges option in the Results Browser. For more information, see Plotting a Transient Signal Over a Time Range and Plotting an AC Signal over a Frequency Range.

Working with Graph Labels

You can add labels in a graph to display information about the graph or a trace. You can also attach labels with markers. For information about how to attach and edit the labels on marker, see Adding Markers.

To add a graph label in a graph, do one of the following:

A label is added to the graph you selected. By default, the label displays the string Graph Label1. You can change the graph label by double-clicking the displayed string.

To add a new line in the graph label, press Enter. The new line and carriage return characters are also supported in the graph labels.

To change the graph label properties, do one of the following:

You can change the position of a graph label by dragging the graph label to a new location.

Deleting Graph Labels

To delete a graph label, do one of the following:

Creating Multiple Graph labels

To create multiple graph labels, right-click a label in the graph and choose Copy. Then, right-click any where in the window and choose Paste. A copy of the graph label is created. Drag one of the labels to the required new position. Using this method, you can create as many labels as you want.

You cannot move a label that is attached to a marker.

Plotting WREAL Signals

Virtuoso Visualization and Analysis XL supports the plotting of WREAL (wire-real) signals, where the WREAL signals are by default plotted in the sample and hold plot type. The WREAL signals are displayed with the symbol in the Results Browser.

If you want to disable the WREAL plotting, set the vivaWrealSupport environment variable to false:

setenv vivaWrealSupport false

Perform the following step to set the plot type of a trace to sample and hold:

By default the data points are visible in the plots for the WREAL signals. To hide the data points, do one of the following:

To change the plot type to a continuous line, right-click the trace and choose Type – Continuous line.

To change the properties of a WREAL trace, right-click the trace and choose Trace Properties. The Trace Properties for <WREAL trace name> form appears. This form includes the similar fields as that of the rectangular trace. For more infomation about the fom fields, see Setting Trace Properties.

WREAL plots includes a special depiction style to display the X and Z states. In the figure below, the red blocks indicate the X state and the yellow blocks indicate the Z state.

Limitations

Following are the limitations while plotting the WREAL signals:

Plotting YvsY Graph

To plot a YvsY graph for the sweep data, do the following:

YvsY of net10:

Plotting Normal Quantile Graphs

Currently, you cannot plot normal quantile graphs using the stand-alone mode of the Virtuoso Visualization and Analysis XL tool. You can plot normal quantile graphs only for the Monte Carlo results from the Results tab of the ADE XL window.

Saving and Loading Graphs

You can save a graph to a file for future use. When you save a graph, the graph settings, such as zooming and panning, changing font type and font color, setting labels for X and Y axis, or changing the trace color are also saved with the graph file. As a result, you save on the effort required to customize the graph when you display the same graph again.

When you load the saved graph in a window and append a trace to that window, the new trace is displayed with the same window attributes.

If you open a new graph in a subwindow, the graph appears in the default graph attributes.

This section includes the following topics:

Saving a Graph

The graph is saved as an XML file with the .grf extension. The following information is saved with the graph:

Save a group of windows with the file extension .grf.group.

To save a window, plot a signal in the window and do the following:

Loading a Graph

Perform the following steps to load a graph that you have saved.

  1. Choose File – Load Window, or press Ctrl+L.
    The Load Graph Window to File form appears.
    In the Look in field, select the directory in which the .grf file that you want to open exists.
    Select the Specify new results database check box and click the Browse button to load the same .grf file, either with the original data or different data.
  2. Now, do one of the following:
    • Select the graph file you want to open from the list box below the Look in field.
    • In the File name field, type the name of the file you want to open.
    • Select the .grf extension to display the graph files and grf.group file extension in the Files of type drop-down list box to select a graph file group. The extension for graph files is specified by the filesuffix variable in the .cdsenv file.
    • Select the Specify new results database check box to plot the saved graph from a new results directory. Also, specify the name of the results directory from which you want to plot the graph. Ensure that the signal plotted in the saved graph exists in the results directory you specified.
      When you use this option, the saved graph is updated with the data from the new results directory and all the trace settings that you have applied to the saved graph are also retained. Hence, saved graphs can be used as a template when you reload a graph.
  3. Click Open.
    The saved graphs are displayed in a new window. This graph has all the attributes that you saved with the graph.
    If you have multiple windows open, loading a new window does not affect these windows.

You can also type the following command in the terminal window to load the graph saved in a graph state file (.grf).

viva -load_graph myGraphs.grf

Saving a Graph as an Image

If you save the graph as an image, the active graph or subwindow is saved with the trace legend area. You can insert the graph image into a document or print it.

You cannot load a graph image in a window.

The Virtuoso Visualization and Analysis XL tool provides several image formats to support a variety of applications and environments. While all image formats are functionally equivalent to binary storage formats, the size of a typical file varies greatly according to the format chosen. For example, a simple graph saved in the PNG format is typically less than 100 KB, while the same file saved in the TIFF or BMP format may exceed 1MB.

Perform the following steps to save a graph as an image file.

  1. Plot a signal in a graph.
  2. Choose File – Save Image
    The Save Image form appears.
  3. In the Look in field, browse to locate the directory where you want to save the image file.
  4. In the File name field, type a name for the image file. You can also specify macros, $TRACE and $SUBWIN, in the filename. These are used to save image files with the trace names and subwindows names.
  5. In the Files of type drop-down list box, select the format in which you want to save the image file.
    By default, the file is saved in a format based on the file extension you specify. For example, if you type output.png, the file is saved in the PNG format. The image file can be saved with .png, .bmp, and .tiff (or .tif) file extensions. On the other hand, if you select PNG (Best compressed) and type output.tiff, the file is saved as output.png. Though PNG and TIFF files are compressed, there is no loss in image quality with these image formats.
    The graph image file can be saved in the following formats:
    • Windows Bitmap Format (*.bmp)
    • JPEG Format (*.jpg)
    • Portable Network Graphics (*.png)
    • Portable Pixmap Format (*.ppm)
    • Tagged Image File Format (*.tif)
    • X Pixmap Format (*.xpm)
    • Adobe PDF (*.pdf)
    • Scalable Vector Graphics (*.svg)

    The default file type is JPEG.
  6. To specify the format properties, click the Format Option button.
    The Format Options form appears. This form includes the following fields:
    A quality bar, ranging from 20–100, is displayed under the JPEG Options section. Move the slider to the right or to the left to increase or decrease the quality of the graph image being saved. This quality bar is activated only if the file type is JPEG.
  7. In the Save section, select the following fields:
    • Selected subwindow only—Select this button if you want to save only the selected subwindow.
    • All subwindows, using—Select this button if you want to save all the subwindows. You can use the drop-down list to specify whether you want to save subwindows in a single file or multiple files.
      If you choose to save subwindows separately in multiple files, ensure that you specify the following macros: $TRACE or $SUBWIN. Depending on the specified macro, the graphs in the subwindows are saved in different files named either by their trace names or subwindow numbers.
    • Render exactly as screen—Select this check box if you want to save the exact copy of graph as it is visible on the screen. This also saves all attributes of the graph as well as zooming and panning properties. When you select this option, the Graph Display section is disabled.

    This option saves only those strips that are visible on the active graph. If you do not want to save a strip, you can adjust the graph window size to hide the strip.
  8. Resize Image(s)—Select this check box if you want to resize the image. In this section, you can change the following image attributes:
    • Width—Specify the width of the image.
    • Height—Specify the height of the image
    • You can select the units for the height and width from the drop-down list displayed at the right. The available units are pixels, inch, cm, mm, picas, and points. When you change the image units, the height and width values you have specified are automatically changed as per the selected units.
    • Resolution—Specify the resolution of the image. This field is unavailable if you select the image type in the vector format. Select the resolution type as pixels/cm or pixels/in from the drop-down list displayed at the right. When you change the resolution type, the height and width fields also change accordingly.
    • Maintain Aspect Ratio—The ratio of the width of the image to its height. Select this check box if you want to maintain the aspect ratio while modifying the height or width of the image.
    • Import Dimensions—Click this button to specify the default values for height, width and resolution.
  9. Graph Display—In the this section, specify the following fields:
    • Title—Select this check box if you want to display the graph title in the graph image
    • Legend—Select this check box if you want to display trace legend in the graph image.
    • Axes—Select this check box if you want to display axes in the graph image.
    • Grids—Select this check box if you want to display grids in the graph image.
    • Replace background color with:—Select this check box if you want to save the graph image in a different background color. You can specify a new color by clicking the button provided with this option. This option is not available when the file type is pdf and svg.
      All the above options are selected by default.
  10. Click Save.
    The graph is saved as an image file with the specified attributes.

When you do not specify a background color and save the graph as an image, the saved image may not be in readable form. For example, when you open the saved image by using an image viewer, such as GIMP, the graph appears as shown in the figure below:

You can use the GIMP image viewer and editor to convert the image into a readable format by performing the following steps:

  1. Choose Layer – New Layer.
    The New Layer form appears.
  2. In this form, select the Layer Fill Type field as Background color and click OK.
    The image is filled with the white background color.
  3. Choose Layer – Stack – Layer to Bottom. The image is now in readable format.

Reloading Graphs

Reloading a graph updates the already plotted traces with the latest simulation results based on the current in-context results directory. When you reload a graph, the settings that you have applied to a trace are also applied to the reloaded traces, such as, background color and font. For more information about the trace settings that are retained during reloading a graph, see Graph Settings Retained During Reloading.

You can reload a graph when you open the Virtuoso Visualization and Analysis XL tool in the stand-alone mode and also when you run the tool from ADE.

This section includes the following topics:

Reloading Graph When Opened in Stand-Alone Mode

In the stand-alone mode, you can reload an already open graph with the simulation results based on the current in-context results directory selected in the Results Browser.

Following are the examples that describe how reloading works in the stand-alone mode:

Example 1

Consider the following scenario in which you plot a trace from a results directory, change the in-context results directory, and reload the trace with the data from a new in-context results directory.

