Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!bionet!agate!shelby!csli!poser
From: poser@csli.Stanford.EDU (Bill Poser)
Newsgroups: comp.dsp
Subject: Re: FFT / FHT (was Re: Adjust-Speed CD player?)
Summary: Description of Fast Hartley Transform
Keywords: Hartley Fourier
Message-ID: <10471@csli.Stanford.EDU>
Date: 29 Sep 89 04:14:50 GMT
References: <698@lakart.UUCP>
Sender: poser@csli.Stanford.EDU (Bill Poser)
Reply-To: poser@csli.stanford.edu (Bill Poser)
Organization: Center for the Study of Language and Information, Stanford U.
Lines: 8

The Fast Hartley Transform is described in great detail in
Ronald Bracewell's recent book _The Hartley Transform_. Mathematically,
the Hartley transform is like the Fourier Transform but has a real
kernel, that is, cos + sin instead of cos + i sin. It is therefore not
the same as the Fourier Transform. However, the MAGNITUDE of the
Hartley Transform is the same as that of the Fourier Transform. In the
many cases in which one only cares about the magnitude, not the phase, 
the Fourier Transform may be replaced by the Hartley transform.