Generate a random sequence of PAM-4 but with values -1,-0.33,0.33,1

How to create a random PAM-4 signal with amplitude values of -1, -.033, 0.33, 1?

Answer 1

[the cyclist]

I didn't research PAM-4 enough to know whether each element is independent from prior values. The following code will generate a sequence of a specified length, randomly (and independently) selecting each element from the list of amplitudes. Maybe that is what you need, or you can adapt the idea.

% Set a random number generator seed
rng(2)

% Set the signal length and amplitude list
signalLength = 7;
amplitudeValues = [1, -.033, 0.33, 1];

% Generate a random index into the amplitude list
idx = randi(numel(amplitudeValues),signalLength,1);

% Get the amplitudes
signal = amplitudeValues(idx)

signal = 1×7

-0.0330 1.0000 0.3300 -0.0330 -0.0330 -0.0330 1.0000

If you have the Statistics and Machine Learning Toolbox, you could use randsample to simplify the syntax:

signalLength = 7;
amplitudeValues = [1, -.033, 0.33, 1];
signal = randsample(amplitudeValues,signalLength,true)

signal = 1×7

0.3300 -0.0330 -0.0330 0.3300 0.3300 1.0000 0.3300

[Aastha Singla]

Thank you!