tmp608.m

信号分析与处理的一些源代码

%MATLAB PROGRAM 6-8
clf
%Estimate PSD by Averaged Modified periodogram
%Welch's Method
%=============================================

N=1024;
Nfft=256;
Fs=1000;
n=0:N-1;
t=n/Fs;
window=hanning(256);
noverlap=128;
dflag='none';
xn=sin(2*pi*50*t)+2*sin(2*pi*120*t)+randn(1,N);
Pxx=psd(xn,Nfft,Fs,window,noverlap,dflag);
%=======================
%Create frequency vector
%=======================
f=(0:Nfft/2)*Fs/Nfft;
subplot(211)
plot(f,10*log10(Pxx))
xlabel('Frequency (Hz)');
ylabel('Power Spectrum (dB)');
title('PSD--Welch Method')
grid

[Pxx,f]=psd(xn,Nfft,Fs,window,noverlap,dflag);
subplot(212)
plot(f,10*log10(Pxx))
xlabel('Frequency (Hz)');
ylabel('Power Spectrum (dB)');
title('PSD--Welch Method')
grid