MATLAB: How to use periodogram

periodogramusing

i want to analyse a .wav file using spectral.periodogram, but i have a trouble, what should i do?
x = wavread('balaclava5s.wav'); size(x); N = 350208; Fs = 44100; ts = 1/fs; tmax = (N-1)*ts; t = 0:ts:tmax; periodogram(x)
is it right? i'm new to digital signal processing, and i have no basic.

Best Answer

wavread() will return the sampling frequency. Then you input the sampling frequency into periodogram() (along with the other documented inputs) to get a meaningful frequency vector as an output.
[x,Fs] = wavread('balaclava5s.wav'); 
[Pxx,Freq] = periodogram(x,rectwin(length(x)),length(x),Fs);
plot(Freq,10*log10(Pxx))
grid on;
xlabel('Hz'); ylabel('dB/Hz');
Just
   periodogram(x,rectwin(length(x)),length(x),Fs);
produces a plot without outputting any data.
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