[Eeglablist] calculation of spectral Power

[Makoto Miyakoshi]

Dear Matthew and Arno,

At least for spectopo.m, there are parameters like nfft and winsize
that changes results a lot. I want to know what values you used for
the comparison test.

Makoto

2012/10/17 Don Scott <dscott8201 at gmail.com>:
> Hello,
>
> I have a question about how channel spectra are calculated.  The Plot menu
> calls pop_prop() which, in turn, appears to call (line 215) Spoectopo.m for
> the actual calculations using Welch's method (line 277) .  Then in line 306+
> the calculations occur, maybe rescaled by some kind of RMS value?   the plot
> eventually displayed shows the ordinate label as "Power 10*log10(uv^2/Hz)"
>
> I have tried to duplicate the EEGLAB results using the Matlab Signal
> Processing toolbox but cannot get the same numbers given by EEGLAB.
> Rescaling the sptool results by 10*log10(uv^2)/Hz) does not seem to help
> either.
>
> Can someone please help me clear this up, or point out what I am missing?  I
> need to know which is the correct set of data.
>
> Thank you
> Don
>
>
> --
> Don Scott
>
> (864) 415 - 1795
> Dscott8201 at Gmail.Com
>
> "Although the universe doesn't have an end, it had a beginning in the Big
> Bang. One might ask what is before that, but the answer is that there is
> nowhere before the Big Bang, just as there is nowhere south of the South
> Pole."
>
> --- Stephen Hawking
>
>
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-- 
Makoto Miyakoshi
JSPS Postdoctral Fellow for Research Abroad
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego