how to determine the SNR using Matlab function in simulink ?

i want to generate the Matlab Function code in simulink that :

1-conver the signal from time domain to frequency domain by using fft

2- plot the frequency domian in dB

3- calculate the SNR of the signal

Answer 1

[Kanishk]

Hi Anas,

I understand you want to convert a signal from time domain to frequency domain. You can use MATLAB’s ‘fft’ function.

You can go through this official MATLAB documentation to transform a signal between time and frequency domain.

https://www.mathworks.com/help/releases/R2024a/ident/ug/transforming-between-time-and-frequency-domain.html

To plot the frequency domain in decibels, you can use this formula to convert the signal into decibels.

Y = fft(X, N);
Y = abs(Y(1:N/2+1));
fftResult_dB = 20 * log10(Y);

Here is a MATALAB answer on how to transform the data to decibels and plot it.

https://www.mathworks.com/matlabcentral/answers/1988038-fft-how-to-transform-my-amplitudes-into-db

To calculate the signal to noise ratio of the signal you can use MATLAB’s “snr” function. After creating a function, you can add it to Simulink using “MATLAB function block” as both “fft” and “snr” functions are supported by the block.

Please refer to the official MATLAB documentation of the “snr” function and “MATLAB function” block to learn more about them.

• https://www.mathworks.com/help/releases/R2024a/signal/ref/snr.html
• https://www.mathworks.com/help/releases/R2024a/simulink/ug/what-is-a-matlab-function-block.html

Hope this helps!!

Thanks