valueAt

valueAt(
o_waveform
n_xValue
[ ?extrapolate g_extrapolate ]
)
=> n_yValue / nil

Description

Returns the y-axis value of a waveform at the specified x-axis value.

Arguments

o_waveform	Waveform ID.
n_xValue	X-axis value at which the y-axis value is to be returned for the specified waveform.
?extrapolate g_extrapolate
	Specifies whether to use extrapolation to calculate the estimated y-axis value if the specified x-axis value does not exist. Valid values are: t: Extrapolation is used. nil: Extrapolation is not used.

Value Returned

n_yValue	Y-axis value of the waveform at the specified x-axis value.
nil	Y-axis value cannot be returned because of an error.

Examples

The following example returns the waveform ID of the eye diagram eye created from the jitter signal.

eye=eyeDiagram(v("jitter" ?result "tran-tran" ?resultsDir "/servers/user/design/prbs.raw") 200n 400u 2*40n   ?autoCenter t )

=> srrWave:0x336321f0

The following example returns the waveform ID of the curve representing the left-side bit error rate (BER) curve for the eye diagram eye.

waveform=eyeBERLeft(eye 200n 400u 80n 0.5 100)

=> srrWave:0x336322e0

The following example returns the last value at which the waveform returned by the function eyeBERLeft ends on x axis.

lastVal(waveform)

=> 2.353111e-08

Indicates that the waveform ends at x=23.53111ns.

The following example returns the y-axis value of waveform at x=23.5ns.

valueAt(waveform 23.5ns)

=> 5.096838e-07

The following example returns nil because the specified x-axis value 24.5ns is greater than 23.53111ns, which is the last value of waveform on x axis.

valueAt(waveform 24.5ns)

*Warning* : Index value out of range for waveform(nil)

=> nil

To return the y-axis value of waveform at x=24.5ns, set the ?extrapolate argument to t.

valueAt(waveform 24.5ns ?extrapolate t)

=> 9.066262e-08

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