A.1)b = [1 0.1];a = [1 0.2 9.01];fs = 1/0.1;

for i = 1:2figure(i);[Ha, Wa] = freqs(b,a,512);plot(Wa/(2*pi), 20*log10(abs(Ha)),'.');hold on;xlabel('Frequency');ylabel('Magnitude');[bz, az] = impinvar(b,a,fs);[Hd, Wd] = freqz(bz,az,512,fs);plot(Wd,20*log10(abs(Hd)));legend('Analog filter','Digital filter');fs=1/0.5

end

A.2)b = [1 0.1];a = [1 0.2 9.01];sys = tf(b,a);ts = 0.1;

for i = 1:2figure(i);t = 0:ts:50*i;impulse(sys,t); hold on;fs = 1/ts;[bz, az] = impinvar(b,a,fs);dimpulse(bz,az);ts = 0.5;

end

A.3)b = [1 0.1];a = [1 0.2 9.01];fs = 1/0.1;

for i = 1:2figure(i);[Ha, Wa] = freqs(b,a,512);plot(Wa/(2*pi), 20*log10(abs(Ha)),'.');hold on;xlabel('Frequency');ylabel('Magnitude');[bz, az] = bilinear(b,a,fs);[Hd, Wd] = freqz(bz,az,512,fs);plot(Wd,20*log10(abs(Hd)));legend('Analog filter','Digital filter');fs=1/0.5

end

sys = tf(b,a);ts = 0.1;for i = 3:4

figure(i);t = 0:ts:100;impulse(sys,t); hold on;fs = 1/ts;[bz, az] = bilinear(b,a,fs);dimpulse(bz,az);ts = 0.5;

end

B)%Butterworth filterfs = 8;wp = 1.2/fs;ws = 2/fs;rp = 0.5;rs = 40;[n wn] = buttord(wp,ws,rp,rs)[bz az] = butter(n,wn)w = -5:.01:5;[h w] = freqz(bz,az,w);plot(w/(2*pi),abs(h));xlabel('Normalized Frequency(rad)');ylabel('Magnitude(db)');grid on;

%Chebyshev filterfs = 8;wp = 1.2/fs;ws = 2/fs;rp = 0.5;rs = 40;[n wn] = cheb1ord(wp,ws,rp,rs)[bz az] = cheby1(n,rp,wn)w = -5:.01:5;[h w] = freqz(bz,az,w);plot(w/(2*pi),abs(h))xlabel('Normalized Frequency(rad)');ylabel('Magnitude(db)');grid on;

%Elliptic filterfs = 8;wp = 1.2/fs;ws = 2/fs;rp = .5;rs = 40;[n wn] = ellipord(wp,ws,rp,rs)[bz az] = ellip(n,rp,rs,wn)w = -5:.01:5;[h w] = freqz(bz,az,w);plot(w/(2*pi),abs(h));xlabel('Normalized Frequency');ylabel('Magnitude(db)');grid on;