1 Design Low Pass filter and High Pass filter with corner fr

1. Design Low Pass filter and High Pass filter with corner frequency wc = 50.
2. Design a 4th order Butterworth band pass filter with a center frequency at 20 rad/sec
and a bandwidth of 8 rad/sec. the final answer should be a ratio of polynomials in
descending power of s.

Solution

%to design IIR butterworth filter using bilinear transformation method.

close all;

clear all;

clc;

wp=input(\'enter passband frequency\');

ws=input(\'enter stopband frequency\');

rp=input(\'enter pass band attnuation\');

rs=input(\'enter stopband attenuation\');

t=1;

fs=2000

[n,wn]=buttord(wp,ws,rp,rs,\'s\');

[b,a]=butter(n,wn,\'low\',\'s\');

[bz,az]=bilinear(b,a,fs);

freqz(bz,az,512,fs);

grid on;

gtext(\'kluniversity\');

output :

enter passband frequency 2

enter stopband frequency8

enter pass band attnuation2

enter stopband attenuation8