[Eeglablist] Darbeliai plugin FFT doubt

Satya G PSYCHOLOGY satya.g at christuniversity.in
Tue Dec 3 03:21:13 PST 2019


Dear all,

I sometimes use the darbeliai plugin to calculate absolute and relative
power values for different frequency bands for a group of files. I have
resting EEG data sampled at 250 Hz, cleaned for artefacts and epoched at 2
second intervals.

I use the following settings:

*FFT window length (s): 1.996 *
*Spectrum steps in 1 Hz: 10*

However when I execute the operation in the command line i see this:
*Computing spectra (window length 499; fft length: 2500; overlap 0):*

The window length and fft length are different from what I expected.The
overlap is set to zero. I can't seem to find an option on the gui to change
it to 50%. And is fft is being calculated at every 499ms window with no
overlap?

I am not understanding what's happening to the data. I can change the
parameters in spectopo function directly in the command line but I would
like to process multiple files which is what Darbeliai plugin helps me
with. Does anyone have experience with this plugin who can help me
understand or perhaps the contributor of this plugin?

Thank You!

Sincerely,
Satya


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