  1. Plot a signal, out, from an in-context results directory (simulation1) in a new window.
  2. Set the trace Style to Dot (as shown in the figure below). Notice that the time range of the out signal varies from 0.0 to 10 microseconds.
  3. Open another results directory, simulation2, which contains the simulation results for the same design.
  4. Set the database context to this new results directory, simulation2. For more information about how to change the in-context results directory, see Setting the In-Context Results Directory.
  5. Now, to reload the already plotted trace for the out signal from the previous results directory (simulation1) with the data from the new in-context results directory (simulation2), choose File – Reload – Current Subwindow.
    Alternatively, you can press Ctrl+R to reload graphs in the current window.
    The trace for the out signal is reloaded using data from the latest in-context results directory, simulation2, and all the trace settings are retained (as shown in the figure below). Notice that the time range of the reloaded trace now varies from 0.0 to 20 microseconds.
You can select the Reload using current context check box available on the Graph properties form to reload signals according to the data from the current in-context results directory. If this check box is not selected, signals are reloaded based on their individual databases. This check box is selected by default.

To reload the traces in all the subwindows, choose File – Reload – All Subwindows. All the traces for the common signals are updated with data from the current in-context results directory and all the trace settings are retained.

To reload the traces in all the windows in Virtuoso Visualization and Analysis XL, choose File – Reload – All Windows.

Example 2

You can also reload the traces for expressions created in the Calculator. Consider the following scenario in which you plot a trace for an expression, change the in-context results directory in Results Browser, and then reload the plotted trace with the data from the new in-context results directory

  1. In the Calculator, create an expression for the signal, out, from simulation1 results directory. The following expression is displayed: v("/out" ?result "tran").
    Simulation1 is the in-context results directory selected in the Results Browser.
  2. Apply flip function to this expression. The expression changes to: flip(v("/out" ?result "tran"))
  3. Now, evaluate this expression and plot the output in a new window. The following output trace is displayed:
    Notice that the time range of the output trace varies from -10 to 0.0 microseconds.
  4. In the Results Browser, change the in-context results directory to simulation2, which contains the simulation results for the same design.
  5. Choose File – Reload – Current Window.
    The trace for the expression you plotted earlier is updated with the data from the new in-context results directory (see figure below). The time range of the updated trace now varies from -20 to 0.0 microseconds.

If you create an expression for a signal from a results directory that is not set as the in-context results directory in Results Browser, the expression for this signal also displays the path of the results directory. For example,

v("/out" ?result "tran" ?resultsDir "./simulation_10/ampTest/spectre/config/psf")

This indicates that the database context of this signal is specified within the expression. When you plot the expression, it is always plotted with the specified results directory. The context for this expression does not change with the change in the in-context results directory in the Results Browser; and therefore, when you perform File – Reload on this trace, it is not updated with the new data.

Reloading Graph When Opened From Within ADE Explorer, or ADE Assembler

While working in ADE Explorer, or ADE Assembler, you can use the Refresh plotting option to update already open graphs with current simulation results. This option retains all the trace settings that you have applied to the traces in open graphs.

Important points to note:

To know more about refreshing graphs through ADE Assembler, see Refreshing Graphs in Virtuoso ADE Assembler User Guide.

To know more about refreshing graphs through ADE Explorer, see Refreshing Graphs in Virtuoso ADE Explorer User Guide.

Disabling Trace Reload

You can lock the database context of a trace to disable the trace reloading. You use this feature if you do not want to update the trace while reloading graphs with data from the in-context result directory.

The trace for which you lock the database context are not updated when you do File – Reload.

To disable the reloading of a trace, do one of the following:

Graph Settings Retained During Reloading

The Virtuoso Visualization and Analysis XL graph window saves and maintains the following settings for the graphs when you reload the graphs with the data from the latest in-context results directory:

How Marker Locations Change After Graph Reloading?

Printing Graphs

You can save a selected graph or all the graphs in the selected window to a file in PDF format, and then print the graphs on a network printer that you have installed on your computer.

Before you print, you can use the print preview mode to see how the graph will look after it is printed.

Perform the following steps to print a graph:

The table below contains a list of macro that you can specify:

Macro Description

$Title

Displays the window or subwindow title.

$TotalPages

Displays the total number of pages that are printed.

$DataContext

Displays the results directory for the plotted expressions and signals in the graph. This macro does not display the current in-context results directory in the Results Browser. If the signals from multiple results directories are plotted and then printed, specifying this macro in header or footer prints the name of all the databases that are used for plotting.

$UserID

Displays the user’s UNIX login name.

$Printer

Displays the name of the printer.

$Page

Displays the current page number.

$Date

Displays the date when the document is printed.

$DateTime

Displays the date and time when the document is printed.

$Author

Displays the full name user name.

$Time

Displays the time when the document is printed.
The upper-right corner of the PDF displays the time and date when the PDF is created.

Supporting Mixed Signals

You can use the Virtuoso Visualization and Analysis XL tool to plot analog and digital signals together in one window. Like analog traces, multiple digital traces can also be combined into a single strip. The digital signals are displayed in green by default.

To split the analog and digital signals into different strips, see Working with Strips.

If you want to work with analog and digital signals at the same time, you can plot analog and digital signals in the same window. The signals are plotted in the order they are selected in the Results Browser or ADE.

You can also drag an analog signal to place it in between two digital signals. The analog signal that you drag is displayed in a different strip. You can also impose an analog signal on a digital signal. In this case, the strip height for a digital signal is adjusted according to the height of the analog signal.

You can convert analog signals into digital signals and digital signals into analog signals, if required.

The Verilog and VHDL states are also displayed in specific colors to denote their strength and condition.

Loading Vector Files in Virtuoso Visualization and Analysis XL

Most digital simulators store the signal information in text files, such as VCD or VEC files.

Loading a VCD File

You can load a VCD file in Virtuoso Visualization and Analysis XL using the Select Waveform Database form. The selected file is loaded in the Results Browser and displays a folder, digital, as shown in the figure below:

The digital signals are plotted in the Results Browser as shown in the figure below.

To generate analog stimuli for this digital signal, you need to convert the digital signal into analog signal by using the Digital to Analog assistant that appears when you choose Measurements – Digital to Analog. Specify the form field values as shown in the figure below. For more information, see Converting a Digital Signal to an Analog Signal.

The .info file contains voltages, risetime, and falltime values and the VCD file contains the signal changes and the unit for time.

When you click OK, the CLK_25MHZ digital signal is converted into an analog stimuli signal, d2a_CLK_25MHZ.

Loading a VEC File

When you load a VEC file in the Results Browser, two folders, digital and analogStimulus are displayed, as shown in the figure below:

The analog stimuli files are automatically generated when you load a VEC file in Virtuoso Visualization and Analysis XL, whereas for VCD file, you need to perform an additional step to convert the digital signal to generate analog stimuli.

Loading Vector Files Using Command-Line Convertor

You can also use the command-line convertor, cdsConvertDigitalVector, to convert a VEC or VCD file into SST2 and PSF XL database that can be loaded into Virtuoso Visualization and Analysis XL.

Example: Converting a VEC File

Run the following command to call the convertor:

cdsConvertDigitalVector -i sig25mzN160mz_crt_analog.vec -o sig25mzN160mz_convert

where,

Now, when you open this converted database in the Results Browser, the digital and analogStimulus results directories are displayed. You can then plot the waveforms from these directories.

Example: Converting a VCD and .info File

Run the following command to call the convertor:

cdsConvertDigitalVector -i signal_crt_analog.vcd -vcd-info signal_analog.info -o stimuliDir

where,

Now, when you open this converted database in the Results Browser, the digital and analogStimulus results directories are displayed. You can then plot the waveforms from these directories.

Command-Line Options for File Convertor

The following options are available for the command-line convertor:

Option Description

-i [<vector-file>]

The VEC/VCD/EVCD vector file.

-o <data-directory>

The data directory for SST2 and PSF XL files.

[-vcd-info <info-file>]

A VCD signal .info file describing timing characteristics.

[-log <log-file>]

Write errors or warnings to named log file.

[-expand-bus]

Expand each bus into individual bits when writing to the SST2 database. By default, buses are not expanded.

[-bi-signals <in/out>]

Define bidirectional signals as input (default) or output.

[-exclude-stimulus-dataset]

Do not generate the analog stimulus dataset.

[-report <file>]

Generate a CSV report file describing each digital vector variable (analog or digital), full path, and direction, <rise>, <fall> ,<vil> , <vih>.

Converting an Analog Signal into a Digital Signal

In the stand-alone SKILL mode, you can create a digital representation of an analog signal.

To convert an analog signal into a digital signal, do the following:

  1. In the graph, select a trace and choose Measurements – Analog To Digital. You can select more than one analog trace at a time.
    The Analog to Digital conversion form appears. This form displays the name of the selected analog signals. The signals are displayed on the basis of their selection order; however, you can rearrange the order either by clicking the column header or by using the drag operation. The assistant has the following fields
  2. In the Logic Threshold field, select Single or High/Low.
    • If you select Single, you need to specify a Center value. Analog values equal to or greater than the specified center value are mapped to a digital value of 1. Analog values less than the center value are mapped to a logical value of 0.
    • If you select High/Low, you need to specify a high and a low threshold value. All analog values equal to or greater than the high threshold value are mapped to a digital value of 1. All analog values equal to or less than the low threshold value are mapped to a logical value of 0. The value Time to X puts a time limit on the interval that the signal may remain between the high and low threshold values before the signal is assigned a value of X.
  3. If you want to make a bus of digital signals from the analog signal, select the Make Bus check box.
  4. Then, select the radix type in the drop-down list and provide a bus name.
    The MSB (topmost signal) and LSB (signal at the bottom) values for the bus are indicated below the Bus name field.
  5. In the Plot Mode drop-down list box, select whether you want to append the digital trace to an existing graph, replace an existing graph with the digital graph, or add the digital trace to a new subwindow or new window.
  6. Click OK.

Converting a Digital Signal to an Analog Signal

In the stand-alone SKILL mode, you can also create an analog representation of a digital signal.

