longteng5.m

用周期图法求出的功率谱曲线和burg算法求出的AR功率谱曲线(p=50)

%用周期图法求出的功率谱曲线和burg算法求出的AR功率谱曲线(p=50)
% author:闫朝星 2007.12.18
% version 0.1
%---------------------------------
fs=200;
n=0:1/fs:1;
xn=cos(2*pi*40*n)+cos(2*pi*41*n)+3*cos(2*pi*90*n)+0.1*randn(size(n));
window=boxcar(length(xn));
nfft=512;
[pxx,f]=periodogram(xn,window,nfft,fs);
subplot(121)
plot(f,10*log10(pxx))
xlabel('frequency(hz)');
ylabel('power spectral density(Db/Hz)');
title('periodogram psd estimate');
order1=50;
range='half';
magunits='db';
subplot(122)
pburg(xn,order1,nfft,fs,range);