[Eeglablist] Wavelet type

[Arnaud Delorme]

Dear Elena,

as stated in the EEGLAB paper (*EEGLAB reference article in press, 
/Journal of Neuroscience Methods/* 
<http://www.sccn.ucsd.edu/eeglab/download/eeglab_jnm03.pdf> (.pdf, 0.6 
MB)), the timef() and crossf() function of EEGLAB for spectral 
decomposition use complex sinosoidal wavelets. Sinosoidal wavelet are 
just cosine (real part) and sine (imaginary part) tapered by a hanning 
function. Morlet wavelets involves a more complex tapering process. I 
have tested that the type of wavelet we use is virtually equivalent to a 
Morlet wavelet with specific parmeters (decay 0.7 and frequency scaling 
= 2pi). Only the normalization differs (but it does not alter the 
timef() and crossf() function results). In future versions of EEGLAB, we 
might allow users to use arbitrary Morlet wavelets.

Best

Arno

-- 

*Arnaud Delorme, Ph.D.*
Computational Neurobiology Lab, Salk Institute
10010 North Torrey Pines Road
La Jolla, CA 92037 USA

*Tel* : /(+1)-858-458-1927 ext 15/
*Fax* : /(+1)-858-458-1847/
*Web page *: www.sccn.ucsd.edu/~arno <http://www.sccn.ucsd.edu/%7Earno>
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