function [sig,locatoms]= atoms(N,coord,display);% ATOMS Linear combination of elementary Gaussian atoms.%	[SIG,LOCATOMS] = ATOMS(N,COORD,DISPLAY) %	generates a signal consisting in a linear combination of elementary%	gaussian wave packets. The locations of the time-frequency centers % 	of the different atoms are either fixed by the input parameter COORD %	or successively defined by clicking with the mouse (if NARGIN==1).  % %	N        : number of points of the signal%	COORD    : matrix of time-frequency centers, of the form%		   [t1,f1,T1,A1;...;tM,fM,TM,AM]. (ti,fi) are the %		   time-frequency coordinates of atom i, Ti is its time %		   duration and Ai its amplitude. Frequencies f1..fM should %		   be normalized (between 0 and 0.5). %		   If nargin==1, the location of the atoms will be defined%		   by clicking with the mouse, with the help of a menu. The %		   default value for Ti is N/4.%       DISPLAY    display switch. if DISPLAY=1 a figure is displayed,%                  otherwise nothing is displayed. default value is 1%	SIG      : output signal.%	LOCATOMS : matrix of time-frequency coordinates and durations of the%		   atoms. %%	Example : %	 sig=atoms(128);%	 sig=atoms(128,[32,0.3,32,1;56,0.15,48,1.22;102,0.41,20,0.7]); %	 sig=atoms(128,[32,0.3,32,1;56,0.15,48,1.22;102,0.41,20,0.7],0); %	P. Flandrin, May 1995 - O. Lemoine, February 1996.%	F. Auger - O. Lemoine, June 1996.%       E. Chassande-Mottin, F. Auger, May 1998.%	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 %			    lemoine@alto.unice.fr if ( nargin < 1 ), error ( 'At least one parameter required' ) ;endcomp=computer; % so as to know the running computerMatlabVersion=version; MatlabVersion=str2num(MatlabVersion(1));%if MatlabVersion<5,% error('Unfortunately, this version does not run on matlab 4.');%end;if (nargin<3), display=1; end;sig=(1+j)*zeros(N,1);t=linspace(0,2*pi,100); locatoms=[];Natoms=0; choice=1;T=N/4; A=1;if (display==1), clf; set(gcf,'Resize','On','NextPlot','Add'); axsig  = axes('Units','normal','Visible','on','Box','On',...               'position', [0.10 0.65 0.80 0.25],...               'XLim', [1 N], 'XGrid','on', ...               'YLim', [-1 1],'YGrid','on'); axtfr  = axes('Units','normal','Visible','on','Box','On',...               'position', [0.10 0.12 0.80 0.45],...               'XLim',[1 N],  'XGrid','on',...               'YLim',[0 0.5],'YGrid','on'); axes(axtfr); xlabel('Time'); ylabel('Normalized frequency');  hold onend;if (nargin==1), fprintf(' Default value for the time-duration : %f\n',T); fprintf(' Default value for the amplitude     : %f\n',A); while choice~=5,  MaxSig=max(abs(real(sig)));  axes(axsig); plot(1:N, real(sig),'g');  if MaxSig==0.0,   set(axsig,'XLim',[1 N], 'XGrid','on', 'YLim', [-1 1], 'YGrid','on');  else   set(axsig,'XLim',[1 N], 'XGrid','on', 'YLim', [-MaxSig MaxSig],'YGrid','on');  end;  title([int2str(Natoms),' Gaussian atom(s)'])  choice=menu('ATOMS MENU',...              'Add a gaussian atom',...              'Delete the last atom',...              'Change the time-duration',...              'Change the amplitude',...              'Stop');  if choice==1,    axes(axtfr); [t0,f0]=ginput(1);             % add a gaussian atom   t0=round(max(min(t0,N),1)); f0=max(min(f0,0.5),0.0);   locatoms=[locatoms; t0 f0 T A];   axes(axtfr); plot(t0,f0,'x'); plot((t0+j*f0)+(0.5*T*cos(t)+j*(2/(T*pi))*sin(t)))   sig=sig + A*amgauss(N,t0,T) .* fmconst(N,f0,t0);   Natoms=Natoms+1;  elseif (choice==2 & Natoms>=1),              % delete last atom   t0=locatoms(Natoms,1);   f0=locatoms(Natoms,2);   Told =locatoms(Natoms,3);   Aold =locatoms(Natoms,4);   axes(axtfr); AxtfrChildren=get(gca,'Children'); delete(AxtfrChildren(1:2));    if (Natoms==1)    Natoms=0; locatoms=[]; sig=(1+j)*zeros(N,1);   else    sig=sig - Aold*amgauss(N,t0,Told) .* fmconst(N,f0,t0);    Natoms=Natoms-1;    locatoms=locatoms(1:Natoms,:);   end;  elseif choice==3,   fprintf(' Old time duration : %f\n', T);   Told=T; T=input(' New time duration : ');   if isempty(T), T=Told; end;  elseif choice==4,   fprintf(' Old amplitude : %f\n', A);   Aold=A; A=input(' New amplitude : ');   if isempty(A), A=Aold; end;  end end;elseif (nargin>=2), [Natoms,ccoord]=size(coord); if (ccoord~=4),  error('Bad dimension for COORD'); end; for k=1:Natoms,  t0=round(max(min(coord(k,1),N),1));  f0=max(min(coord(k,2),0.5),0.0);  T=coord(k,3); A=coord(k,4);  if t0~=coord(k,1),   disp('Warning : ti should be between 1 and N');  elseif f0~=coord(k,2),   disp('Warning : fi should be between 0 and 0.5');  elseif T<0,   error('T must be positive');  elseif A<0,   error('A must be positive');  else   sig=sig+A*amgauss(N,t0,T) .* fmconst(N,f0,t0);    if (display==1),    axes(axtfr); plot(t0,f0,'x');    plot((t0+j*f0)+(0.5*T*cos(t)+j*(2/(T*pi))*sin(t)))   end;  end end locatoms=coord;endif (display==1), hold off MinSig=min(real(sig)); MaxSig=max(real(sig)); axes(axsig); plot(1:N, real(sig),'g'); if MaxSig==0.0,  set(axsig,'XLim',[1 N], 'XGrid','on', 'YLim', [-1 1], 'YGrid','on'); else  set(axsig,'XLim',[1 N], 'XGrid','on', 'YLim', [-MaxSig MaxSig],'YGrid','on'); end; title([int2str(Natoms),' Gaussian atom(s)'])end;