p2_6.m

Digital Signal Processing-A Computer-Based Approach(Second Edition)Sanjit K.Mitra实验指导书练习题matlab程序

% Program P2_6.m
% Time Reversal Property of DTFT
close all;clear all;
w = -pi:2*pi/255:pi; num = [1 2 3 4];
L = length(num)-1;
h1 = freqz(num, 1, w); h2 = freqz(fliplr(num), 1, w);
h3 = exp(w*L*i).*h2;
subplot(2,2,1);plot(w/pi,abs(h1));grid
title('Magnitude Spectrum of Original Sequence')
subplot(2,2,2);plot(w/pi,abs(h3));grid
title('Magnitude Spectrum of Time-Reversed Sequence')
subplot(2,2,3);plot(w/pi,unwrap(angle(h1)));grid
title('Phase Spectrum of Original Sequence')
subplot(2,2,4);plot(w/pi,unwrap(angle(h3)));grid
title('Phase Spectrum of Time-Reversed Sequence')