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Re: separating odd/even harmonics

On Thu, Jul 18, 2002 at 11:16:02AM +0200, gia_BERLIN wrote:
> Hi all,
> I am in need of Matlab code to separating odd/even harmonics of
> quasi-periodic complex sounds (saving them in two Wav files) for use as
> experimental stimuli, while preserving the temporal dynamics. Who has some
> matlab code for their favorite technique?

Hi Chen-Gia,

Sorry, I don't have matlab or octave.org code for it, however I would
think that it is possible to implement a 'comb filter' which will do
exactly  what you require.
A comb filter is a type of filter which has maxima points seperated by
minima points in the frequency spectrum. It looks like this :
Where the x label should be 'Frequency' and the y label should be

If you design a comb filter which has minima seperated by 2f, where f is
the fundamental frequency (of the harmonic spectrum), then you will have
a filter which will remove the odd (even) harmonics.
Your next step would be to invert the filter in some way such that you
would have a comb filter which would have minima where maxima previously
were, and vice versa. This would seperate out the even (odd) harmonics.

Unfortunatly I don't have time to help you implement this as I am in
the middle of writing up my PhD thesis, but next year I should !

good luck

> Thanks,
> Chen-Gia Tsai


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