To convert a digital signal into an analog signal, do the following:

  1. In the window, select a digital trace and choose Measurements – Digital To Analog. You can select more than one digital trace at a time.
    The Digital to Analog Conversion form appears. This form displays the digital signals you select. The signals are displayed on the basis of their selection order; however, you can rearrange the order either by clicking the column header or by using the drag operation. The assistant has the following fields:
  2. In the Analog Values section,
    1. In the High/Low field,
    2. In the X field, specify the value to which state X of the digital wave is converted to. The X value may be given as a:
      • Number
      • Keyword vhi, vlo, or vprev, where
        vhi substitutes the X value with the value in the Analog Hi Voltage field.
        vlo substitutes the X value with the value in the Analog Low Voltage field.
        vprev implies that the previous (non-X) state, either vhi or vlo is used.
      • Simple expression, such as (vhi + vlo)/2
    3. In the Rise/Fall fields, specify the risetime and falltime.
  3. In the Bus Output as group box, select Voltage to return the selected bus as a single analog signal or select Bits to return the selected bus as a wave list, which is one analog wave for each bus bit. The field is available only if you select a bus.
  4. In the Transition group box, select Piece-wise-Linear to join the points in the analog waveform with straight lines or select Zero-T for voltage transitions in zero time.
    The Transition field is available only if the Bus Output in field is selected.
  5. In the Plot Mode drop-down list box, specify whether you want to append the analog trace to an existing graph, replace an existing graph with the analog graph, or add the analog trace to a new subwindow or new window.
  6. Click OK.

Generating Derived Plots

For transient periodic signals, you can generate the derived plots, such as frequency, duty cycle, and period that can be plotted against time.

Do the following to generate a derived plot:

Limitations

Plotting Histogram

To generate the histogram plot directly on a graph, do one of the following:

You can specify the following fields in this form:

The figure below displays a normal quantile plot:

Changing Histogram Trace Properties

To change the properties of the histogram plot, right-click the histogram trace and choose Trace Properties.

The RectAnnotationsTrace Properties for <histogram_trace_name> form appears.

Specify the following fields in this form:

  1. In the Name field, type the name for the trace or select the Default check box to display the default trace name. When you select the Default check box, the Name field becomes unavailable. The Name and Default fields are not available if you select more than one trace.
  2. In the Type/Style fields, do the following:
    • Specify whether you want to represent the trace by a line, points, histogram, bar, spectral, or sampleHold.
    • Specify whether you want the trace style to be Solid, Dashed, Dotted, or DotDashed, or DashDotDot.
      The trace style option does not work for Bars and Spectrum.
    • Specify whether you want the trace to be Fine, Medium, Thick or ExtraThick.
      The trace thickness option does not work for Bars and Spectrum.
    • In the Symbols field, select the Show check box to display data points on the trace and select the symbol type from the drop-.down list.
    • In the Annotations field, select the following check boxes to display annotations:
      • Density Estimator— Select to display density estimator curve.
      • StdDev Lines— Select to display standard deviation lines.
      • % Markers— Select to display markers.
      • Skewness— Select to display skewness calculation in the graph label of the histogram trace.
      • Kurtosis— Select to display kurtosis calculation in the graph label of the histogram trace.
      • Jarque-Bera— Select to display normality calculation based on Jarque-Bera test in the graph label of the histogram trace.
  3. In the Color field, select the foreground color for the trace. Alternatively, you can also set the trace color by right-clicking the trace and selecting Color.

Working with Buses

A group of digital signals can be converted to a create a bus. You can expand a bus to view its component signals.

If you want to create a bus of analog signals, you need to convert the analog signals to the corresponding digital signals. For information about how to convert an analog signal to the corresponding digital signal, see Converting an Analog Signal into a Digital Signal. After the conversion is complete, you can create bus from the digital signals.

To combine the signal conversion and bus creation processes in a single step, you can select the Make Bus check box in the Analog to Digital conversion form, and specify a bus name while converting the analog signal to a digital signal.

Creating a Bus

To create a bus:

  1. In a graph window, select the digital traces that you want to use to create a bus.
  2. Choose Trace – Bus – Create.
    The Create Bus form appears.
    The Signal/Expr Names section in this form displays the selected traces, which you use to create the bus, in the order of significance (top to bottom—from the least significant bit (LSB) to the most significant bit (MSB)). However, you can rearrange the trace order either by clicking the column header or by using the drag operation.
  3. Now, in the Create Bus form, do the following:
    1. Type a name for the bus in the Bus Name field.
    2. Select the Radix for the bus, such as Ascii, Binary, Hex. Alternatively, to change the radix type after a bus is created, right-click the bus and choose Radix.
    3. Specify whether you want the bus to be appended to the digital traces in the graph or to replace the selected traces in the Plot Mode field.
    4. Click OK.
      The MSB and LSB values are indicated at the end of the Create Bus form.

      The bus is created from the selected digital traces.

There are three states in which a signal can exist in the bus—Hi, Lo, and XZ, where X is a transition from Lo to Hi and Z is a transition from Hi to Lo. Following is the color pattern for the traces in a bus that belong to a particular state:

If you want to create a bus of analog signals, convert them to digital signals by using the Analog to Digital assistant. Then, follow the above mentioned steps to create the bus.

Plotting Parametric Buses

You can plot parametric digital buses or bus bundles, which are families of buses containing sweeps or corners, using the Results Browser or CIW. The digital buses can also be plotted from ADE when you right-click the signal icon in the Results tab and choose Plot or Plot Across Corners.

The figure below displays a parametric bus, /out1<0:2>, where all leaf waveforms (for each sweep or corner) are plotted in a single strip. Analog buses are always plotted in a tree structure with the root displayed at the top, and when you expand the root, the leaf waveforms appear in the legend and graph.

Notice that the legend of a digital parametric bus lists the corner and design variables. When you send the bus waveforms from the Calculator or graph to ADE, the root expression is generated and displayed in the Outputs Setup pane of ADE.

You can also perform calculations on bus waveforms using the following Calculator functions:

You can also set the useD2A environment variable to determine how the calculation results are represented for digital buses and whether output results are to be converted from digital to analog.

Creating a Mnemonic Map

You can create a mnemonic map and add rules to set up how different bit patterns and values of a bus are mapped with specific colors and formats by using the Configure Mnemonics form.

To create a mnemonic map:

  1. In the trace legend area, right-click a bus and then choose Display – Mnemonic – Configure Mnemonics.
    The Configure Mnemonics form opens.
  2. Click Add Mnemonic Map to create a mnemonic map.
    A mnemonic map is created and displayed in the left pane of the form. By default, mnemonic maps are named as New map #1, New map #2, New map #3, and so on. You can assign a different name to the map by editing the Name field.
    A default rule is also added to the mnemonic map.
  3. Edit the default rule by specifying the following information:
    1. In the Radix column select a radix. For example, 'h (Hexadecimal).
    2. In the Values Matching column, enter a value that you want to map in the format of the selected radix. For example, 5.
    3. In the Relabel As field, enter the ASCII string you want to associate with the value. For example, Power.
    4. The Preview field shows how the specified bit pattern or value will look like in the bus. You can change its appearance by using the format editing area below the mnemonic map definition, as follows:
      • Line: Specify the color and shape of the lines drawn around the value.
      • Fill: Specify the color and pattern of the filled area within the lines.
      • Text: Specify the color and font style of the mnemonic text.
      • Icon: Specifies the icon to display to the left of the mnemonic text.
  4. Click Add Rule to add another rule. Edit the rule by specifying the Radix, Values Matching, Relabel As, Line, Fill, Text, and Icon fields.
  5. Click Save Rules to save the mnemonic map.
  6. Right-click the bus and then choose Display – Mnemonic – Name of the Mnemonic Map to apply the mnemonic map to the bus.
    The mnemonics are applied to the bit patterns or values according to the rules defined in the mnemonic map.
You can watch a video demonstration on how to work with mnemonic maps at Usability Enhancements in Digital Signals. You can also read the related blog at Virtuoso Video Diary: Usability Enhancements in Digital Signals.

Applying a Mnemonic Map to a Bus

To apply a mnemonic map to a bus:

  1. In the trace legend area, right-click a bus and then choose Display – Mnemonic to open the context menu command.
    A list of available mnemonic maps is displayed.
  2. Select the mnemonic map that you want to apply to the bus.
    The mnemonics are applied to the bit patterns or values according to the rules defined in the mnemonic map.
    To disable the mnemonic map, right-click the bus and choose Display – Mnemonic – Disable Mnemonics.

Importing Mnemonic Maps from SimVision

If you have created a mnemonic map in SimVision, you can import it using the Import From SimVision command on the Configure Mnemonics form.

To import a mnemonic map from SimVision:

  1. In the top-right corner of the Configure Mnemonics form, click Import From SimVision.

    The Select the SimVision commands script file to open form appears.
  2. Select the SimVision commands file of .svcf format from which you want to import the mnemonic map created in SimVision.
  3. Click Open.
    The Configure Mnemonics form is updated to show the mnemonic maps defined in the SimVision commands file.
  4. Select a mnemonic map that you want to apply. You can also edit rules defined in the selected map. For example, you can edit the values of Radix and Values Matching according to data in the bus to which you are applying mnemonic map.
  5. Click Apply and then click OK.
    The bus is updated according to the rules defined in the mnemonic map.

Setting Bus Properties

To set the properties of a digital bus, right-click the bus name and choose Digital Bus Properties.

The Digital Bus Trace Properties for Bus_Name form appears.

This form displays the following information:

Expanding a Bus

After you add a bus trace to the window, you can expand the bus to display the digital traces contained in the bus into individual strips.

To expand a bus, select the bus you want to expand and do one the following:

Collapsing a Bus

To collapse an expanded bus, select the bus you want to expand by selecting the bus name in the trace legend area and do one of the following:

Exporting a Bus

To export the data from a bus signal into a CSV file, do the following:

Sending a Bus Signal to Calculator

To send a bus signal to Calculator, do the following:

Consider an example in which you convert an analog signal to digital using the Analog To Digital assistant, then create the bus from the converted digital signal, and finally send the bus signal to Calculator, the following expression is created in the Buffer:

awvCreateBus("Test_bus" list(awvAnalog2Digital(v("net10" ?result "tran") nil nil 2 nil "centre") ) "Binary")

Here, awvAnalog2Digital(v("net10" ?result "tran") nil nil 2 nil "centre" indicates that the net10 analog signal has been converted to a digital signal.

