test0806stft1.asv

信号处理实例

%---------------------------------------------------------------------------------------
% test0806stft1.m,  for  example 08.06
% gauss moderated chirp signal and its STFT
% 2006.12.18 LYB
%----------------------------------------------------------------------------------------
clear;
n=128
%------------------------
% example1:two sinus signal
%w=pi/4; %f=1,fs=32
%t=1:n;w1=t*w; part=n/2;
 %  for k=1:part; sig(k)=sin(k*w); end;
 %  for k=(part+1):2*part, sig(k)=sin(2*k*w); end;
% sig=sig';
%------------------------
% example2:gauss moderated chirp signa
sig=amgauss(n,70,15).*fmlin(n); 

%------------------------
% example3:chirp signa
%sig=fmlin(n); 

p=8;
for ni=1:p
    N=2^ni-1;
    %h=ones(N,1);
    h=hanning(N);
%tfrstft(sig,1:128,128,h);
    [TFR,T,F]=tfrstft(sig,1:n,n,h);
    %figure(4);
    subplot(3,p/2,ni+4);
    imagesc(T,F,abs(TFR(1:n/2,1:n)).^2);
    title(['N=',num2str(N)]);
    hidden off;
    clear TFR;
end


ftreal=abs(fft(sig));
subplot(3,2,1);
plot(real(sig(1:)));

subplot(3,2,2);
plot(ftreal);

%tfrreal=abs(TFR);
%figure(3);
%subplot(211);
%plot(ftreal);
%subplot(212);
%plot(tfrreal(1:127,1))

%imagesc(abs(TFR).^2);