[FieldTrip] logic behind normalizing tapers

David Groppe dgroppe at cogsci.ucsd.edu
Sat Jan 15 23:43:29 CET 2011

Hi again Fieldtrippers,
   I noticed that when estimating power spectra ft_specest_mtmfft.m
scales tapers such that their sum squared value is 1 before applying
them to the data.  For example:

%lines 106-108 of ft_specest_mtmfft.m
  case 'hanning'
    tap = hanning(ndatsample)';
    tap = tap./norm(tap, 'fro');

I realize this simply scales the power spectrum, but what's the
rationale for this?  Other EEG analysis software and tutorials I've
read don't do this.
        much thanks,

David Groppe, Ph.D.
dgroppe at cogsci.ucsd.edu

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