Sending a Bus Signal to Table

To send the bus signal to Table, do the following:

Working with Markers

A marker attaches a description to a point on the graph. The default label for a marker displays the X and Y coordinates of its intersection with the trace—if it is attached to the trace—or the coordinates of the point location of the marker. You can associate an expression with a marker label. The expression is evaluated when you place the marker on the graph and updated when you choose File – Reload.

If you use the replace mode to plot signals obtained from the simulation runs on the same design, the signals are updated with the new data and the expressions are re-evaluated.

Markers are of the following types:

This section includes the following topics:

To lean the various tips, tricks, and shortcuts that you can apply while working with markers in Virtuoso Visualization and Analysis XL, see the Tips and Tricks: Markers video on Cadence Online Support.

In addition, you can read the Tips and Tricks on Virtuoso Visualization and Analysis XL Markers blog.

Adding Markers

You can add point, vertical, horizontal, and delta markers to a trace. The circular markers can be added to circular graphs that are obtained from AC analysis, Smith Charts, and polar plots.

To add markers to a trace, do the following:

Refer to the below sections to know how to add different markers:

Adding Markers with Marker Toolbox

To add a vertical, horizontal, point, or reference point (ARefPoint or BRefPoint) marker with the help of the Marker Toolbox, do the following:

The Marker Toolbox assistant appears to the left of the window. It includes tools that you can use to add the required type of markers. To create a marker, drag the desired marker to the specific location where it needs to be placed.

Marker Labels

Depending on the information you want to display in the marker labels, you can specify different format strings in the Label field. These formats are evaluated and inserted into the string when you place or edit a marker. As a result, labels can reference properties, such as marker coordinates, trace slope, trace name, and so on, or the result of a scalar expression.

Each marker label displays the default value set in the defaultLabel .cdsenv variable.

The following table describes the various format strings that can be specified using the Label field.

Marker Label Description

%M

Marker name

%X

X-coordinate

%Y

Y-coordinate

%h

History name

%t

Test name

%c

Corner name

%d

Dataset name

%x

Second X-coordinate for delta markers

%y

Second Y-coordinate for delta markers

%W

Delta value on X-axis (Δx)

%H

Delta value in Y-axis (Δy)

%S

Slope (Δy/Δx)

%N

Name of the trace

%E

Evaluated value of the expression

%F

Frequency value

%D

Absolute path to the results directory from where the signal is plotted

%i

Index value of the nearest data point on the trace
For Circular Graphs

%C

Real and imaginary Cartesian values

%Z

Impedance values, such as resistance and reactance

%A

Admittance values, such as conductance and susceptance

%R

Reflection coefficients, such as mag and angle

%P

Polar values, such as mag and angle

%F

Frequency value, which includes the independent axis data

%D

Absolute path to the results directory from where the signal is plotted

Editing the Marker Label of a Point Marker

To edit the marker label of a point marker:

  1. Right-click a point marker and choose Point Marker Properties.
    The Point Marker Properties for Marker Name form opens.
  2. Click the Edit button, which is displayed next to the Label field.
    The Editing Marker Label form opens. The format specifiers displayed in this form depend on the type of graph and marker.
  3. In the Label Format field, type the format specifiers that you want to display in the marker label.
    Alternatively, you can select or deselect the check boxes next to the format specifiers that you want to add or remove from the marker label.
    You can also click the icon to clear the values set in the Label Format field. You can click Reset to reset the Label Format field to the last saved value.
  4. From the Insert options:
    1. Click Selected to add the currently selected format specifier to the Label Format field.
    2. Click Space to add a space between two format specifiers.
    3. Click New Line to add a newline character (%n) between two format specifiers.
  5. Click OK to save the changes and close the Editing Marker Label form.
    The values set in the Label Format field are automatically updated in the Label field on the Point Marker Properties for Marker Name form.

Related Topics

Marker Labels

Adding a Point Marker

Adding a Point Marker

Adding a Fixed-Y Marker

A fixed-y marker is a special type of point marker that is attached to the trace at the specified y-axis value. You can drag this marker to other traces in the same graph window or subwindow to create another fixed-y level marker at the same y-axis value.

You can also choose to display a y-level indicator for a fixed-y marker when it is selected. Use this indicator to drag the fixed-y marker vertically, which makes it easy to change the y position of the marker.

To add a fixed-y marker:

  1. From the menu bar of Virtuoso Visualization and Analysis XL, choose Marker – Create Marker.
    The Create Graph Marker form opens.
  2. Click the FixedY tab and specify the following fields:
    • In the Label field, specify the format specifiers whose corresponding information you want to display in the label of the fixed-y marker.
    • In the Expression field, specify the expression whose evaluated value you want to display in the marker label. For example:
      average(v("out" ?result "tran-tran") )
    • From the Trace drop-down list, select the trace to which you want top attach the fixed-y marker.
    • Select the Show Marker Level when Selected check box to display a y-level indicator when the FixedY marker is selected. You can drag this y-level indicator to drag the marker vertically.
    • In the Y Position field, specify the y-axis value at which you want to create the fixed-y marker.

You can also use the bindkey Shift + Y to create a fixed-y marker.

Related Topics

Create Graph Marker Form

Adding a Horizontal Marker

Adding a Vertical Marker

Adding Vertical and Horizontal Markers on Point Marker Location

You can add a vertical or a horizontal marker at the same location where a point marker is placed.

To add a vertical marker, right-click the point marker and choose Create Vertical Marker.

To add a horizontal marker, right-click the point marker and choose Create Horizontal Marker.

Adding an Edge Marker

The following figure shows a point, vertical, and horizontal marker.

Adding Markers with Bindkeys

To add a marker with the help of bindkeys, do the following:

  1. Click a point on the graph where you want to place a marker.
  2. Press one of the following keys:
    • M—Adds a point marker
    • H—Adds a horizontal marker
    • V—Adds a vertical marker

    A marker is placed on the trace based on the bindkey you use.

Adding a Period Marker

The Period Marker measures the distance between the selected edge and its adjacent rising or falling edge. By default, this measures the threshold mid-point distance between the two edges. You can use the marker context menu options to change the start and end measurement points for each edge. For example, you can measure from the high threshold of the first edge to the low threshold of the end edge. When you create a period marker, if required, the edge markers are added and connected with a standard delta marker. For more information about this marker, see Transient Measurement Assistant.

Adding a Dx/Dy Marker

The Dx/Dy marker is a standard delta marker with end points initially placed at the low and high threshold intercept points of a single edge. After this marker is created, you can perform all the delta marker operations on it. The dx/dy marker does not change with the change in the edges. For more information about this marker, see Transient Measurement Assistant.

Adding a Delta Marker

Delta markers are used to mark the difference between two points in a graph. A delta marker joins two point markers in the same or different traces. To place a delta marker you must first place a point marker or select one. Delta markers can be moved or deleted independent of their point markers. For information about how to work with a delta marker, see Working with Delta Markers.

Repositioning Marker Labels

You can drag and move the labels attached to the horizontal and vertical markers. To bring the marker labels back to their original position, right-click the horizontal, or vertical markers and choose Reposition Intercept Labels.

After moving labels attached to the point, reference points (A/B marker), delta, and circle markers, you can bring the marker labels back to their original position by right-clicking the point marker and choosing Reposition Labels.

Setting Marker Properties

To view or change the properties of markers, do one of the following.

Setting Properties for Point Markers

The following fields are displayed for setting the properties of a point marker:

Setting Properties for Horizontal and Vertical Markers

To change the properties for horizontal or vertical marker, do one of the following:

The following fields are displayed for setting the properties of a horizontal or vertical marker:

Setting Properties for Spec Markers

To view or change the properties of spec markers, right click the corresponding trace and choose Spec Properties.

The Spec Marker Properties for Specification form is displayed, as shown in the following figure:

In this form, you can edit the following properties:

If a graph contains multiple traces, spec marker properties cannot be changed for an individual trace. Changes in spec marker properties are applicable for all the traces of a graph.

Snapping Markers

You can snap markers to analog and digital traces. In analog traces, you can also set the criteria based on which you want to snap markers, where as digital markers can be snapped only to the edge transitions, low to high and high to low. If the marker extends beyond the display area, the marker is panned automatically.

For digital traces or buses, the vertical, delta, and point markers can be snapped and for analog traces, the horizontal, vertical, delta, and point markers can be snapped based on the snapping criterion.

To set the snapping criteria to snap the markers to analog traces in the window, do the following:

  1. Select a maker and choose a snapping criterion from the drop-down list box displayed on the snap toolbar based on which you want to snap the marker. For example, local maxima, local minima, and so on. By default, Data Point is selected in the drop-down list box.
    When you add a vertical or horizontal marker on a trace, the Value field displays the X-axis location of the selected marker. This field is updated automatically if you move the marker.
  2. Specify a value for the selected snap criterion by which you want to snap the marker.
  3. Then, to snap the marker to the next and previous snap points, do one of the following:
    • On the Snap toolbar, click the Next Edge and Previous Edge buttons.
    • Right-click the selected marker and choose Next Edge and Previous Edge respectively. These options are not available in Horizontal marker context menu.
    • Press the N or P bindkeys to move to the next or previous edges, respectively.

    The selected marker is snapped based on the snap criterion you selected. For example, if you select Local Maxima as the snap criterion, the marker is shifted to the maxima value (peak) local to the curve when you click the Next Edge button.
    You can select any one of the following snap criterion:
    • Local Maxima—Defines the transition point when there is a change in the slope from the rising to falling edge starting from the marker’s current position. The local maxima is calculated as the change in slope from rising to falling edge starting from the current marker position and the transition point is known as the local maxima.
    • Local Minima—Defines the transition point when there is a change in the slope from the falling to rising edge starting from the marker’s current position.
      At any point, the double derivative of a waveform should be zero to find the local maxima or the local minima. Local Max or Min—Defines that the snap point can be either local maxima or local minima.
    • Specific Y Value—Defines the snap point of the marker to a specific Y-axis value.
    • Specific X Value—Defines the snap point of the marker to a specific X-axis value.
      This snap criterion works for all types of markers except the horizontal markers.
    • Data Point—Defines that a specific data point on the curve should be considered as the snap point. This is the default snap criterion.
    • Global Maxima—This snap criterion is similar to local maxima. The only difference is that it applies the snap settings to the global maxima or positive peak.
    • Global Minima—This snap criterion is similar to local minima. The only difference is that it applies the snap settings to the global minimum value.

