pulse2stateye

Statistical eye from pulse response

Syntax

[S,VH,TH] = pulse2stateye(P,N,M)

[___,S1] = pulse2stateye(P,N,M)

pulse2stateye(P,N,M)

[S,VH,TH] = pulse2stateye(P,N,M, ClockIndex)

Description

[S,VH,TH] = pulse2stateye(P,N,M) calculates and plots the statistical eye S from a pulse response P with N samples per symbol and M levels of modulation.

The statistical eye is generated by progressively accumulating the histogram of each vertical slice VH by perturbing the ideal cursor voltage by the inter-symbol interference (ISI) voltages defined by the pulse response.

The function uses Hula-Hoop algorithm.

[___,S1] = pulse2stateye(P,N,M) also returns the symbol transition histograms and crosstalk histogram S1.

pulse2stateye(P,N,M) calculates and plots the statistical eye to the current figure.

[S,VH,TH] = pulse2stateye(P,N,M, ClockIndex) centers the resulting eye diagram at the clock index instead of using the Hula-Hoop algorithm.

Examples

Plot Statistical Eye from Pulse Response

Load the pulse response column matrix from a file.

load('PulseResponseReflective100ps.mat');

Use the nonreturn to zero (NRZ) modulation scheme.

modulation = 2;

Calculate the statistical eye.

[stateye,vh,th] = pulse2stateye(pulse,SamplesPerSymbol,modulation);

Visualize the statistical eye using a color map.

cmap = serdes.utilities.SignalIntegrityColorMap;
figure,
imagesc(th*SymbolTime*1e12,vh,stateye)
colormap(cmap)
colorbar
axis('xy')
xlabel('ps')
ylabel('V')
title('Statistical Eye')

Input Arguments

P — Pulse response

column matrix

Input pulse response, specified as a column matrix. The first column contains the primary pulse response and the subsequent columns (if any) contain the crosstalk pulse responses.

Data Types: double

N — Number of samples per symbol

positive integer scalar

Number of samples per symbol, specified as a positive integer scalar.

Data Types: double

M — Number of modulation levels

positive integer scalar greater than or equal to 2

Number of modulation levels, specified as a positive integer scalar. M defines the modulation scheme used in the statistical eye calculation.

• If M = 2, the modulation scheme is nonreturn to zero (NRZ).

• If M = 4, the modulation scheme is four-level pulse amplitude modulation (PAM4).

Data Types: double

ClockIndex — Index of pulse response where clock is centered

scalar

Index of the pulse response where the clock is centered, specified as a scalar. When you specify the optional ClockIndex argument, the function centers the resulting eye diagram at the ClockIndex.

Data Types: double

Output Arguments

S — Statistical eye matrix

matrix

Statistical eye of the pulse response P, returned as a matrix.

Data Types: double

VH — Voltage histogram bin centers

vector

Vertical voltage histogram bin centers, returned as a vector.

Data Types: double

TH — Time histogram bin centers

vector

Horizontal time histogram bin centers, returned as a vector.

Data Types: double

S1 — Symbol transition histograms and crosstalk histogram

3-D matrix

Symbol transition histograms and crosstalk histogram, returned as a 3-D matrix.S1 is used to calculate the statistical eye S.

Data Types: double

Version History

Introduced in R2020a