function [tfr,t,f]=tfrideal(iflaws,t,N,trace)%TFRIDEAL Ideal TFR for given instantaneous frequency laws.%	[TFR,T,F]=TFRIDEAL(IFLAWS,T,N,TRACE) generates the ideal%	time-frequency representation corresponding to the%	instantaneous frequency laws of the components of a signal. %%	IFLAWS : (M,P)-matrix where each column corresponds to%		 the instantaneous frequency law of an (M,1)-signal,%		 These P signals do not need to be present at the same time.%		 The values of IFLAWS must be between 0 and 0.5.%	T      : the time instant(s)      (default : 1:M).%	N      : number of frequency bins (default : M).%	TRACE  : if nonzero, the progression of the algorithm is shown%                                         (default : 0).%	TFR    : output time-frequency matrix, of size (N,length(t)).%		 If nargout=0, a contour plot of TFR is automatically%		 displayed on the screen.%	F      : vector of normalized frequencies.%%	Example :%         N=140; t=0:N-1; [x1,if1]=fmlin(N,0.05,0.3); %         [x2,if2]=fmsin(70,0.35,0.45,60);%         if2=[zeros(35,1)*NaN;if2;zeros(35,1)*NaN];%         tfrideal([if1 if2]); %%	See also PLOTIFL, PLOTSID, and all the time-frequency %        representations listed in the CONTENTS file (TFR*)%	O. Lemoine, F. Auger - March, April 1996.%	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;[ifrow,ifcol]=size(iflaws);if (nargin==1), t=1:ifrow; N=ifrow; trace=0;elseif (nargin==2), N=ifrow; trace=0;elseif (nargin==3), trace=0;end;[trow,tcol]=size(t);if (trow~=1), error('T must only have one row'); end;tfr=zeros(N,tcol);if any(any(iflaws>0.5)) | any(any(iflaws<0)), error('The values of IFLAWS must be between 0 and 0.5');endif trace, disp('Ideal time-frequency distribution'); end;for icol=1:tcol, if trace, disprog(icol,tcol,10); end; ti= t(icol);  for fi=1:ifcol,  if isnan(iflaws(ti,fi)),   tfr(fi,icol)=NaN;  else   tfr(round(iflaws(ti,fi)*2*(N-1))+1,icol)=1;  end endend;if (nargout==0), f=(0:N-1)/(2*N);  axes(gca); contour(t,f,tfr,1,'y'); xlabel('Time'); ylabel('Normalized frequency'); title('Ideal time-frequency representation'); grid;elseif (nargout==3), f=(0.5*(0:N-1)/N)';end;