If you want to use the same snap criterion to snap a marker to more than one analog trace, select the maker and then hold down the Ctrl key and click the analog traces. Next, click the Next Edge or Previous Edge button to snap the marker to the snap points on the selected traces.

To snap digital markers, select the digital marker and click the Next Edge and Previous Edge buttons on the Snap toolbar.

For more information about snapping point markers and reference point markers on circular graphs, see Snapping Markers on Circular Graphs.

Customizing Markers

This section includes the following topics:

Displaying Intercept Data for Markers in Marker Tables

Vertical Marker Table

To display the vertical marker intercepts, do the following:

The Vert Marker Table assistant appears at the bottom of the window, displaying all vertical marker intercepts for each trace. When you add a vertical marker on a trace, the vertical marker intercepts for all the traces are displayed in the marker table.

In the vertical marker table, rows display the trace names and columns display the intercept points of each vertical marker.

The active vertical marker intercepts for each trace are also displayed in the trace legend area.

If you create a delta marker between two or more vertical markers, the vertical marker table includes an additional column to display the vertical marker delta values on traces (as shown in the figure below).

You can create a delta marker between two vertical markers by using one of the following methods:

The delta value displayed in the vertical marker table is always an absolute value.

If you do not want to display delta values in the vertical marker table, right-click the delta line joining two vertical markers and choose Diff Visible.

You use the horizontal marker table to view the trace intercepts for all the horizontal markers in a table.

Horizontal Marker Table

To display the horizontal marker intercepts in a table, do the following:

When you zoom-in a graph, the horizontal marker table lists only those intercepts that are visible in the zoomed-in portion of the graph. The horizontal marker table is updated only when you move the marker.

If the graph includes multiple Y-axes, do the following to change the axis of the horizontal marker:

Horizontal marker now shows intercepts for the traces that are attached to the axis you select. The marker table is also updated with the new intercepts.

Exporting Markers

To export the vertical marker intercept data in a CSV file, do the following:

To export the horizontal marker intercept data in a CSV file, do the following:

Deleting a Marker

To delete a marker, do one of the following:

To delete all markers on a trace, select a marker and do one of the following:

To delete a AB delta marker, you can right-click any of the two point markers or the delta marker line and choose Delete. The A and B markers in the delta marker are deleted.

Editing a Marker

The default marker attributes are controlled by the values assigned to variables in the .cdsenv file. For more information, see Appendix A, “Virtuoso Visualization and Analysis XL Tool Environment Variables.”

To edit a marker, double-click the marker. The Marker Properties form appears. Edit the required fields in this form. For more information about the fields, see Setting AB Delta Marker Reference Point Properties.

Moving a Marker

To move a point marker, drag the point marker anywhere on the trace.

To move a vertical marker, place the pointer on the vertical marker. When the pointer becomes a bidirectional arrow, drag the pointer along the X-axis to move the marker. Similarly, drag a horizontal marker along the Y-axis to move the marker.

Zooming a Marker

You can zoom in a graph and add a point marker on the zoomed in region of the graph. Now, when you zoom out, if the data point where you created a marker is out of the current screen, the marker may not place correctly and move out of the screen range.

The data point which is out of the current screen is always closer to a data point inside the current screen, because the X range is much smaller than the Y range. Virtuoso Visualization and Analysis XL looks for the closest data point among all data and not the data on the current screen.

Consider the following example in which you zoom in to the range from 450ns to 500ns and then move the pointer to (480ns, 0.4V) and then add a point marker. This marker is placed at (274ns, 0.0081V) because data points on screen are (482ns, 0.00464V) (472s, 0.00453V), and so on. Notice (480ns, 0.4V) is closer to (274ns, 0.0081V) than the data points on the screen.

Working with Delta Markers

Delta markers are used to mark the difference between two points in a graph. A delta marker joins two point markers in the same or different traces. To place a delta marker you must first place a point marker or select one. Delta markers can be moved or deleted independent of their point markers.

You can move either end of a delta marker; X and Y coordinates are updated accordingly. You can use delta markers to measure delays or use them with the min and max functions to measure peak-to-peak values.

This section includes the following topics:

Adding Delta Markers

You can create delta markers between two or more point, vertical, and horizontal markers on one or more traces. You can also create delta markers between two different marker types. For example, you can create delta marker between point markers and vertical markers.

Following are the two methods that you can use to create multiple delta markers on a trace:

Method 1:

  1. Add two or more point markers. To know how to create a point marker, see Adding a Point Marker.
  2. Select all the point markers by holding down the Ctrl key and do one of the following:
    • Press the bindkey Shift+D.
    • Choose Marker – Create Delta Marker.

    The delta markers are created between all the selected point markers. The method can be applied to create delta markers between any combinations of point, vertical, and horizontal markers.
You can add point, vertical, horizontal, delta, and AB markers in the eye diagram and spectrum plots. However, when you add a vertical or a horizontal marker in the eye diagram, the intercepts are not displayed in the plot.

Method 2:

  1. Create a point marker. To know how to create a point marker, see Adding a Point Marker.
    The point marker you created remains selected.
  2. Place the mouse pointer on the trace where you want to create the second marker. You can create delta markers on multiple traces.
  3. Press the bindkey D.
    A new point marker is created at the same point where you placed the mouse pointer and a delta between this new marker and the previously created point marker is also created. This new marker is of the same type as the marker type of the previously selected marker. For example, if you created a point marker in step1, the new maker created after step2 is also a point marker.
    You can repeat this method to create delta markers between multiple point markers. The last marker that you create remains selected.
    Repeat steps 2-3 to create delta marker between two or more vertical or horizontal markers.
    If the two markers in a delta marker have the same Y-axis units, the delta marker label displays the dx, dy and slope values. On the other hand, if the Y-axis units are different, the delta marker label displays only the dx value.

Moving a Delta Marker

To move a delta marker, you can set the snap criterion on a point marker in the delta marker. You can then use the Next Edge and Previous Edge buttons to move the selected point marker in the delta marker.

Adding AB Marker

AB marker is a delta marker of XY type and displays the dx, dy, and the slope values. Do the following to add an AB marker to the trace with the help of bindkeys:

  1. Move the mouse pointer to a location on the trace where you want to create an AB marker.
  2. Press A.
  3. Move the mouse pointer to another point on the trace to specify the second location for the delta marker.
  4. Press B.
    A delta marker of XY type appears on the graph. If one of the traces is a digital trace, the delta marker label displays only the dx value.
    You can add multiple AB markers by repeating these steps.
To convert an AB delta marker into a delta marker, right-click the delta marker line and choose Convert A/B Marker to Delta.

Displaying Marker Labels in Delta Markers

To show or hide the marker labels for the point markers in a delta marker, do one of the following:

Setting AB Delta Marker Reference Point Properties

To view or change the properties of an AB reference point marker, do one of the following:

Deleting Delta Markers

To delete the delta marker, right-click the line joining two point markers and choose Delete. All the delta markers are deleted.

To delete a particular set of delta marker, right-click the point marker which you want to delete and choose Delete. The selected point marker and the delta marker joining the point marker are deleted.

Editing Delta Marker Properties

To view or change the delta marker properties, do the following:

Working With Edge Markers

Edge Markers are special markers that can be attached to the rising or falling edges of a trace to measure the transient properties of the selected edge. The figure below displays an edge marker placed on the rising edge of a trace. The marker label displays the risetime value for this edge. If you place the edge marker on the falling edge of the trace, the marker label displays the falltime value for that edge.

The figure above also displays the Edge Browser at the bottom of the strip that you can use to view and analyze the various edges in the trace. By default, the Edge Browser is hidden in the graph. For more information about how to use Edge Browser, see Using Edge Browser.

This section includes the following topics:

Creating an Edge Marker

You can create an edge marker by using one of the following methods:

Setting Edge Marker Properties

Do the following to set the properties for the edge markers:

This form includes the following fields:

Edge Marker Context-Sensitive Menu

Right-click the edge marker to use the various options listed in the context-sensitive (shortcut) menu. The following figure displays the available menu options:

The shortcut menu options are explained as below:

Creating a Delta Marker between Edge Markers

To create delta markers between two or more edge markers on a single or multiple traces, perform the following steps:

  1. Create an edge marker using the bindkey t and then select this edge marker.
  2. Place the pointer close to a rising or falling edge on the same or another trace and press the bindkey d.
    A new edge maker is created at the selected point and a delta marker is created between the two edge makers. You can also select more than one markers and repeat these steps to create further edge markers and delta markers.

Alternatively, to create delta markers between two or more edge markers on a single or multiple traces, perform the following steps:

  1. Create an edge marker on the first trace using the bindkey t.
  2. Create an edge marker on the second trace using the bindkey t.
  3. Now, select both the edge markers using Ctrl+click and press Shift+D.
    A delta maker is created at between the selected edge markers.

Working with Circular Graphs

You can display complex data values from AC analysis in the form of Smith charts and polar plots. The Smith chart shows the unity circle that is R = 1 circle, the resistance circles, and the reactance circles.

This section includes the following topics:

Creating a Circular Graph

To create a circular graph, do the following:

  1. Open a results directory in the Results Browser, and then open the ac-ac analysis directory.
    The Graph Type drop-down list appears on the Results Browser toolbar.
  2. Select a graph type from this list. The available graph types are—Default, Rectangular, Polar, Impedance, Admittance, Immittance, and RealvsImag.
    • To create a polar plot, select the Polar graph type.
    • To create a Smith chart, select either Impedance, Admittance, or Immittance graph type.
  3. Plot a signal in the selected destination. For more information about how to plot a signal, see Plotting a Signal from the Results Browser.
    The circular graphs can be of two types—Smith charts and polar graphs. The Smith chart can further be of three types—Impedance Smith Charts (Z Smith), Admittance Smith Charts (Y Smith), and Immittance Smith Charts (Combined Z Smith and Y Smith). The circular graph of type Z Smith is displayed in the figure below.

Polar Plot:

Type of Smith Charts

You can use the bindkey O to switch between the Impedance, Admittance, and Immittance Smith Charts.

