1.Bilinear clc; clear all; close all; b=[0.5266]; a=[1 1.03 0.5266]; fs=100; [bz,az]=bilinear(b,a,fs); 2.Butter worth Band stop clc; clear all; close all; fp1=200; fp2=400; fs1=100; fs2=500; Fs=2000; Wp1=2*fp1/Fs; Wp2=2*fp2/Fs; Ws1=2*fs1/Fs; Ws2=2*fs2/Fs; Rp=2; Rs=20; [N,Wc]=buttord([Wp1,Wp2],[Ws1,Ws2],Rp,Rs); [b,a]=butter(N,Wc,'stop'); w=0:0.1:pi; [h,omega]=freqz(b,a,w,'whole'); subplot(2,1,1); plot(omega/pi,20*log10(abs(h))) xlabel('omega/pi'); ylabel('Gain,db'); title(sprintf('N=%d Butterworth Lowpass Filter',N)); grid on; an=angle(h); subplot(2,1,2); plot(omega/pi,unwrap(an)); grid on; xlabel('normalized frequency'); ylabel('phase in radians'); 3.Butter worth Band pass clc; clear all; close all; fp1=200; fp2=400; fs1=100; fs2=500; Fs=2000; Wp1=2*fp1/Fs; Wp2=2*fp2/Fs; Ws1=2*fs1/Fs; Ws2=2*fs2/Fs; Rp=2; Rs=20; [N,Wc]=buttord([Wp1,Wp2],[Ws1,Ws2],Rp,Rs); [b,a]=butter(N,Wc); w=0:0.1:pi; [h,omega]=freqz(b,a,w,'whole'); subpl