8.m

已知一个LTI系统的差分方程为： y[n]-1.143*y[n-1]+0.4128*y[n-2]=0.0675*x[n]+0.1349*x[n-1]+0.0675*x[n-2] 初始条件y(-1

c=1.1119
y=[1];
x=[c];
k=(c-1)/2;
b=k*poly(y);
a=poly(x);
w=linspace(0,pi,512);
h=freqz(b,a,w);
plot(w,abs(h));