After a Smith chart is plotted, the following sections are displayed in the trace legend area on the left:

The default scale attributes for circular graphs are controlled by the values assigned to the variables in the .cdsenv file. For more information, see Appendix A, “Virtuoso Visualization and Analysis XL Tool Environment Variables.”

If you plot circular graphs that have the same plot type, the circular graphs are plotted in the same subwindow. For example, two Y-Smith or two Z- Smith can be plotted in the same window. However, if you plot graphs from different plot types, the graphs are plotted in a new subwindow. For example, Y-Smith and Z-Smith are plotted in two different subwindows.

Tracking Cursor

The tracking cursor displays the trace name, trace color, and frequency of the point you that you select or point to on the circular graph. For a Smith chart, the tracking cursor also displays the real and imaginary values. However, for polar plots, the tracking cursor displays the magnitude and angle, instead of the real and imaginary values.

The rest of the circular graph values are displayed dynamically in the various sections in the trace legend area.

To show or hide the tracking cursor:

  1. From the menu bar of Virtuoso Visualization and Analysis XL, choose Marker – Tracking Cursor.
  2. Right-click anywhere in the graph and choose Trace Marker Always Visible.

You can also set the traceMarkerDisplay .cdsenv variable to display values for the tracking cursor, which is also called a trace marker. The following formats are supported to display the trace marker values:

The trace marker or tacking cursor is always visible on the graph only if both the Tracking Cursor and the Trace Marker Always Visible commands are enabled.

When the Tracking Cursor command is enabled but the Trace Markers Always Visible command is disabled, the trace marker is displayed only when you point the mouse pointer onto the trace.

With the Tracking Cursor command enabled, if you enable the Trace Marker Always Visible command again, the trace marker remains visible at its last location on the trace even if the mouse pointer is away from the trace.

Displaying Symbols on Circular Traces

To display symbols on a circular trace, do one of the following:

In this form, select the Turn On Symbols check box to display symbols on the trace. By default, the symbols are displayed for all trace points. To display symbols for a given number of trace points, specify the count in the Points per Symbol field.

After turning on the symbols, you can select the symbol type by doing one of the following:

You can also set the dependent modifiers for an AC or a complex dataset, such as Magnitude, dB10, dBm, and dB20. See the Setting Dependent Modifiers for a Complex Trace for more information.

Adding Markers on Circular Graphs

You can add reference, point, circular, and delta markers on circular graphs. By default, the markers in the circular graphs are always visible. To hide the markers, you can set the tracemarkeralwaysvisible .cdsenv variable to false.

Adding a Circular Marker

To add a circular marker on polar plots or Smith graphs,

  1. Choose Marker — Create Marker.
    The Create Graph Marker form appears.
  2. Open the Circular tab. The form fields corresponding to circular marker appear, as shown in the figure below.
  3. Specify the following fields:
    • Label—Specify a label for the marker. See Marker Labels for more information.
      If you do not enter text in the Label field, the X and Y coordinates of the marker are displayed.
    • Position—Type the real and imaginary values (x+ij) where you want to add the circular maker. Alternatively, you can select a point on the graph where you want to add the circular marker. The real and imaginary values of the point you select are automatically added in the Position field.
    • Radius—Specify the radius (magnitude) of the circle.
    • Description—Specify an additional information about the circular marker. The description text is displayed when you move the pointer on the marker.
    • Color—Specify the marker outline and fill color.
  4. Click OK.
    The circular marker according to the specified values is created on the circular graph.

The figure below shows an example of the circular graph added on a polar plot.

Adding a Smith Reference Point Marker

To add a Smith reference point maker on a circular graph, select a point on the trace and press the bindkey R. The reference maker is created from the center to the selected point. The readout for the reference point marker—Real + Imag, Gamma, Zd, Yd, and VSWR—is displayed in the Reference point values section in the trace legend area.

You can add multiple reference markers on the circular graph. When you select a reference marker, the reference point values and graphical measurements change based on the circles and annotation for the selected reference point.

Setting Smith Reference Point Marker Properties

To set the reference marker properties, right-click a reference marker and choose Smith Ref Point Properties. The Smith Reference Point Marker Properties for <marker_name> form opens.

The Smith Reference Point Marker Properties for <marker_name> form includes the following fields:

Adding a Point Marker

To add a point marker, do one of the following:

Setting Point Marker Properties for a Circular Graph

The following fields are displayed for setting the properties of a point marker for a circular graph:

Adding a Circular Marker

To add a circular marker, do the following:

The Create Graph Marker form appears. On the Circular tab, in the Position field, specify the real and imaginary values for the circular marker. In the Radius field, specify the radius. For more information about the circular marker fields displayed in the Create Graph Marker form, see Adding Markers.

Deleting Markers

To delete a marker, see Deleting a Marker.

Snapping Markers on Circular Graphs

You can snap point markers and reference point markers on circular graphs based on the following point of interest (POI) criteria:

POI criteria defines the data point on the trace where the marker is moved when you snap it.

Follow these steps to snap a point marker or a reference point marker on a circular graph:

  1. Select the marker and choose either Frequency or Specific Frequency as the POI criteria from the POI criteria drop-down list displayed on the snap toolbar, as shown in the following figure.
    The text field displayed next to the POI criteria drop-down list appears dimmed, and becomes available only when you select Specific Frequency as the POI criteria.
  2. Depending upon the POI criteria that you selected in step 1, do the following:
    • If you selected Frequency, click Next POI or Previous POI on the snap toolbar to move the marker to the next or previous data points, respectively.
      You can also use the N or P bindkeys to snap the marker to the next or previous data points, respectively.
      • Clicking Next POI or pressing the N bindkey snaps the marker on the trace to a data point where the next higher frequency is available.
      • Clicking Previous POI or pressing the P bindkey snaps the marker on the trace to a data point where the next lower frequency is available.
        Next POI and Previous POI commands are disabled when you set the POI criteria to Specific Frequency.
    • If you select Specific Frequency, the text field next to the POI criteria drop-down list becomes available. Specify the frequency value in the field to snap the marker to that location.

You can also snap a marker by clicking the Next POI and Previous POI commands from the context menus of the Point Marker Properties and Smith Reference Point Marker Properties forms.

Alternatively, you can specify the frequency in the Frequency fields on these forms to snap the markers. See the Setting Point Marker Properties for a Circular Graph and Setting Smith Reference Point Marker Properties sections for more information.

Plotting Circular Graphs with Different Axis Units

By default, the circular graphs with the matching dependent axis units are plotted in the append mode in the same window.

To append data with different dependent axis units to an existing polar or smith graph,

Zooming Circular Graphs

You can zoom in or out the circular graph by doing the following:

When you zoom in a graph, the labels for the zoomed-in area are displayed outside the standard unit circle.

Editing Circular Graph Properties

To set the properties of the circular graph, do one of the following:

This form includes the following two tabs:

Filtering Data Using the Frequency Slider Bar

You can use the frequency slider bar as a frequency filter to set a range of frequencies. Data on the circular graph is filtered and selectively displayed based on the specified frequency range.

The frequency slider bar is hidden by default. To view the frequency slider bar, set the environment variable viva.circGraph showFreqFilterBar to true.

The following figure shows the frequency slider bar that appears on top of a circular graph.

The default frequency range of the slider bar varies depending on the simulation data.

To set the minimum and the maximum frequencies, do the following:

  1. Move the left end of the slider bar to set the minimum frequency.
  2. Move the right end of the slider bar to set the maximum frequency.
  3. Move the slider bar to the left or right of the graph to change both the minimum and the maximum frequencies simultaneously.
  4. Double-click the slider bar to open the Zoom To form, where you can set the values of Minimum and Maximum frequencies.

    You can also use suffix notation to specify the minimum and maximum frequency values. For example, KHz, MHz, and GHz.
  5. Right-click the slider bar and select one of the following options to reset the applied frequency filters:
    • Reset Frequency Limits: Resets the frequency filter to its default range.
    • Reset Minimum Frequency: Resets the minimum frequency limit to its default value.
    • Reset Maximum Frequency: Resets the maximum frequency limit to its default value.

Setting Smith Grid Properties

To set the Smith grid properties, right-click a Smith chart and choose Smith Grid Properties. The Smith Grid Properties form appears.

The form includes the following fields:

Setting Polar Grid Properties

To set the polar grid properties, right-click a polar plot and choose Polar Grid Properties. The Polar Grid Properties form appears.

This form includes the following fields:

Setting Dependent Modifiers for a Complex Trace

You can set the dependent modifiers for an AC or a complex dataset, such as Mag, dB10, dBm, and dB20. You can also calculate these modifiers based on the resulting eye diagram and the spectrum waveform.

To change the modifier for an AC or a complex dataset, do one of the following:

Setting Bindkeys

A bindkey is a key or a sequence of key press events linked (bound) to a task. When you press the key or the sequence of keys, the associated task is performed. The Virtuoso Visualization and Analysis XL too provides a set of default bindkeys, which are displayed next to the relevant commands on the menus. These bindkeys can be overwritten or modified by a customized bindkey file.

The sample bindkey files are found at the following locations:

$CDSHOME/tools/dfII/samples/local/vivaBindKeys.il

$CDSHOME/tools/dfII/samples/local/vivaJavaBindKeys.il

To view all the bindkeys for the Virtuoso Visualization and Analysis XL tool, in CIW, choose Options Bindkey. The Bindkey Editor appears that includes all the bindkeys for all applications, such as vivaBrowser, vivaCalculator, and vivaGraph.

You can map keystrokes to the tasks that you perform in the window. However, you cannot bind mouse actions to tasks. A task is defined as follows:

Task = { graph_task | menu_item_task | skill_function }

graph_task

Specifies the task that the bindkey is linked to. You can link a bindkey to any of the following tasks:
marker, vertmarker, horizmarker, deltamarker, vertcursor, horizcursor, deltacursor, tracecopywin, tracemovewin, tracecopysubwin, tracemovesubwin, logscale, cut, copy, paste, delete, cancel, undo, cancel, traceinfo, pandown, panup, panleft, panright, zoom, zoomx, zoomy, zoomin, and zoomfit

menu_item_task

Specifies the item name in the following format
graph.menu.submenu1.submenu2
For example, panning to the right is defined as follows: graph.zoom.pan.panright.

skill_function

Specifies the SKILL function call, such as awvFitMenuCB().
For information about SKILL functions, see the SKILL Language Reference.

