[Eeglablist] FFT in EEG signal
arno delorme
arno at ucsd.edu
Fri Sep 5 14:51:31 PDT 2008
Dear Starz,
If X is the data, nfft the size of the FFT window and srate the
sampling rate. The formula below will do all channels at once if they
are in the first dimension.
tmp = fft(X, nfft, 2);
f = linspace(0, srate/2, size(tmp,2)/2);
f = f(2:end); % remove DC (match the output of PSD)
tmp = tmp(:,2:size(tmp,2)/2,:); % the FFT decomposition is
symmetrical
res = 10*log10(mean(abs(tmp).^2,3));
figure; plot(f, res);
best,
Arno
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