MATLAB program for the design and implementation of Butterworth band pass filter

Program code

clc;

clear all;

close all;

fp1=input ('Please input the first pass band frequency = ');

fs1=input ('Please input the first stop band frequency = ');

fp2=input ('Please input the second pass band frequency = ');

fs2=input ('Please input the second stop band frequency = ');

rp=input ('Please input the pass band attenuation = ');

rs=input ('Please input the stop band attenuation = ');

sf=input ('Please input the sampling frequency = ');

p1=2*fp1/sf;

s1=2*fs1/sf;

p2=2*fp2/sf;

s2=2*fs2/sf;

p=[p1,p2];

s=[s1,s2];

[n,w]=buttord(p,s,rp,rs);

[f1,f2]=butter (n,w,'bandpass');

freqz(f1,f2);

title ('Butterworth Band Pass Filter');

Example of output

Please input the first pass band frequency = 2000

Please input the first stop band frequency = 1700

Please input the second pass band frequency = 3000

Please input the second stop band frequency = 3200

Please input the pass band attenuation = 0.5

Please input the stop band attenuation = 60

Please input the sampling frequency = 9000

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MATLAB program for the design and implementation of Butterworth high pass filter

Program code

clc;
clear all;
close all;
fp=input('Please enter the first pass band frequency: ');
fs=input('Please enter the first stop band frequency: ');
rp=input('Please enter the pass band attenuation: ');
rs=input('Please enter the stop band attenuation: ');
sf=input('Please enter the sampling frequency: ');
wp=2*fp/sf;
ws=2*fs/sf;
[n,wn]=buttord(wp,ws,rp,rs);
[b,a]=butter(n,wn,'high');
freqz(b,a);
title('Butterworth High Pass Filter');

Example of output

Please enter the first pass band frequency: 2000

Please enter the first stop band frequency: 1300

Please enter the first pass band attenuation: 0.35

Please enter the first stop band attenuation: 50

Please enter the sampling frequency: 8000

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MATLAB program for the design and implementation of Butterworth low pass filter

Program code

clc;
clear all;
close all;
fp=input('Please enter the first pass band frequency: ');
fs=input('Please enter the first stop band frequency: ');
rp=input('Please enter the pass band attenuation: ');
rs=input('Please enter the stop band attenuation: ');
sf=input('Please enter the sampling frequency: ');
wp=2*fp/sf;
ws=2*fs/sf;
[n,wn]=buttord(wp,ws,rp,rs);
[b,a]=butter(n,wn,'low');
freqz(b,a);
title('Butterworth Low Pass Filter');

Example of output

Please enter the first pass band frequency: 2000

Please enter the first stop band frequency: 1600

Please enter the pass band attenuation: .5

Please enter the stop band attenuation: 53

Please enter the sampling frequency: 9500

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