위의 시스템 함수에 대해 imp_invr 함수를 사용해보자.

ex8_10.cem

/*  Chapter 8: Example 8.10*/
 c = [1,1]; d = [1,5,6]; T = 0.1; Fs = 1/T;
 [b,a] = implinv(c,d,T) 
// Impulse response of the digital filtert = [0:3:0.01]; 
h=impulse(c,d,t); 
//subplot(2,1,1);plot(t,h);
 
% Magnitude Response of the digital filter
[db,magd,pha,grd,wd] = mfreq_z(b,a);
//plot(wd/(2*pi)*Fs,magd) 
% Impulse response of the analog filter
subplot(2,1,1); plot(t,h); 
holdon;
n = [0:3/T]; hn = filter(b,a,implseq(0,0,3/T));
stem(n*T,hn,"-"); 
title ("Impulse Responses");
xtitle("time in sec");  ytitle("Amplitude");
holdoff;
 
% magnitude response of the analog filter
[db,mags,pha,ws] = mfreq_s(c,d,2*pi*Fs);
subplot(2,1,2); plot(ws/(2*pi),mags*Fs,wd/(2*pi)*Fs,magd)
title("Magnitude Responses");
xtitle("frequency in Hz"); ytitle("Magnitude");