Mercurial > hg > ltpda
view m-toolbox/classes/+utils/@math/dft.m @ 23:a71a40911c27 database-connection-manager
Update check for repository connection parameter in constructors
author | Daniele Nicolodi <nicolodi@science.unitn.it> |
---|---|
date | Mon, 05 Dec 2011 16:20:06 +0100 |
parents | f0afece42f48 |
children |
line wrap: on
line source
% DFT Compute discrete fourier transform at a given frequency %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % DFT Compute discrete fourier transform at a given frequency % It is defined as % X(f) = T*sum(x(t)*exp(-1i.*2.*pi.*f.*T.*t))|t=0,...,N-1 % where T is the sampling time % % CALL % % Gf = utils.math.dft(gt,f,T) % % INPUT % % - gt, input data series, Nx1 double % - f, a frequency point in Hz, 1x1 double % - T, sampling time in seconds, 1x1 double % % REFERENCES % % D. B. Percival and A. T. Walden, Spectral Analysis for Physical % Applications (Cambridge University Press, Cambridge, 1993) p 108. % % L Ferraioli 09-03-2011 % % $Id: dft.m,v 1.2 2011/03/29 15:36:43 luigi Exp $ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function Gf = dft(gt,f,T) [nn,mm] = size(gt); if nn<mm % willing to work with columns gt = gt.'; end N = numel(gt); t = 0:N-1; ar = exp(-1i.*2.*pi.*f.*T.*t); Gf = T*(ar*gt); end