function [tfr,t,f] = tfrwv(x,t,N,trace);%TFRWV	Wigner-Ville time-frequency distribution.%	[TFR,T,F]=TFRWV(X,T,N,TRACE) computes the Wigner-Ville distribution%	of a discrete-time signal X, %	or the cross Wigner-Ville representation between two signals. % %	X     : signal if auto-WV, or [X1,X2] if cross-WV.%	T     : time instant(s)          (default : 1:length(X)).%	N     : number of frequency bins (default : length(X)).%	TRACE : if nonzero, the progression of the algorithm is shown%	                                 (default : 0).%	TFR   : time-frequency representation. When called without %	        output arguments, TFRWV runs TFRQVIEW.%	F     : vector of normalized frequencies.%%	Example :%	 sig=fmlin(128,0.1,0.4); tfrwv(sig);% %	See also all the time-frequency representations listed in%	the file CONTENTS (TFR*)%	F. Auger, May-August 1994, July 1995.%	Copyright (c) 1996 by CNRS (France).%%	------------------- CONFIDENTIAL PROGRAM -------------------- %	This program can not be used without the authorization of its%	author(s). For any comment or bug report, please send e-mail to %	f.auger@ieee.org if (nargin == 0), error('At least one parameter required');end;[xrow,xcol] = size(x);if (nargin == 1), t=1:xrow; N=xrow ; trace=0;elseif (nargin == 2), N=xrow ; trace=0;elseif (nargin == 3), trace = 0;end;if (N<0), error('N must be greater than zero');end;[trow,tcol] = size(t);if (xcol==0)|(xcol>2), error('X must have one or two columns');elseif (trow~=1), error('T must only have one row'); elseif (2^nextpow2(N)~=N), fprintf('For a faster computation, N should be a power of two\n');end; tfr= zeros (N,tcol);  if trace, disp('Wigner-Ville distribution'); end;for icol=1:tcol, ti= t(icol); taumax=min([ti-1,xrow-ti,round(N/2)-1]); tau=-taumax:taumax; indices= rem(N+tau,N)+1; tfr(indices,icol) = x(ti+tau,1) .* conj(x(ti-tau,xcol)); tau=round(N/2);  if (ti<=xrow-tau)&(ti>=tau+1),  tfr(tau+1,icol) = 0.5 * (x(ti+tau,1) * conj(x(ti-tau,xcol))  + ...                           x(ti-tau,1) * conj(x(ti+tau,xcol))) ; end; if trace, disprog(icol,tcol,10); end;end; tfr= fft(tfr); if (xcol==1), tfr=real(tfr); end ;if (nargout==0), tfrqview(tfr,x,t,'tfrwv');elseif (nargout==3), f=(0.5*(0:N-1)/N)';end;