tmp611.m

信号分析与处理的一些源代码

%MATLAB PROGRAM 6-11
clf
%Estimate PSD by Maxmum Entropy Method(MEM)
%=========================================
N=1024;
Nfft=256;
Fs=1000;
n=0:N-1;
t=n/Fs;
randn('state',0)
xn=sin(2*pi*50*t)+2*sin(2*pi*120*t)+randn(1,N);
[Pxx1,f]=pmem(xn,14,Nfft,Fs);
subplot(211)
plot(f,10*log10(Pxx1))
xlabel('Frequency (Hz)');
ylabel('Power Spectrum (dB)');
title('Maxmum Entropy Method(MEM) Oder=14')
grid

%Estimate PSD by Welch'method
%============================
N=1024;
Nfft=256;
Fs=1000;
n=0:N-1;
t=n/Fs;
randn('state',0)
xn=sin(2*pi*50*t)+2*sin(2*pi*120*t)+randn(1,N);
window=hanning(256);
noverlap=128;
dflag='none';
subplot(212)
psd(xn,Nfft,Fs,window,noverlap,dflag);