jitterDutyCycle

Measure jitter correlated with duty cycle distortion

Since R2024b

Syntax

[DCDrms,DCDpkpk] = jitterDutyCycle(x,y,SymbolTime = t)

[DCDrms,DCDpkpk] = jitterDutyCycle(y,SampleInterval = s,SymbolTime = t)

[DCDrms,DCDpkpk] = jitterDutyCycle(x,y,xr,yr)

[DCDrms,DCDpkpk] = jitterDutyCycle(y,yr,SampleInterval = s)

[DCDrms,DCDpkpk] = jitterDutyCycle(___,Name=Value)

[DCDrms,DCDpkpk,C] = jitterDutyCycle(___)

Description

[DCDrms,DCDpkpk] = jitterDutyCycle(x,y,SymbolTime = t) measures the duty cycle distortion (DCD) from input jittery waveform by using the specified symbol time.

For PAM2 waveform. DCD captures the component jitter in every other symbol. When generalized to PAMn, DCD can refer to either of these two:

• every other symbol to capture the effects of an underlying clock.

• rising vs. falling transitions to capture switching effects.

[DCDrms,DCDpkpk] = jitterDutyCycle(y,SampleInterval = s,SymbolTime = t) measures DCD by using the specific sample interval and symbol time.

[DCDrms,DCDpkpk] = jitterDutyCycle(x,y,xr,yr) measures DCD from input jittery waveform with respect to the reference waveform.

[DCDrms,DCDpkpk] = jitterDutyCycle(y,yr,SampleInterval = s) measures DCD with respect to the reference waveform and specified sample interval.

[DCDrms,DCDpkpk] = jitterDutyCycle(___,Name=Value) measures DCD using name-value arguments. Unspecified arguments take default values.

[DCDrms,DCDpkpk,C] = jitterDutyCycle(___) measures the rms and peak-to-peak DCD using the above arguments. It also estimates the correlation information for DCD.

Input Arguments

x — Time coordinates of jittery signal

vector

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

y — Amplitude coordinates of jittery signal

vector

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

xr — Time coordinates of reference signal

vector

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

Data Types: double

yr — Amplitude coordinates of reference signal

vector

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: J = jitterDutyCycle(x,y,SampleInterval = s,Plot = on) calculates and plots the histogram of DCD from the input waveform defined by (x,y) and sample interval specified by s.

SymbolThresholds — Thresholds to separate symbol levels in jittery waveform

vector

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

ReferenceThresholds — Thresholds to separate symbol levels in reference waveform

vector

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

SampleInterval — Sample time for uniformly sampled jittery and reference waveforms

scalar

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

SymbolTime — Symbol time for uniformly sampled jittery and reference waveforms

scalar

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

Match — Options to compare data edge to clock edge

time (default) | order

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.

Plot — Option to display histogram of duty cycle distortion

false or 0 (default) | true or 1

Option to display histogram of duty cycle distortion, specified as true (1) or false or (0).

Data Types: double

DCDMethod — Reference for correlating duty cycle distortion

oddeven (default) | risefall

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

Data Types: char

BinEdges — Bin edges for PDFs during correlation

vector

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

Output Arguments

DCDrms — RMS duty cycle distortion

scalar

Observed rms duty cycle distortion, returned as a scalar.

DCDpkpk — Peak-to-peak duty cycle distortion

scalar

Observed peak-to-peak duty cycle distortion, returned as a scalar.

C — Correlation information for DCD

structure

Correlation information for DCD, returned as a structure. The structure contains these fields.

Field	Description
Metric	Name of the metric.
Mean	Mean of each case, returned as a vector with two elements: [rise,fall] or odd.even.
Variance	Variance of each case, returned as a vector with two elements: [rise,fall] or odd.even.
PDF	PDFs for each case, returned as a vector with two elements: [rise,fall] or odd.even.
BinEdges	Bin edge vector for PDFs.
SymbolIndex	Maps the delays for mean and variance for each column to the corresponding symbol.

Version History

Introduced in R2024b