Reconstructing signal form powerspctrm

[Eric Maris]

Hi Martin,





is there a function in fieldtrip which allows to reconstruct the signal from
the powspctrm?





Let me answer this question, to take away some load from the shoulders of
Jan-Mathijs, whos is becoming the prime signal processing/source
reconstruction expert on this discussion list.



The answer is that such a function does not exist. In fact, what you ask is
not possible. It is possible to reconstruct a signal from a Fourier
transform (using the inverse Fourier transform), but it is not possible to
reconstruct a signal from the squared amplitude of the Fourier transform
(which is the power spectrum - or at least the most common estimate of the
power spectrum). In the power spectrum the phase information is lost, and
therefore you cannot reconstruct the signal.





Good luck,



Eric






Thanks a lot

best, Martin

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The aim of this list is to facilitate the discussion between users of the
FieldTrip toolbox, to share experiences and to discuss new ideas for MEG and
EEG analysis.

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The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.
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