iir_realization.m

经典《信号与系统》教程的matlab例程,对深入理解信号与系统相关概念有很大帮助

clear,close all;
n=0:100;x=u(n)-2*u(n-50);
num=[7.0924  -11.8072    5.0763];
den=[1.0000   -0.3092   -0.7108];
[H,w]=freqz(num,den);
h=impz(num,den,n);

subplot(221)
plot(w/pi,abs(H))
subplot(222)
%plot(w1,abs(H1))
stem(n,x,'r.')
%axis([0,5,0,1.2])

subplot(223)
n=0:100;

y1=filter(num,den,x);
stem(n,abs(y1),'.')
%axis([0,50,0,1.2])
subplot(224)
%x=u(n);
y=zeros(1,101);
wn_1=0;wn_2=0;
for i=1:101;
    wn=x(i)+0.3092*wn_1+0.7108*wn_2;
    y(i)=7.0924*wn-11.8072*wn_1+5.0763*wn_2;
    wn_2=wn_1;
    wn_1=wn;    
    stem(n,y,'r.'),hold on;
    %axis([0,50,-2,2])
    %pause
end