[FieldTrip] Fwd: Question about unit of the wavelet analysis

[jan-mathijs schoffelen]

Dear Theresa, 

I am forwarding your questions to the discussion list, as this is the forum on which we discuss this type of issues. Other people may benefit from it too, or may feel inclined to answer.

Cheers,

Jan-Mathijs

Begin forwarded message:

> From: Theresa Götz <theresa at biomag.uni-jena.de>
> Date: April 25, 2012 9:52:33 AM GMT+02:00
> To: j.schoffelen at donders.ru.nl
> Subject: Question about unit of the wavelet analysis
> 
> Dear Jan-Mathijs Schoeffelen,
> 
> we have a question about the unit of the time-frequency power spectrum:
> maybe you can help me with that.
> 
> 1. In fieldtrip, we performed ft_frequanalysis with method 'wavelet' and
> output 'power'. What is the exact unit of the resulting power spectrum
> (e.g. V/sqrt(hz) or V^2/Hz or V^2 or V)?
> 
> 2. Why does the amplitude of power spectrum decrease toward higher
> frequencies even though we keep the amplitude of the input sine wave (in
> time domain) constant?
> 
> Thank you very much.
> 
> Best,
> Theresa
> 
> 
> 
> 
> -- 
> Bitte denken Sie an die Umwelt, bevor Sie diese e-Mail ausdrucken.
> 
> 
> Dr. Theresa Götz		 Phone:	+49-3641-9325780
> University Hospital Jena         Fax:   +49-3641-9325772
> Dept. for Neurology
> Biomagnetic Center
> 
> Erlanger Allee 101
> D-07747 Jena
> Germany
> 
> 
> 
> 
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Jan-Mathijs Schoffelen, MD PhD 

Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands

Max Planck Institute for Psycholinguistics,
Nijmegen, The Netherlands

J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793

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