gaussian white noise with zero mean and 20 db power

Question

回答： Meg Noah 2025-8-6

how to generate gaussian white noise with zero mean and 20 dB power in Matlab

Answer 1

Meg Noah 2025-8-6

You also need to define the signal power level to get the order of magnitude.

signalPower = 2; % calculate the signal power from your signal data

nSamples = 1000;

snrDb = 20;

stdNoise = sqrt(signalPower / 10^(snrDb/10));

% generate the gaussian white noise

noiseMean = 0;

noiseValues = stdNoise*randn(nSamples,1) + noiseMean;

% verify the Signal-to-Noise value

noise_power_100_samples = sum(noiseValues.^2)/numel(noiseValues);

SNR = 10*log10(signalPower/noise_power_100_samples);

fprintf(1,"SNR: %f\n", SNR)

SNR: 19.727660

figure()

plot(1:nSamples,noiseValues);

ylabel('20dB Gaussian White Noise')

xlabel('Sample Index')