%  ex_11_06_1.m :  習(xí)題 11.6


clear all;
close all;
N=256;
Fs=1;
u=rand(1,N);
u=u-mean(u);
[xpsd,w]=pwelch(u,hamming(64),32,4096,1);        
mmax=max(xpsd);
xpsd=xpsd/mmax;
xpsd=10*log10(xpsd+0.000001);
subplot(211)
plot(w,xpsd);grid on;

[xpsd,w]=pwelch(u,hamming(256),0,4096,1);        
mmax=max(xpsd);
xpsd=xpsd/mmax;
xpsd=10*log10(xpsd+0.000001);
subplot(212)
plot(w,xpsd);grid on;