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From: Stefanie on 11 Feb 2010 05:05
Hey there,

I'm trying to compute a spectrogram on my EEG Data. Therefore I'm using the Chronux Toolbox and the function mtdspecgramc which computes a spectrogram based on a multitaper analysis. I can get it to work but I'm confused about the resulting spectrogram. It always only shows power changes for the frequency band set in the taper parameter. For example if I set the tapers to a time-bandwith product (Time in s*Width in Hz) to 10 and the No of sequences (maximal 2*TW-1) to 19, the spectrogram shows power changes for frequencies up to 19 Hz. If I set the taper parameters to [50 99], I see the same power spectrum smeered to 100 Hz. I don't know what I'm doing wrong or maybe I just misunderstood the use of tapers. I'll appreciate any help on this!

Thanks,
Stefanie
From: Wayne King on 11 Feb 2010 06:39
"Stefanie " <steffi_rulla(a)hotmail.com> wrote in message <hl0koh$gue$1(a)fred.mathworks.com>...
> Hey there,
>
> I'm trying to compute a spectrogram on my EEG Data. Therefore I'm using the Chronux Toolbox and the function mtdspecgramc which computes a spectrogram based on a multitaper analysis. I can get it to work but I'm confused about the resulting spectrogram. It always only shows power changes for the frequency band set in the taper parameter. For example if I set the tapers to a time-bandwith product (Time in s*Width in Hz) to 10 and the No of sequences (maximal 2*TW-1) to 19, the spectrogram shows power changes for frequencies up to 19 Hz. If I set the taper parameters to [50 99], I see the same power spectrum smeered to 100 Hz. I don't know what I'm doing wrong or maybe I just misunderstood the use of tapers. I'll appreciate any help on this!
>
> Thanks,
> Stefanie

Hi Stefanie, you appear to have posted this question 3 times. I answered one of those posts.
Wayne
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