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Re: Discrete sine transform [message #30562 is a reply to message #30553]

Thu, 02 May 2002 04:16

Kenneth P. Bowman
Messages: 585
Registered: May 2000

Senior Member

In article <aar135$hqq$1@n.ruf.uni-freiburg.de>,
"Dominik Paul" <dpaul@ukl.uni-freiburg.de> wrote:

> I am not 100% sure about it, but I think the sin transform is just the
> imaginary part of the Fourie Transformation.
>

>> Does anybody have the algorithm for the discrete sine tranform coded
>> in IDL. If I understand correctly it can be done (with some
>> redundency) by using the FFT - but I'm not sure how!

Dominik Paul is correct, but the discrete sine transform is usually
defined from (0, pi) rather than (0, 2 pi). So if your series is of
length N, I think that you need to double the length of the series by
adding N zeros. The coefficients will also need to be adjusted by a
factor of 2 (because your are integrating over a domain that is twice as
large).

Hope that helps,

Ken Bowman

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[Message index]

		Re: Discrete sine transform By: Matthew Angling on Fri, 03 May 2002 00:41
		Re: Discrete sine transform By: mvukovic on Thu, 02 May 2002 08:36
		Re: Discrete sine transform By: Kenneth P. Bowman on Thu, 02 May 2002 04:16
		Re: Discrete sine transform By: Dominik[1] on Thu, 02 May 2002 02:38

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