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From: cpenrose@sdcc13.ucsd.edu (Christopher Penrose)
Newsgroups: comp.dsp
Subject: Re: What transform to use to get good audio spectra?
Keywords: spectra, transform, phase vocoder
Message-ID: <12909@sdcc6.ucsd.edu>
Date: 2 Oct 90 04:06:23 GMT
References: <1990Oct1.130615.5802@funet.fi>
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In article <1990Oct1.130615.5802@funet.fi> kuusama@news.funet.fi.tut.fi (Kuusama Juha) writes:
>The question: does anybody have a transform that gives the spectrum at
>user definable points, at points evenly spaced on logarithmic scale or
>something? 

With a large enough table size, the phase vocoder can find the actual 
instantaneous frequencies of a signal (as averaged within the table size).
Using a table size of 4096 or 8192 works fairly well for me.  You can find
a good phase vocoder in the book:

Elements of Computer Music
F. Richard "Dick" Moore
Prentice-Hall