p2_9.m

《数字信号处理——基于计算机计算方法》的源码

% Program P2_9
% Generate the input sequence
clf;
n = 0:299;
x1 = cos(2*pi*10*n/256);
x2 = cos(2*pi*100*n/256);
x = x1+x2;
% Compute the output sequences
num1 = [0.5 0.27 0.77];
y1 = filter(num1,1,x); % Output of System #1
den2 = [1 -0.53 0.46];
num2 = [0.45 0.5 0.45];
y2 = filter(num2,den2,x); % Output of System #2
% Plot the output sequences
subplot(2,1,1);
plot(n,y1);axis([0 300 -2 2]);
ylabel('Amplitude');
title('Output of System #1'); grid;
subplot(2,1,2);
plot(n,y2);axis([0 300 -2 2]);
xlabel('Time index n'); ylabel('Amplitude');
title('Output of System #2'); grid;