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noiseHistogram

Noise histogram

Description

example

nh = noiseHistogram(ed) returns the bin counts for the signal values at the vertical opening (eye delay) as set in eye diagram System object™.

Note

This method is available when both of these conditions apply:

  • EnableMeasurements is true

  • DisplayMode is '2D color histogram'

Examples

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Display the eye diagram for a waveform having dual-dirac and random jitter. Plot the jitter and noise histograms.

Specify the sample rate, the samples per symbol, and the number of traces parameters.

fs = 1000;
sps = 200;
numTraces = 1000;

Create an eye diagram object.

ed = comm.EyeDiagram('SampleRate',fs,'SamplesPerSymbol',sps, ...
    'SampleOffset',sps/2, ...
    'DisplayMode','2D color histogram','ColorScale','Logarithmic', ...
    'EnableMeasurements',true,'YLimits',[-1.2 1.2]);

Generate a waveform having dual-dirac and random jitter. Specify 3 ms rise and fall times.

src = commsrc.pattern('SamplesPerSymbol',sps, ...
    'RiseTime',3e-3,'FallTime', 3e-3);
src.Jitter = commsrc.combinedjitter('RandomJitter','on', ...
    'DiracJitter','on','DiracDelta',[-10e-04 10e-04],'RandomStd',5e-4);

Generate two symbols for each trace.

x = src.generate(numTraces*2);

Pass the signal through an AWGN channel with a fixed seed for repeatable results.

randStream = RandStream('mt19937ar','Seed',5489);
y = awgn(x,30,'measured',randStream);
ed(y)

Eye diagram

Calculate the jitter histogram count for each bin by using the jitterHistogram method. Plot the histogram.

jbins = jitterHistogram(ed);
plot(jbins)

Jitter histogram

Calculate the noise histogram count for each bin by using the noiseHistogram method. Plot the histogram.

nbins = noiseHistogram(ed);
plot(nbins)

Noise histogram

Input Arguments

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Eye Diagram System object, where the counts for signal values at the eye delay is set.

Output Arguments

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Noise histogram, which represent the counts for the signal values at the vertical opening (eye delay), specified as a nonnegative integer.

Data Types: double

Introduced in R2016b