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FFT analyse and other

I would like to know where to get a fast routine which translate FFT
results into original
signal. I'm asking, because i know, that i should have multiplied FFT
results by sine
and cosine, but this way is very slow. Do you know faster way ?

                        X-Pert

My e-mail: xp...@kki.net.pl

 

Re:FFT analyse and other


Quote
Piotr "X-Pert" Wyderski wrote:
> I would like to know where to get a fast routine which translate FFT
> results into original signal.

I think one of the best sources to find answers at questions related to
mathematics & Pascal is the following book:

W.H.Press, B.P. Flannery, S.A. Teukolsky, W.T. Vetterling:
 Numerical Recipes, The Art of Scientific Computing,
 Cambridge University Press, Cambridge, New York 1990

Zoltan

Re:FFT analyse and other


Quote
> I would like to know where to get a fast routine which translate FFT
> results into original
> signal. I'm asking, because i know, that i should have multiplied FFT
> results by sine
> and cosine, but this way is very slow. Do you know faster way ?

Dear Piotr,

     Do you mean the Inverse FFT?  As you probably know, the inverse of a
Fourier
transform looks very similar to the transform itself.  If you have an FFT
routine, it
probably has a "switch" that allows it to do either forward or inverse
transforms.  [Having
said that, I looked at the FFT I submitted to the SWAG -- no such
switch!].

Bob Schor
Pascal Enthusiast

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