How to decide the window, nfft and noverlap for mscohere function?

Hi all,

I am trying to use mscohere to calculate coherence for two time signals each 300 ms long with 1000 Hz sampling rate so total number of samples = 300. Could you please help me to figure out how to decide the Window, nfft and noverlap for using mscohere?

Thanks a lot!

[baba]

I am trying to calculate coherence for a band of frequencies, for ex. 8-15 Hz.

Answer 1

[André Lopes Brum]

d=4; % i got this 4 from a book, but i also saw some people using 8 instead

nfft=(nextpow2(length(x)/d))-1; nfft=2^nfft;

overlap = nttf/2;

window = hanning(nfft); % hanning is default

if you want to calculate the frequency of 15 Hz, you may need to rearrange your data, by setting:

F1= 15; % frequency that i wanna know

fs=F1/nfft;

and now interpolate your data with the new frequency sample, so the result of the mscohere.m will show you the frequency that you want to study.