fft2uft.m

beamlet变化的工具箱

function u=FFT2UFT(f)
% UFT2FFT: Convert Fast Fourier Transform to Unbiased Fourier Transform
% 	u = UFT2FFT(f)
% Inputs
%	f		dyadic row vector -- fft(x)
% Outputs
%	u	dyadic row vector -- fft_ua(x)
% Description
%	View the entries of u as containing
%	   y'(-n/2), ... , y'(n/2-1)
% where
%	   y'(k) = Sum( x(j+n/2) exp(-2*pi*i*k*j/n) : -n/2 <= j < n/2)
%	This routine recovers these from the
% values
%		y(0), ..., y(n-1)
% where
%	  y(k) = Sum( x(j) exp(-2*pi*i*k*j/n) : 0 <= j < n)
%
	x = ifft(f);  % cop-out
	u = fft_ua(x);	
%
%	Copyright (c) 1998 David L. Donoho
%

%
% Part of BeamLab Version:200
% Built:Friday,23-Aug-2002 00:00:00
% This is Copyrighted Material
% For Copying permissions see COPYING.m
% Comments? e-mail [e-mail]
%
%
% Part of BeamLab Version:200
% Built:Saturday,14-Sep-2002 00:00:00
% This is Copyrighted Material
% For Copying permissions see COPYING.m
% Comments? e-mail [e-mail]
%