[Eeglablist] Problem with pwelch in pop_spectopo function

[Makoto Miyakoshi]

Dear Agustin,

Hmm my guess is that data is much longer than we usually assume, so some
parameter that depends on the data length does not work. I recommend you
manually set the window length so that it is equivalent to be 1 second (it
depends on your sampling rate, EEG.srate).

I made a convenience wiki page. It has sample code to compute FFT for each
frequency band.
https://sccn.ucsd.edu/wiki/Makoto%27s_useful_EEGLAB_code

Makoto

On Thu, Dec 1, 2016 at 10:17 AM, Agustín Solano <
asolano at bioingenieria.edu.ar> wrote:

> Hello everybody,
>
> I am trying to plot Channel spectra and maps, using pop_spectopom. I use
> the default parameters set when the window opens but I get an error:
> "pwelch: arg 2 (window) must be integer > 3. Error ocurred in function
> pwelch() al line 493"
>
> In matlab commands windows I see:
>        Pop_spectopo: finding data discontinuities
>        Selecting the first 15.0% of data for analysis...
>        Computing spectra (window length 2.560164e+02; fft length:
> 2.560164e+02; overlap 0):
>
> My data is a continuous and long (sleep) dataset that was loaded from a
> .edf file, sampled at 256 Hz. I wonder if it is ok that window lenght is
>  2.560164e+02 by default?
> Any suggestions?
>
> Thanks,
>
> Agustín Solano
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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