# Frequency response of a long signal

I am trying to get the frequency response of a system, so, in theory I would need to do:

H = fft(y)./fft(x);


I have measured the system with a long stepped sine log sweep four times as I am planning to perform a spectral averaging to improve my SNR. This gives me a total of almost 5.000.000 samples per file. I have calculated the STFT of smaller chunks and averaged them as it looked like a too long signal to do an FFT. I used the cross spectrum and auto spectrum for that (I did the same procedure 4 times, one per audio file/repetition). However I think that's not the correct way to go as I am averaging a non stationary signal. Should I just do an FFT of the whole signal? Isn't it too long? Do you have any idea of how I should proceed?

• I'm sorry but I don't understand. If I used 500 frequencies and I do frame-by-frame deconvolution, then I would have 500 frequency responses. That is, if "f" is my 10k samples frame number, then I could do H(f) = Y(f)/X(f) My final goal is to obtain the overall frequency response of the system (in the frequency range that I applied). How do I combine each block to have an overall frequency response of the system? I saw that some people apply a weighted average, but not sure what the weights would be... – Emma1621 Apr 30 at 10:44