MATLAB編程判定系統的時不變特性

clf;

n?=?0:50;

Delay?=?12;

x1?=?2*cos(0.4*pi.*n)+3*cos(0.9*pi.*n);

x2?=?[zeros(1,Delay)?x1];

den?=?[?1?-0.4?0.5];

num?=?[2.24?2.4?2.2];

ic?=?[0?0];

y1?=?filter(num,den,x1,ic);

y2?=?filter(num,den,x2,ic);

y2Delay?=?y2(Delay+1:length(n)+Delay);

yd?=?y1-y2Delay;

figure;

subplot(311);stem(y1);title('y1(n)');

subplot(312);stem(y2);title('y2(n)');

subplot(313);stem(yd);title('y1(n)-y2(n+12)');