[FieldTrip] Time-frequency analysis

[Kenji Kirihara]

Dear Jan-Mathijs,

Thank you for your advice.

Sincerely,

Kenji,


In message <5FE3FAAE-6A78-4033-B84C-AEB55E844285 at donders.ru.nl> fieldtrip at donder
s.ru.nl (jan-mathijs schoffelen) wrote:

> From: jan-mathijs schoffelen <jan.schoffelen at donders.ru.nl>
> Date: Tue, 16 Aug 2011 10:01:28 +0200
> To: Email discussion list for the FieldTrip project <fieldtrip at donders.ru.nl>
> Subject: Re: [FieldTrip] Time-frequency analysis
> 
> Dear Kenji,
> 
> In addition of applying the fft on the data, fieldtrip normalises the fft with
 a number that equals 2/Nsmp, where Nsmp is the length of the wavelet.
> 
> Best wishes,
> 
> Jan-Mathijs
> 
>  
> On Aug 15, 2011, at 11:00 PM, Kenji Kirihara wrote:
> 
> > Dear FieldTrip mailing list members,
> > 
> > I am interested in time-frequency analysis of EEG and have 
> > a question about ft_freqanalysis. I applied ft_freqanalysis to 
> > my data for time-frequency analysis using wavelets. Power at each 
> > time-requency point is calculated. However, power at each point 
> > seems to be too large. For example, power at 4 Hz, 0 ms, O2 is 1218, 
> > power at 10 Hz is 730, and power at 20 Hz is 94. These values seem 
> > to be too large compared to power calculated using FFT for frequency 
> > analysis. I would be grateful if someone tells me why this happens.
> > 
> > Sincerely,
> > 
> > Kenji Kirihara
> > _______________________________________________
> > fieldtrip mailing list
> > fieldtrip at donders.ru.nl
> > http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
> 
> Dr. J.M. (Jan-Mathijs) Schoffelen 
> Donders Institute for Brain, Cognition and Behaviour, 
> Centre for Cognitive Neuroimaging,
> Radboud University Nijmegen, The Netherlands
> J.Schoffelen at donders.ru.nl
> Telephone: +31-24-3614793
> 
> 
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