[Eeglablist] pop_spectopo jagged spectrum

Andreas Widmann widmann at uni-leipzig.de
Fri Aug 28 00:28:36 PDT 2015

Hi Max,

pwelch is quite sensitive to stronger DC offsets. I have seen similar patterns before. Do you possibly analyze raw Biosemi data? Could you please try to highpass filter the data?


> Am 27.08.2015 um 12:22 schrieb Maximilien Chaumon <maximilien.chaumon at gmail.com>:
> Hi,
> Running a spectopo command on a continuous dataset as follows:
> spec = pop_spectopo(EEG,1,[],'EEG','noplot','on','percent',5);
> I get a terrible jagged spectrum, really ugly like a saw.
> I tried to get to the bottom of the problem and ended up looking at the point where this pwelch function from signal toolbox is called. The spectrum that comes out of it is messed up (similar to above).
> So I made sure this pwelch function isn't used and it shows a much nicer (normal) power spectrum.
> Anyone had this issue already? How did you solve it?
> I filed a bug: Bug 1791
> Max
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