A keystroke is defined as follows:

keystroke = simple_keystroke | composite_keystroke

simple_keystroke

A single letter, number, symbol, or key name.
Examples: a, 2, @, Up, F1

composite_keystroke

The format is modifiers<key>simple_keystroke
where modifiers = alt, ctrl, meta, shift, control, super, hyper, mod1, mod2, mod3, mod4, mod5
Examples: meta<key>Right, AltShift<key>F2

The below table lists the bindkeys available in Virtuoso Visualization and Analysis XL:

Command Bindkey

Results Browser

Open Results Browser using the Select Waveform form

Alt+F+O

Plot the selected signal(s) in the Results Browser

Ctrl+P

Reload the results in Browser

Ctrl+R

Create a table view of selected signals

Ctrl+T

Remove traces from the graph window

Ctrl+X

Calculator

Close Calculator

Ctrl+Q

Graph

Add an A type marker

A

Add a B type marker

B

Toggle the tracking cursor

C

Add a delta marker between two markers

Use Shift+D when two or more markers selected

Pan down

Down

Delete selected object

Delete

Delete All

E

Stop listening for signal selection in the Function Assistant

Escape

Zoom Fit

F

Toggle Assistants

F11

Toggle Toolbars

Ctrl+F11

Toggle Toolbars and Assistants

Shift+F11

Toggle Minor Grids

G

Toggle Major Grids

Shift+G

Toggle Minor and Major Grids

Add a horizontal marker

H

Pan left

Left arrow

Add a marker

M

Jump to next edge

N

Jump to previous edge

P

Edit attributes of the selected object

Q

Add a reference point marker

R

Pan right

Right arrow

Add a transient edge marker

T

Undo

U

Add a vertical marker

V

Zoom in X

X (RMB+drag), Shift+RMB+drag or Shift+ mouse scroll

Zoom in Y

Y (RMB+drag), Ctrl+RMB+drag, or Ctrl+ mouse scroll

Zoom in XY

Z (RMB+drag box) or RMB+drag box

Zoom Out

[

Zoom in

]

Select all traces in a strip

Ctrl+A

Select all traces

Ctrl+Shift+A

Redo

Shift+U

Paste

Ctrl+V

Save graph

Ctrl+S

Load graph

Ctrl+V

Fit Trace

Ctrl+F

Fir Smith

Shift+F

Edit graph properties

Shift+Q

Cut

Ctrl+X

Copy

Shift+C

Create new plot window

Ctrl+N

Close all windows

Ctrl+Q

Delete all traces

Shift+E

Delete all markers

Ctrl+E

Update/Reload Graphs

Ctrl+R

Working with Tabular Graph

You can use tabular graph to display waveform data in a table. Tabular graphs offer a convenient way to analyze waveform data, especially for S-Parameter data.

This section included the following topics:

You can watch a video demonstration for this feature. Also, read the related blog.

Creating a Tabular Graph

To create a tabular graph:

  1. From the File tool bar of Virtuoso Visualization and Analysis XL, choose Create New Window – Tabular.
    An empty tabular graph window opens.
  2. From the Results Browser, right-click the signals, and then select Plot Signal.
    Alternatively, you can drag the signals onto the tabular graph window.
    The waveform data of the selected signals is displayed in a table in the tabular graph window.
    The left-most column in the table represents the X-axis values. The multi-level headers represent the trace names and their Y-axis values for the corresponding X-axis values.
    The empty cells in the table indicate that the corresponding data points are not available in the trace. However, you can obtain these values using interpolation method by right-clicking any cell and then choosing Tabular Trace Properties – Interpolate. The interpolated values are updated in the tabular graphs. These values are marked with an asterisk (*).

The corner names and sweep parameters are displayed as headers in the tabular graph, as shown in the following figure.

Editing Tabular Graph Properties

To edit the properties of a tabular graph:

  1. From the menu bar of Virtuoso Visualization and Analysis XL, choose Graph – Properties.
    Alternatively, right-click on the tabular graph window, and then select Tabular Graph Properties.
    The Tabular Graph Properties form is displayed.
  2. On the General tab, specify the following properties:
    • Graph Title— Title of the graph that is displayed at the top of the graph. When you select the Default check box next to this field, you cannot edit the graph title or provide a new graph title. The default graph name includes the name of the analysis and the Y-axis name.
    • User Title— Title of the graph window that you want to set. You must clear the Default check box to edit this field.
    • Title Font— Font properties of the graph title.
  3. On the Graph Options tab, specify the following fields:
    • Interpolation— Interpolated values of the signal for data points that are not available in the trace are shown in the tabular graph. These values are marked with an asterisk (*).
    • Font— The font properties for the graph and its components, such as labels and axes.
    • Use Common Format— Common format of notation is used for all values in the tabular graph.
    • Notation—Specifies the notation type to be used for displaying data. You can specify one of the following three notation types:
      • Engineering— Displays data by using the engineering notation.
      • Suffix— Displays data by using the suffix notation.
      • Scientific— Displays data by using the scientific notation.
    • Significant Digits— Number of significant digits to be displayed in the calculated values. The default value is 4. You must select Manual to edit this value.
    • Reload using Current Context— When this check box is selected, signals in the graph are reloaded according to the data from the current in-context results directory. If this check box is not selected, signals are reloaded based on their individual databases. This check box is selected by default.
  4. Click Apply and then click OK to save the changes.

Using Tabular Trace Properties Commands for a Column

Right-click a column header in the tabular graph, and then select one of the following Tabular Trace Properties commands:

In addition to these commands, you can also use the following context-menu commands upon right-clicking a column header of a tabular graph:

Using Tabular Trace Properties Commands for a Row

Right-click a row in the tabular graph, and then select one of the following Tabular Trace Properties commands:

Customizing Display of S-Parameter Data

Tabular graphs offer a convenient way of analyzing S-Parameter data for different modifiers.

To customize display of S-Parameter data for different modifiers:

  1. Plot S-Parameter data in a tabular graph window. See the Creating a Tabular Graph section for more information.
    The following figure shows an example of S-Parameter data plotted as a tabular graph.
  2. Select a column header for which you want to customize the display.
  3. Right-click the selected column and then select Customize Display.
    The Complex Display form opens.
  4. From the Modifiers list, select the modifiers for which you want to display the values of S-Parameters. For example, Real and Imaginary, and then click OK.
    The S-Parameter values for the selected modifiers are displayed in the tabular graph.

Graph Summary Label

A graph summary label provides summarized information of graph measurements for histograms, direct measurements, and normal quantile plot (QQ plot) in an easy-to-view layout.

The following figure shows how various direct measurements for multiple signals are shown in a graph summary label.

The following figure shows how various graph measurements for multiple histograms are shown in a graph summary label.

The following figure shows how graph measurements p-value (p) and correlation coefficient (r) for normal quantile plot (QQ plot) are shown in a graph summary label.

The ellipsis (...) displayed at the bottom-left corner of a graph summary label indicates that there are more graph measurements to view. You can choose to view the summary of these measurements out of the graph window or subwindow in a separate Summary Information form.

You can watch a video demonstration for this feature at Graph Summary Label. Also, read the related blog at Virtuoso Video Diary: Usability of the Graph Summary Label in Virtuoso Visualization and Analysis XL Levels Up.

Related Topics

Hiding a Graph Summary Label

Viewing Graph Summary Information

Editing the Properties of a Graph Summary Label

Hiding a Graph Summary Label

You can hide the graph summary label if you want to focus only on the graph. To do this:

  1. Right-click anywhere on the graph summary label and choose Expand/Collapse.
    The graph summary label is collapsed and an icon is displayed.
  2. To bring the graph summary label back, right-click the ‘i’ icon and choose Expand/Collapse.

Related Topics

Graph Summary Label

Viewing Graph Summary Information

Editing the Properties of a Graph Summary Label

Viewing Graph Summary Information

To view the graph summary information:

  1. Right-click anywhere on a graph label and choose Summary Information.
    The Summary Information form opens, displaying the graph measurements for all the signals of the graph window or subwindow.
  2. Click Close to close the Summary Information form.

You can also copy the graph summary information to the clipboard. To do so, right-click the graph summary label and select Copy.

Related Topics

Graph Summary Label

Hiding a Graph Summary Label

Editing the Properties of a Graph Summary Label

Editing the Properties of a Graph Summary Label

To edit the properties of a graph summary label:

  1. Right-click anywhere on a graph label or on the icon and choose Summary Properties.
    The Summary Data Properties for Graph form opens.
  2. In the Font/Color field, click Default to open the Define Font form where you can select the font, font style, and font size. You can also choose to apply Strikeout or Underline effects on the selected font.
  3. Click OK to apply the changes and return to the Summary Data Properties for Graph form.
  4. Click Foreground to choose the font color for the graph summary label.
  5. Click OK to apply the settings.

Related Topics

Graph Summary Label

Hiding a Graph Summary Label

Viewing Graph Summary Information

Annotating Scalar Outputs for Single-Point Simulation

You can annotate scalar outputs in the graph window from the results of a single-point simulation. To annotate scalar outputs:

  1. Depending on whether you are using ADE Explorer or ADE Assembler, do one of the following:
    • From the menu bar of ADE Assembler, choose Options – Plotting/Printing.
      The ADE Assembler Plotting/Printing Options form opens.
    • From the menu bar of ADE Explorer, choose Results – Plotting/Printing Options.
      The ADE Explorer Plotting/Printing Options form opens.
  2. In the Graph Annotations group of the Plot section, select the Scalar Outputs for Single-Point Simulation check box.
  3. Click Run Simulation.
    Simulation results are displayed in the Results tab. When you plot simulation results in Virtuoso Visualization and Analysis XL, the outputs that returned scalar values are annotated in the graph window.

Consider the following test setup in ADE Assembler. The setup has two tests, AC and TRAN. Both the tests contain scalar outputs for which units are defined in the Units column.

Simulation results are displayed in the Results tab. The following figure shows that AC has five scalar outputs and TRAN has four scalar outputs.

