function [tfr,t,f] = tfrpwv(x,t,N,h,trace);%TFRPWV	Pseudo Wigner-Ville time-frequency distribution.%	[TFR,T,F]=TFRPWV(X,T,N,H,TRACE) computes the Pseudo Wigner-Ville  %	distribution of a discrete-time signal X, or the%	cross Pseudo Wigner-Ville representation between two signals. % %	X     : signal if auto-PWV, or [X1,X2] if cross-PWV.%	T     : time instant(s)          (default : 1:length(X)).%	N     : number of frequency bins (default : length(X)).%	H     : frequency smoothing window, in the time-domain,%		H(0) being forced to 1   (default : Hamming(N/4)). %	TRACE : if nonzero, the progression of the algorithm is shown%	                                 (default : 0).%	TFR   : time-frequency representation. When called without %	        output arguments, TFRPWV runs TFRQVIEW.%	F     : vector of normalized frequencies.%%	Example:%	 sig=fmlin(128,0.1,0.4); tfrpwv(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[xrow,xcol] = size(x);if (nargin < 1), error('At least 1 parameter is required');elseif (nargin <= 2), N=xrow;end;hlength=floor(N/4);hlength=hlength+1-rem(hlength,2);if (nargin == 1), t=1:xrow; h = window(hlength); trace=0;elseif (nargin == 2)|(nargin == 3), h = window(hlength); trace=0;elseif (nargin == 4), 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 & nargin==5), fprintf('For a faster computation, N should be a power of two\n');end; [hrow,hcol]=size(h); Lh=(hrow-1)/2; h=h/h(Lh+1);if (hcol~=1)|(rem(hrow,2)==0), error('H must be a smoothing window with odd length');end;tfr= zeros (N,tcol) ;  if trace, disp('Pseudo Wigner-Ville distribution'); end;for icol=1:tcol, ti= t(icol); taumax=min([ti-1,xrow-ti,round(N/2)-1,Lh]); tau=-taumax:taumax; indices= rem(N+tau,N)+1; tfr(indices,icol) = h(Lh+1+tau).*x(ti+tau,1).*conj(x(ti-tau,xcol)); tau=round(N/2);  if (ti<=xrow-tau)&(ti>=tau+1)&(tau<=Lh),  tfr(tau+1,icol) = 0.5 * (h(Lh+1+tau) * x(ti+tau,1) * conj(x(ti-tau,xcol))  + ...                           h(Lh+1-tau) * 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,'tfrpwv',h);elseif (nargout==3), f=(0.5*(0:N-1)/N)';end;