movpwjph.m

用于信号处理里面的时频分析

function M=movpwjph(N,Np,typesig);
%MOVPWJPH Influence of a jump of phase on the interferences of the pWVD.  
%	M=MOVPWJPH(N,Np,TYPESIG) generates the movie frames illustrating the 
%	influence of a jump of phase in different frequency modulations
%	on the interference terms of the pseudo Wigner-Ville distribution.
%
%	N : number of points for the signal;
%	Np : number of snapshots (default : 7)
%	TYPESIG : type of signal :
%	 'C' : constant frequency modulation (default value) ;
%	 'L' : linear frequency modulation ;
%	 'S' : sinusoidal frequency modulation.
%	M : matrix of movie frames.
%
%	Example : 
%	 M=movpwjph(128,8,'S'); movie(M,10);

%	O. Lemoine - May 1996.
%	Copyright (c) 1996 by CNRS (France).
%
%  This program is free software; you can redistribute it and/or modify
%  it under the terms of the GNU General Public License as published by
%  the Free Software Foundation; either version 2 of the License, or
%  (at your option) any later version.
%
%  This program is distributed in the hope that it will be useful,
%  but WITHOUT ANY WARRANTY; without even the implied warranty of
%  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%  GNU General Public License for more details.
%
%  You should have received a copy of the GNU General Public License
%  along with this program; if not, write to the Free Software
%  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

if nargin<1,
 error('At least one argument required');
elseif nargin==1,
 typesig='C'; Np=8;
elseif nargin==2,
 typesig='C'; 
end

M  = moviein(Np);

typesig=upper(typesig);

if typesig=='C',

for k=1:Np,
 sig=[fmconst(N/2);fmconst(N/2)*exp(j*2*pi*k/Np)];
 [tfr,t,f]=tfrpwv(sig); 
 Max=max(max(tfr));V=[0.3 0.5 0.7 0.9]*Max;
 contour(t,f,tfr,V);xlabel('Time'); ylabel('Frequency'); 
 title('Pseudo Wigner-Ville distribution'); axis('xy')
 M(:,k) = getframe;
end

elseif typesig=='L',

for k=1:Np,
 sig=[fmlin(N/2,0,0.25);fmlin(N/2,0.25,0.5)*exp(j*2*pi*k/Np)];
 [tfr,t,f]=tfrpwv(sig); 
 Max=max(max(tfr));V=[0.3 0.5 0.7 0.9]*Max;
 contour(t,f,tfr,V);xlabel('Time'); ylabel('Frequency'); 
 title('Pseudo Wigner-Ville distribution'); axis('xy')
 M(:,k) = getframe;
end

elseif typesig=='S',

sig=fmsin(N,0.05,0.45);
sig1=sig(1:N/2);
sig2=sig(N/2+1:N);
for k=1:Np,
 sig=[sig1;sig2*exp(j*2*pi*k/Np)];
 [tfr,t,f]=tfrpwv(sig); 
 Max=max(max(tfr));V=[0.3 0.5 0.7 0.9]*Max;
 contour(t,f,tfr,V);xlabel('Time'); ylabel('Frequency'); 
 title('Pseudo Wigner-Ville distribution'); axis('xy')
 M(:,k) = getframe;
end

else

error('Wrong input parameter for TYPESIG');

end