Wednesday, July 13, 2011

MATLAB Programs 11: Design of an IIR Butterworth filter

Program for the design of an IIR Butterworth filter is given below. The function buttord(), is used to find the filter order and center frequency . Function butter() is used to find the filter coefficients.A low pass filter is implemented. 


%Program to design an IIR Butterworth filter


clear all;
close all;
fp=input('Enter the pass band frequency fp   = ');
fs=input('Enter the stop band frequency fs   = ');
rp=input('Enter the pass band attenuation rp = ');
rs=input('Enter the stop band attenuation rs = ');
f=input ('Enter the sampling frequency f     = ');


wp=2*fp/f;
ws=2*fs/f;


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


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


freqz(b,a,500,f);
TITLE ('Magnitude and phase respose of the IIR butterworth filter');


%output
%Enter the pass band frequency fp   = 1000
%Enter the stop band frequency fs   = 1200
%Enter the pass band attenuation rp = .2
%Enter the stop band attenuation rs = 45
%Enter the sampling frequency f     = 3000









8 comments:

Anonymous said...

hahaha

Anonymous said...

ouis je filtrer des images avec filtre de butterworth,aide moi comment

Anonymous said...

why wp=2*fp/f;
why ws=2*fs/f;

please tell

Anonymous said...

freq/2 is the Nyquist sampling frequency in digital systems

Anonymous said...

hehe

Anonymous said...

fgfg

Montages electroniques said...


ouis je filtrer des images avec filtre de butterworth,aide moi comment

Anonymous said...

Use title not TITLE.

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