Fourier decomposition Fwd: from AUDITORY


Subject: Fourier decomposition Fwd: from AUDITORY
From: Kevin Austin (kevin.austin@videotron.ca)
Date: Mon Sep 19 2005 - 13:20:49 EDT


>Date: Sun, 18 Sep 2005 20:15:31 -0500
>From: beaucham <beaucham@MANFRED.MUSIC.UIUC.EDU>
>Subject: Re: Fourier decomposition
>
>What is meant by "accurately"?. ie, how do you test and how close do
>the results have to be before you'd say the analysis method is
>accurate? The method described at
>
>http://ccrma.stanford.edu/~jos/parshl/parshl.html
>
>does a pretty darn good job. We have an implementation similar to
>this in our SNDAN package which performs very well on harmonic and
>inharmonic sounds. See
>
>http://ems.music.uiuc.edu/beaucham/software/sndan/
>
>Regards,
>Jim Beauchamp
>Univ. of Illinois at Urbana-Champaign
>
>On Sat, 17 Sep 2005, Bob Masta wrote:
>
>> On 16 Sep 2005 at 19:20, Fred Herzfeld wrote:
>>
>> > Hello List:
>> >
> > > I am now about to make public some work on signal
>decomposition. As part of the disclosure I will make the statement:
> > > ------------------
> > > It is not possible to accurately recover the coefficients
>(amplitude and phase of the individual harmonics) of a function
>consisting of harmonic sinusoidal components, when the Period of
>the not necessarily present fundamental is not known, by using the
>normal computational procedure of either the Fourier Series or the
>Short term Fourier Transform.
> > > -----------------------
>> >
>> > I would appreciate any and all comments.
> > >
> > Interesting question. Pre-multiplication by ordinary windowing
>> functions seems to do a pretty good job when recovering the
>> magnitudes, but I've never looked into what this does to the
> > phase. I gather from your statement that it screws it up, and
> > that there is no analogous window function for obtaining phase?
>>
>> Thanks for your insights...
>>
>> Bob Masta
>>
>> audioATdaqartaDOTcom
>>
>
>------------------------------
>
>End of AUDITORY Digest - 17 Sep 2005 to 18 Sep 2005 (#2005-186)
>***************************************************************



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