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Re: Sound Analysis Tools

>Since the Fourier transform is linear, the two are equivalent.

As the Fourier transform is windowed, there is always a time/frequency
resolution tradeoff. So, the interpolation is not as accurate as one

>  As I recall,
>it happened to be more convenient to subtract in the frequency domain.

Well, I have to resynthesize the sound anyway. I just synthesize the
sound in a way that allows substraction. It is not very hard.

When I use every peaks (ie when I don't select the harmonic part),
the direct substraction (in the time domain) validate the quality of the
analysis (ie the accuracy of the interpolation). The error of the analysis
equals the remaining signal.

After extracting the harmonic part from the signal, I can study the signal
with other time frequency/resolution tradeoff. This can be efficient to study
transients (high time resolution, low frequency resolution).

>The hard part was creating a properly interpolated window transform,
>matched to the sinusoidal peak in complex amplitude and frequency of

Yes! Properly interpolated means properly interpreted.
The spectrum is convolved with the transform of the window.
The good choice is to choose the window and to interpret its effects
in the frequency domain.

I think that the gaussian is the easiest window to interpret as its
transform is a... gaussian.

Maybe, one can choose another window which simplifies interpolation...


PS I will be on weekend after this post.
   So, good week end and good night(to Europeans).

|                                                             |\
|  Thierry Rochebois           Doctorant                      | +
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|  thierry@ief-paris-sud.fr                                   | |
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