# gaussian noise in infinite samples in real time matlab

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Rashi Mehrotra on 23 Jul 2021
Edited: Chunru on 26 Jul 2021
I am running a real time experiment which is always running and will stop if a user will send stop command.
The gaussian noise has to be added for infinite samples till the time user is not stopping the simulation.
How can I add gaussian noise for infinit samples.
Rashi Mehrotra on 26 Jul 2021
Th real question is I have to add gaussian noise for every sample of data which is received by the radar unit. This will add gaussian noise for infinite sample and stop whenever the radar stop sending. I hope it is clear now. Should I take the value of N as 2^19937 - 1 or for the infinite samples some other function has o be made.

Chunru on 26 Jul 2021
Edited: Chunru on 26 Jul 2021
t = 0;
sigma = 1; % noise rms value
while true
x = cos(2*pi*0.01*t); % received data
x = x + sigma * randn; % add noise
t = t + 1;
end
This way, you will keep adding noise to your received data indefinitely. The random number generator in matlab may repeat after some numbers ( 2^19937 - 1 ). This will be a huge number. If you using a sampling freuency of 1MHz, it may take this number of years :
vpa(sym(2)^19937/(1e6*365.25*24*3600))
ans =
1.367475599344741884064452149827e+5988
This wil take 10^5988 years (can you imagine how big this number is?) to repeat the random number. So you don't have to worry when the random number will repeat.
Anyway, even if it repeats, it unlikely has any side effect to your simulation.