[x1,fs1,bits1]=wavread('C:\Documents and Settings\hp\My Documents\MATLAB\ak47-1.wav');
nfft=10240;
psd=abs(fft(x1,nfft));
plot((0:nfft-1)/nfft*fs1,psd);
xlabel('?? f');
ylabel('??? psd');
[s,f,t]=spectrogram(x1);
contour(t,(0:127)/nfft*fs1,abs(s(1:128,:)).^2);
xlabel('?? t');
ylabel('?? f');
figure
mesh(t,(0:127)/nfft*fs1,abs(s(1:128,:)).^2);
xlabel('?? t');
ylabel('?? f');
zlabel('?? A');