The following figure shows scalar outputs of AC annotated in a summary label when you click Plot All to plot simulation results. The summary label displays the test name and scalar outputs with their corresponding units.

The following figure shows scalar outputs of TRAN annotated in a summary label when you click Plot All to plot simulation results. The summary label displays the test name and scalar outputs with their corresponding units.

Related Topics

Hiding the Summary Label for Scalar Outputs

Viewing Summary Information of Scalar Outputs

Editing Properties of the Summary Label

scalarOutputs

Hiding the Summary Label for Scalar Outputs

You can hide the summary label for scalar outputs if you want to focus only on the graph. To hide the summary label for scalar outputs:

  1. Right-click anywhere on the summary label and choose Expand/Collapse.
    The summary label is collapsed and an icon is displayed.
  2. Right-click the icon and choose Expand/Collapse to display the summary label again.

Related Topics

Annotating Scalar Outputs for Single-Point Simulation

Viewing Summary Information of Scalar Outputs

Editing Properties of the Summary Label

Viewing Summary Information of Scalar Outputs

You can view summarized information of scalar outputs in the Summary Information window, which can be placed side-by-side with the graph window.

To view summary information of scalar outputs out of the graph window:

  1. Right-click anywhere in the summary label and choose Summary Information.
    If the summary label is hidden, right-click the icon and choose Summary Information.
    The Summary Information window appears, displaying scalar outputs and their values.
  2. Click Close to close the window.

You can also copy the summary information to the clipboard. To do so, right-click the summary label and choose Copy.

Related Topics

Annotating Scalar Outputs for Single-Point Simulation

Hiding the Summary Label for Scalar Outputs

Editing Properties of the Summary Label

Editing Properties of the Summary Label

To edit properties of the summary label:

  1. Right-click anywhere in the summary label and choose Summary Properties.
    If the summary label is hidden, right-click the icon and choose Summary Properties.
    The Summary Data Properties for Graph form opens.
  2. In the Font/Color field, click Default to open the Define Font form where you can select the font, font style, and font size. You can also choose to apply Strikeout or Underline effects on the selected font.
  3. Click OK to apply the changes and return to the Summary Data Properties for Graph form.
  4. Click Foreground to choose the font color for the summary label.
  5. Click OK to apply the settings.

Related Topics

Annotating Scalar Outputs for Single-Point Simulation

Hiding the Summary Label for Scalar Outputs

Viewing Summary Information of Scalar Outputs

Graph Properties Form (Circular Graphs)

The Graph Properties Form for a circular graph lets you specify various graphs and grid properties. You can also use this form to annotate VSWR (Voltage Standing Wave Ratio) circles and Q contours.

The form contains the following tabs.

Tab Description
General Tab

Lets you specify graph properties of a circular graph.
Grid Tab

Lets you specify grid properties of a circular graph.
Annotations Tab

Lets you display VSWR circles and Q contours in a circular graph.
Markers Tab

Lets you display the tracking information for the points that you click or point to on a circular graph.

General Tab

The following table describes the fields that are available on the General tab of the Graph Properties form.

Field Description
Title

This section provides options to specify the title and font of a circular graph.

Graph Title

Displays the title of the circular graph at the top-left corner of the graph window or subwindow.

The default graph title includes the name of the analysis and the frequency range.

You must deselect the Default check box to edit the graph title.

Font

Specifies the font properties, such as style, size, and effects, for the graph title.

Graph

This section provides options to specify the properties of a circular graph.

Notation

Specifies the notation to be used in the graph labels. Possible values are:

  • Engineering: Uses engineering notation. For example, 29E6 Hz.
  • Scientific: Uses scientific notation. For example, 2.9E7 Hz.
  • Suffix: (Default) Uses suffix notation. For example, 29M Hz.

Legend Position

Specifies the position of the trace legend in the circular graph. Possible values are left, inside, and above. Default value is left.

Legend Font

Specifies the font properties, such as style, size, and effects, of the trace legend.

Reload Using Current Context

Specifies whether to reload signals in the graph according to the data from the current in-context results directory. This check box is selected by default. If this check box is not selected, signals are reloaded based on their individual databases.

Frequency Filter

This section provides options to filter graph data by frequency.

Enable

Specifies whether to enable the frequency filter. The frequency filter is disabled by default. If you select this check box, a frequency filter is displayed as a slider bar on top of the circular graph.

Min

Specifies the minimum frequency.

This field becomes available only when you select the Enable check box.

You can click the Reset command to reset the minimum frequency to its default value.

Max

Specifies the maximum frequency.

This field becomes available only when you select the Enable check box.

You can click the Reset command to reset the maximum frequency to its default value.

Grid Tab

The following table describes the fields that are available on the Grid tab of the Graph Properties form.

Field Description

Grid Type

Lets you select the type of grid for a circular graph:

  • Polar: Displays the polar grids.
  • Impedance: Displays the impedance Smith grid (Z Smith grid).
  • Admittance: Displays the admittance Smith grid (Y Smith grid).
  • Immittance: Displays the immittance Smith chart (ZY Smith grid).

Circles

This section provides options to specify how you want to draw circles on the polar grid.

This section is available only for polar grids.

Number of Circles

Specifies the number of circles you want to draw on the polar grid. The default value is 0, which indicates that the number of the circles displayed depends upon the plotted data.

Display Circle Grids

Specifies whether to display circular grids. This check box is selected by default.

Display Circle Grid Labels

Specifies whether to display labels for the circular grids. This check box is selected by default.

Display Unit Circle

Specifies whether to display a unit circle, which means a circle with radius 1.

This check box is selected by default.

Radials

This section provides options to specify how you want to draw radials on the polar grid.

This section is available only for polar grids.

Number of Radials

Specifies the number of radials you want to draw in each quarter of the polar grid. The default value is 2.

Display Radials

Specifies whether to display radials. This check box is selected by default.

Display Radial Labels

Specifies whether to display labels for the radials. This check box is selected by default.

Display

This section provides options to specify how you want to display circular grids.

This section is not available for polar grids.

Coefficient Ring

Specifies whether to display the angles of reflection coefficient in degrees.

Compressed Smith

Specifies whether to display extra horizontal grid lines (arcs) outside the Smith chart boundary.

Detailed Grid

Specifies when to display detailed grid lines. Possible values:

  • off: Detailed grid lines are always hidden.
  • on: Detailed grid lines are always displayed.
  • auto: Detailed grid lines are automatically displayed when zooming in on the Smith chart.

This option is not available if the Compressed Smith check box is selected.

Grid Labels

Specifies whether to display the grid labels. This check box is selected by default.

Labels

This section provides options to specify properties of grid labels.

This section is not available for polar grids.

Imag. Circles

Specifies whether to display labels on the imaginary circles.

Font

Specifies the font properties, such as size, style, and effects, of the grid labels.

Text Size

Specifies the text size for the grid labels. Possible values:

  • Auto: (Default) Automatically adjusts the text size for the grid labels.
  • Fixed: Uses a fixed text size for the grid labels.

Grid Lines

This section provides options to specify properties for the standard and detailed grid lines in the impedance, admittance, and immittance charts.

This section is not available for polar grids.

Standard

Lets you select the color, width, and style of the standard grid lines for the impedance, admittance, and immittance charts.

Detailed

Lets you select the color, width, and style of the detailed grid lines for the impedance, admittance, and immittance charts.

Annotations Tab

The following table describes the fields that are available on the Annotations tab of the Graph Properties form.

This tab is not applicable for polar grids.

Field Description
Smith Chart

This section provides options to display VSWR (Voltage Standing Wave Ratio) circles and Q contours on the Impedance, Admittance, and Immittance Smith charts.

VSWR Circles

This section lets you display VSWR circles for the specified VSWR values. You can also specify options to annotate VSWR circles.

VSWR

Specifies the VSWR value for which you want to draw the VSWR circle. Click the ‘+’ icon to specify the VSWR value. You can specify multiple VSWR values.

Color

Specifies the color of the VSWR circles. The default color is #c0c000 (La Rioja).

Width

Specifies the thickness of the VSWR circles. Possible values are: Fine, Medium, Thick, ExtraThick, and ExtraFine. The default value is Fine.

Style

Specifies the style of the VSWR circles. Possible values are: Solid, Dot, Dash, DashDot, and DashDotDot. The default value is Solid.

Q Contours

This section lets you display Q contours for the specified Q values. You can also specify options to annotate Q contours.

Q

Specifies the Q value for which you want to draw the Q contours. Click the ‘+’ icon to specify the Q value. You can specify multiple Q values.

Color

Specifies the color of the Q contours. The default color is ##c000c0(Deep Magenta).

Width

Specifies the thickness of the Q contours. Possible values are: Fine, Medium, Thick, ExtraThick, and ExtraFine. The default value is Fine.

Style

Specifies the style of the Q contours. Possible values are: Solid, Dot, Dash, DashDot, and DashDotDot. The default value is Solid.

Markers Tab

The following table describes the fields that are available on the Markers tab of the Graph Properties form.

Field Description
Labels

This section provides an option to specify the text format of the tracking marker.

Tracking Format (Trace)

Specifies the text format to be displayed in the label of a tracking marker. If you leave this field blank, the following default values are used depending upon the selected grid type:

  • Polar grid: %F%n%C
    Frequency and real and imaginary Cartesian values are displayed in the label text of a tracking marker. %n indicates that values are displayed in a new line.
  • Impedance (Z Smith) grid: %F%n%Z
    Frequency and impedance values, such as resistance and reactance are displayed in the label text of a tracking marker.
  • Admittance (Y Smith) grid: %F%n%A
    Frequency and admittance values, such as conductance and susceptance are displayed in the label text of a tracking marker.
  • Immittance (ZY Smith) grid: %F%n%Z%n%A
    Frequency, impedance, and admittance values are displayed in the label text of a tracking marker.

Impedance/Admittance Values

This section provides options to specify graph properties of a circular graph.

Normalize

Specifies whether to normalize the Smith reference values. When you select the Normalize check box, the Smith reference values are multiplied with the impedance value specified in the Characteristic Impedance field

Characteristic Impedance

Specifies the characteristic impedance value. The default value is 50 ohms.


Return to top
 ⠀
X