I have multiple, real, audio signals which I am taking the FFTs. Although they don't come from the same recording, those signals represent the same thing (biologically). I was told that I could combine those ffts and average them together to get a good representation of the averaged signal. I am thinking of using the matlab function 'pwelch' for this purpose but I have lots of questions and I could not find answers by googling.
I have already averaged the ffts themselves with the matlab function 'pwelch' to decrease the noise. When combining them together, should I just use the output of a normal FFT rather than the output of pwelch (P)?
My signals are not exactly of the same length, which will make them not usable to combine in a matrix. Should I cut them all to the same length before averaging? Or is there a way round that?
How do I actually combine them? I was thinking something like this:
avg = (abs(P1) + abs(P2) + abs(P3)) / 3;
and then use the function pwelch like this:
[Pavg, Favg] = welch(avg,ones(SegmentLength,1),0,NFFTavg,fs,'power');
Any insights or help would be really appreciated. Thank you!