arxinhao_ar.m

主要是BURG法对声信号进行谱估计的程序。 还有利用BURG法求AR模型系数

clear
clf'
clc
N=100;
Fs=500;
%产生x1信号即AR信号
vn=rands(1,N);
xn=zeros(1,N);
xn(1)=vn(1);xn(2)=vn(2);
a1=0.78;
a2=-0.96;
for n=3:N
    xn(n)=vn(n)+a1*xn(n-1)+a2*xn(n-2);
end
p=floor(length(xn)/5);
[a e k]=arburg(xn,p);
[H,w] = freqz(1,a,256);         
subplot(211);
% Hp =plot(w/pi,20*log10(2*abs(H)/(2*pi)),'r-'); 
plot(20*log10(2*abs(H)/(2*pi)));
grid on
title('xn(n)=noise(n)+a1*xn(n-1)+a2*xn(n-2)');

nfft=1024;
[xpsd,f]=pburg(xn,p,nfft,Fs);
pmax=max(xpsd);
xpsd=xpsd/pmax;
xpsd=10*log10(xpsd);
subplot(212);
plot(f,xpsd);
title('Power Spectral estimate with burg');
ylabel('Power Spectral estimate(dB)');
xlabel('f(Hz)');
grid on;
ymin_psd=min(xpsd)-1;
ymax_psd=max(xpsd)+1;
axis([0 300 ymin_psd ymax_psd]);