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jitterRandom

Measure random jitter from waveform

Since R2024b

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Syntax

RJrms = jitterRandom(x,y,SymbolTime = t)
RJrms = jitterRandom(y,SampleInterval = s,SymbolTime = t)
RJrms = jitterRandom(x,y,xr,yr)
RJrms = jitterRandom(y,yr,SampleInterval = s)
RJrms = jitterRandom(___,Name=Value)
[RJrms,RJpdf,binEdges] = jitterRandom(___)

Description

RJrms = jitterRandom(x,y,SymbolTime = t) measures the random rms jitter from input jittery waveform by using the specified symbol time.

Random jitter accounts for any remaining jitter after accounting for the deterministic jitter. This jitter is unbounded.

RJrms = jitterRandom(y,SampleInterval = s,SymbolTime = t) measures the random rms jitter by using the specified sample interval and symbol time.

RJrms = jitterRandom(x,y,xr,yr) measures the random jitter from input jittery waveform with respect to the reference waveform.

RJrms = jitterRandom(y,yr,SampleInterval = s) measures the random jitter with respect to the reference waveform and specified sample interval.

RJrms = jitterRandom(___,Name=Value) measures the random jitter using name-value arguments. Unspecified arguments take default values.

[RJrms,RJpdf,binEdges] = jitterRandom(___) measures the random rms jitter using the above arguments. It also estimates the probability density functions (PDFs) and bin edges for the random jitter.

Input Arguments

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Time coordinates of the jittery signal, specified as a monotonically increasing vector.

If you do not provide y, the function interprets x as edge times.

Data Types: double

Amplitude coordinates of the jittery signal, specified as a vector or as an eyeDiagramSI object.

If you do not provide x, the function assumes y is uniformly sampled at the rate specified by SampleInterval.

Data Types: double

Time coordinates of the reference signal, specified as a monotonically increasing vector.

Data Types: double

Amplitude coordinates of the reference signal, specified as a vector. If you do not provide x, yr must be sampled at the same points as y.

Data Types: double

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: RJrms = jitterRandom(x,y,SampleInterval = s, Plot = on) calculates and plots the histogram of the random jitter from the input waveform defined by (x,y) and the specified sample interval.

General

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Thresholds to separate symbol levels in the jittery waveform, specified as a vector. If you do not provide SymbolThresholds, the function calculates it from the histogram of y.

Data Types: double

Thresholds to separate symbol levels in the reference waveform, specified as a vector. If you do not provide ReferenceThresholds, the function calculates it from the histogram of yr.

Data Types: double

Sample time for uniformly sampled jittery and reference waveforms, specified as a scalar.

When you provide the time vectors of jittery and reference signals, the function ignores SampleInterval and uses time vectors instead.

Data Types: double

Symbol time for uniformly sampled jittery and reference waveforms, specified as a scalar. For clock waveforms, SymbolTime is half the of the period.

Data Types: double

Options to compare the data edge to the clock edge, specified as one of these:

  • time — Compares the closest edge times.

  • order — Compares the first edge on each set.

The function uses this argument in two scenarios only:

  • Both the measured and reference waveforms are clocks.

  • The measured waveform is a data waveform and the reference waveform is a clock waveform.

When both waveforms are data waveforms with the same pattern, the function matches the edges is based on the pattern.

Option to display histogram of random jitter, specified as true (1) or false or (0).

Data Types: logical

Metric Specific

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Maximum number of sinusoidal jitter frequencies to measure, specified as a scalar.

Data Types: double

Number of symbols prior to a given edge to correlate the jitter with, specified as a scalar.

Data Types: double

Number of symbols after a given edge to correlate the jitter with, specified as a scalar. If the signal uses PAM2 modulation, the default value for FutureSymbols is 0. For a modulation scheme of PAM3 or higher, the default value is 1.

Data Types: double

Reference for correlating duty cycle distortion, specified as oddeven or risefall.

Data Types: char

Bin edges for PDFs during correlation, specified as a vector.

By default, the function distributes BinEdges evenly with twice the resolution of Scott's rule.

Note

For best results, specify a bin centered at 0.

Data Types: double

Premeasured Jitter

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Data-dependent jitter value for each edge, specified as a vector.

If you specify DDJ, the function ignores the specified DCD and ISI values while estimating deterministic jitter and random jitter.

Data Types: double

Timing error values due to inter-symbol interference (ISI), specified as a vector or a structure.

The structure contains the correlation information and is the output of the jitterIntersymbol function. The structure must contain these fields.

FieldDescription
Mean

[N×M] matrix, where N is the number of modulation levels and M is the sum of future symbols and past symbols.

Mean denotes the ISI values for each symbol level at each delay.

SymbolIndex

M long vector, where M is the sum of future symbols and past symbols. The vector cannot contain 0.

SymbolIndex specifies the delay each column of Mean corresponds to.

Delay is relative to the symbol edge at which the function applies the ISI. A delay of 1 corresponds to the symbol after the edge, and a delay of -1 corresponds to the symbol prior to the edge.

The elements of the vector denote the ISI values for each edge.

Timing error values due to duty cycle distortion (DCD), specified as a vector or a structure.

The elements of the vector denote the DCD values for each edge.

The structure contains the correlation information and is the output of the jitterDutyCycle function. The structure must contain the Mean field, which is a 2-by-1 matrix. The first element is the odd or rising DCD value and the second is the even or falling DCD value.

Data Types: double

Sinusoidal jitter, specified as an N-by-3 matrix. N is the number of sinusoidal jitter (SJ) peaks or frequencies.

Each row of SJ contains the amplitude, frequency, and phase values. Amplitude must be in the same unit as SampleInterval and SymbolTime. Frequency is in the inverse of the unit of amplitude. Phase is in radians.

Data Types: double

Output Arguments

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Observed rms random jitter, returned as a scalar.

PDF (probability distribution function) estimates of the random jitter, returned as a vector.

Bin edges for the PDFs for the random jitter, returned as a vector.

Version History

Introduced in R2024b

See Also

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