Newsgroups: comp.dsp,sci.image.processing
From: mike@jkms.demon.co.uk (Mike Seabrook)
Path: cantaloupe.srv.cs.cmu.edu!das-news2.harvard.edu!news2.near.net!news.mathworks.com!news.alpha.net!uwm.edu!spool.mu.edu!howland.reston.ans.net!news.sprintlink.net!pipex!peernews.demon.co.uk!jkms.demon.co.uk!mike
Subject: Re: Arbitrary N FFT code
References: <3fopac$n63@news.iastate.edu>
Organization: Jordan Kent
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Date: Tue, 24 Jan 1995 16:03:33 +0000
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In article <3fopac$n63@news.iastate.edu>
           dickw@iastate.edu "Richard Wallingford" writes:

> Does anybody have a reference to some source code for an
> arbitrary length FFT?

The underlying trick of an FFT is to divide data repeatedly in half, until
all that is left is a bunch of DFTs with just 2 points each.  That means
that by definition you need to start with 2^N points (N integer).

If your data does not meet this criterion, you need to bend it to suit
by interpolation.

All is explained, with C examples, in Ifeachor and Jervis as recommended
in another recent thread.
  
-- 
Mike Seabrook                                          mike@jkms.demon.uk
Jordan Kent, Gloucestershire, UK
