[Eeglablist] Default parameters used in calculating power values

[montaltomarco at onvol.net]

Dear List,

I am writing to ask for a little clarification. My data is sampled at a
rate of 512 Hz and my epochs are of 2-second duration (therefore each
epoch has 1024 points). I am designing a STUDY and when precomputing
channel measures I am choosing Power Spectrum with spectopo parameters:
'specmode', 'fft'.

I am then extracting power values using this bit of code supplied by
Arnaud (the example is with channel Fpz):

[ STUDY specdata specfreqs] = std_specplot(STUDY, ALLEEG, 'channels', {
'Fpz' });

I have checked specfreqs and the maximum frequency is (correctly) 256 Hz
and the frequencies are in approximately 0.5Hz steps (therefore my bin
resolution is approximately 0.5Hz).

Now if I am understanding everything correctly, my fft length should be
1024 seeing that the bin resolution is 0.5Hz and my sampling rate is 512
Hz (bin resolution = Fs / N, where Fs is the sampling rate and N is the
number of FFT points used; 512 / 1024 = 0.5Hz). Am I correct in assuming
this?

And what are the other default parameters used to calculate the power
values, such as window type, window size and overlap (if any)?

Looking forward to your replies!

Regards,
Marco