//Example 5.5
//To Design an Analog Butterworth Filter
clear;
clc ;
close ;
op=0.2*%pi;
os=0.4*%pi;
e1=0.9;
l1=0.2;
epsilon=sqrt(1/(e1^2)-1);
lambda=sqrt(1/(l1^2)-1);
N=log(lambda/epsilon)/log(os/op);
disp(ceil(N),'Order of the filter, N =');
s=%s;
HS=1/((s^2+0.76537*s+1)*(s^2+1.8477*s+1));//Transfer Function for N=4
oc=op/epsilon^(1/ceil(N));
HS1=horner(HS,s/oc);
disp(HS1,'Normalized Transfer Function, H(s) =');