Product Documentation
Spectre Circuit Simulator RF Analysis Theory
Product Version 23.1, June 2023

Contents

Preface

Using License Queuing
Suspending and Resuming Licenses

Related Documents for Spectre

Third Party Tools

Typographic and Syntax Conventions

1

Basic Reference Information

Periodic Analyses

Quasi-Periodic Analyses

Envelope Analysis

The Simulation Engines

Harmonic Balance (HB) Engine
Time Domain (TD) Engine

Periodic Steady-State Analysis

The Shooting Method
Distributed Components and Hidden State in PSS Analysis
Fundamental Assumptions for PSS Analysis

Periodic Small-Signal Analyses

Fundamental Assumptions for the Periodic Small-Signal Analyses

Quasi-Periodic Steady-State Analysis

Quasi-Periodic Noise Analysis

Envelope Analysis

The Harmonic Balance Engine

HB Method Theory
HB Convergence Criteria
HB Large Signal Simulation for Driven Circuits
The ADE Use Model
HB Large Signal Simulation for Autonomous Circuits
The ADE Use Model
HB Small Signal Setup
HB Envelope Analysis
The ADE Use Model
Multi-Thread Acceleration for Harmonic Balance Analysis
Distributed Component Support
Hidden State Issue
Frequently Asked Questions and Answers

Perturbation Based Measurements

Specialized PAC and AC Analyses for Measuring Distortion
About the IM2 Intermodulation Distortion Summary
About the Compression Distortion Summary
About the Perturbation Method
Frequently Asked Questions and Answers
References

Large Signal S-Parameters

Large-Signal S-Parameters for a Two-Port Circuit
References

Using the PSTB and STB Analyses with Linear Periodic Time-Varying Circuits

A Linear Periodic Time-Varying (LPTV) Feedback Circuit
Evaluating the Stability of a LPTV Circuit Using PSTB Analysis
Example 1: Comparing the STB and PSTB Analyses
Example 2: Local Stability of an Injection-Locked Oscillator
Example 3: Global Stability of Injection-Locked Oscillators

References

The Spectre/RF MATLAB Toolbox

Install the Toolbox Package
Configure the Toolbox Package
The Basic Toolbox Functions
The Measurement Commands
Example
Compatibility with Aptivia MATLAB Functions
Reference
MATLAB Support Matrix

Noise Separation in Pnoise and Qpnoise Analysis

Principles of Noise Separation in RF Circuits
The Noise Separation GUI
The Noise Separation Flow
Noise Separation Example

Simulating Noise and Jitter

Analyzing Time-varying Noise
Characterizing Time-Domain Noise
Calculating Time Domain Noise
Calculating Noise Correlation Coefficients
Cyclostationary Noise Example
Reference Information on Time-Varying Noise
Summary
Oscillator Noise Analysis
Phase Noise Primer
Models for Phase Noise
Calculating Phase Noise
Troubleshooting Phase Noise Calculations
Frequently Asked Questions
Further Reading
References
Measuring AM, PM and FM Conversion
Derivation
Simulation
Results
Conclusion
References

2

The Spectre RF Analyses

Periodic Steady-State Analysis (PSS)

The Shooting Method
Parameters for PSS Analysis
The PSS Algorithm for Driven and Autonomous Circuits
Driven PSS Analysis
Autonomous PSS Analysis
Simulation Accuracy Parameters
Plotting the Current Spectrum
The High-Order and Finite Difference Refinement Parameters
The errpreset Parameter in PSS Analysis
Other Parameters

Periodic AC Analysis (PAC)

Frequency Sweep
Modulated Small-Signal Analyses
Sampled Small-Signal Analysis
Parameters for PAC Analysis

Periodic S-Parameter Analysis (PSP)

Parameters for PSP Analysis

Periodic Transfer Function Analysis (PXF)

Parameters for PXF Analysis
Output Parameters
Probe Parameters
Output Parameters
Modulation Parameters
Sampled Small-Signal Analysis
Swept PXF Analysis

Periodic Noise Analysis (Pnoise)

Parameters for Pnoise Analysis

Periodic Stability Analysis (PSTB)

Parameters for PSTB Analysis
Sweep
Understanding Loop-Based and Device-Based Algorithms

Quasi-Periodic Steady-State Analysis (QPSS)

Comparing QPSS Analysis with PSS and PAC Analyses
QPSS Parameters
The errpreset Parameter in QPSS Analysis

Quasi-Periodic Noise Analysis (QPnoise)

QPnoise Output
QPnoise Parameters

Quasi-Periodic AC Analysis (QPAC)

QPAC Output Frequency and Sideband Vectors
QPAC Parameters

Quasi-Periodic S-Parameter Analysis (QPSP)

QPSP Output Frequencies and Sideband Vectors
Input and Output Frequencies in QPSP
Noise Analysis with QPSP
Swept QPSP Analysis
QPSP Parameters

Quasi-Periodic Transfer Function Analysis (QPXF)

QPXF Output Frequencies and Sideband Vectors
Transfer Function Inputs
Swept QPXF Analysis
QPXF Parameters

Harmonic Balance Steady State Analysis (HB)

Using Multi-rate Harmonic Balance to Improve Performance
HB Synopsis
HB Parameters
Details about Using HB Analysis Parameters

Harmonic Balance AC Analysis (HBAC)

HBAC Synopsis
HBAC Parameters
Details about Using HBAC Analysis Parameters

Harmonic Balance Noise Analysis (HBnoise)

HBnoise Synopsis
HBnoise Parameters
Details about Using HBnoise Analysis Parameters

HB S-Parameter Analysis (hbsp)

HBSP Parameters

Envelope Analysis (ENVLP)

A Mixer Example
The Time Domain and Harmonic Balance ENVLP Algorithms
Using ENVLP Analysis
AGC Example
ACPR Calculation
Autonomous ENVLP Analysis
Simulating Circuits with Driven FM Sources
Frequently Asked Questions
For what kind of circuits is multi-carrier HB Envelope suited?
Does multi-carrier HB Envelope support the function FM speed up?
Does multi-carrier HB Envelope handle autonomous circuits?
References

3

Oscillators and Autonomous PSS Analysis

Phases of Autonomous PSS Analysis

Starting the Oscillator

Convergence Issues with Autonomous PSS Analysis

Phase Noise in Oscillators

Sample Spectre RF Circuits

Characterizing a High-Performance Receiver
Characterizing a Switched-Capacitor Filter

References

4

Semi-Autonomous Simulation and Small Signal Analysis

Oscillator-Mixer co-simulation
Driven oscillator simulation

Initialization

tstab initialization method
Linear initial condition aided tstab

Newton Methods

Use Model

PSS simulation for semi-autonomous circuits
Small signal analysis for semi-autonomous circuits

Semi-Autonomous Simulation GUI

Trouble Shooting


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