[Eeglablist] RE : Question about time-frequency analysis

[Andre Achim]

Your command should have a "." before the "^". It should read: mbase =
10.^(mbase/10);

A. Achim


-----Message d'origine-----
De : eeglablist-bounces at sccn.ucsd.edu
[mailto:eeglablist-bounces at sccn.ucsd.edu] De la part de Michael Stevens
Envoyé : 19 mai 2008 16:04
À : eeglablist at sccn.ucsd.edu
Objet : [Eeglablist] Question about time-frequency analysis


Hi folks,

I'm trying to use the EEGLAB time-frequency analysis to do a simple
single-trial FFT on EEG data sampled at 500 Hz during an auditory oddball
task.  I've epoched 1000 msec trials around the targets and successfully
called the newtimef.m function to get out 26 frequency bins.  However, I'd
like to look at 'absolute power', not 'dB'.  The function provides an
optional input called 'outputformat' which can be set to provide 'old'
output in 'absolute amplitude'.  I'm pretty sure this is what I want
(right?).

However, my immediate problem is that when I run the code now specifying
'old' output format, it gives me an error:

??? Error using ==> mpower
Matrix must be square.

Error in ==> newtimef at 1750
	mbase = 10^(mbase/10);


So, I'm wondering if I'm specifying something with the code that the 'old'
code can't handle?  I've copied the actual function call below if anyone can
help me.

[ersp,itc,powbase,times,freqs,erpsboot,itcboot] = newtimef(DATA, 500, [-24
976],500,0,'padratio',1,'winsize',256,'outputformat','old');


Many thanks for any suggestions or fixes.  I've got the whole analysis
scripted up to run, but can't get past this problem.

Best regards,
Mike


Michael C. Stevens, Ph.D.

Director, Child and Adolescent Research
The Institute of Living / Hartford Hospital

Director, Clinical Neuroscience & Development Laboratory
Olin Neuropsychiatry Research Center

Assistant Clinical Professor of Psychiatry
Yale University School of Medicine

Contact Information:
200 Retreat Avenue
ONRC, Whitehall Building
Hartford, CT  06106

Tel: (860) 545-7552
Fax: (860) 545-7797


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