matlab中wavread音频分析

[y,Fs,bits]=wavread('luojie3.wav');
 
y=y(:,1);
 
sigLength=length(y);
 
Y = fft(y,sigLength);
 
Pyy = Y.* conj(Y) / sigLength;
 
halflength=floor(sigLength/2);
 
f=Fs*(0:halflength)/sigLength;
 
figure;plot(f,Pyy(1:halflength+1));xlabel('Frequency(Hz)');
 
t=(0:sigLength-1)/Fs;
 
figure;plot(t,y);xlabel('Time(s)');