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.