信号时频分析简介——短时傅里叶变换

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fs = 5120;N = 32768; dt = 1.0/Fs;
T = dt*N;df = 500.0/N;
t = linspace(0,T,N);
for i = 1:N
    x(i) = sin(2*pi*0.3*i*dt)*sin(2*pi*(500+df*i)*i*dt);
end
plot(x);figure;
Z = spectrogram(x,1024,512);
P = sqrt(Z.*conj(Z));
S = size(P);
X = linspace(0,Fs/2,S(1));
Y = linspace(0,dt*N,S(2));
mesh(X,Y,P');view(15,70);