Date: 03/07/2002 at 10:12:27 From: E Laurie Subject: Power spectra What are Walsh Spectra? I'm starting from scratch here.
Date: 03/07/2002 at 11:26:52 From: Doctor Douglas Subject: Re: Power spectra Hi, Ewan. Thanks for submitting your question to the Math Forum. You may be familiar with Fourier spectra, which specify the amplitude (and phase) of various sinusoidal functions in a given input. Walsh spectra are similar, except that instead of sinusoidal functions, Walsh functions are used. These are piecewise constant (equal to +1 or -1) and relatively simple to describe. Like sinusoidal functions, they form a complete and orthogonal set, which makes them useful for function decomposition. For more information on Walsh functions, take a look at: Mathworld - Eric Weisstein's World of Mathematics http://mathworld.wolfram.com/WalshFunction.html Carlos A. Cunha Filho - Model decomposition with Walsh functions in nonlinear traveltime inversion http://sepwww.stanford.edu/public/docs/sep70/carlos1/paper_html/node5.html I hope this helps you get started. - Doctor Douglas, The Math Forum http://mathforum.org/dr.math/
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