Matlab codes

MATLAB CODE FOR LOW PASS BUTTERWORTH IIR FILTER USING BILINEAR TRANSFORM TECHNIQUE.

2011-05-16T04:35:00.000-07:00

clc;

clear all;

close all;

Ap=input('Enter the passband ripple in db:\n');

As=input('Enter the stopband attenuation in db:\n');

Wp=input('Enter the pass band edge frequency in rad:\n');

Ws=input('Enter the stop band edge frequency in rad:\n');

Fs=input('Enter sampling frequency in Hz:\n');

Omgp=2*Fs*tan(Wp/2);

Omgs=2*Fs*tan(Ws/2);

[N,W]=buttord(Omgp,Omgs,Ap,As,'s');

[num,den]=butter(N,Ap,W,'low','s');

[B,A]=bilinear(num,den,Fs);

w=0:0.01:pi;

[h,ph]=freqz(B,A,w);

m=20*log(abs(h));

an=angle(h);

subplot(211);

plot(ph/pi,m);

grid;

xlabel('Frequency in Hz');

ylabel('Gain in db');

title('Frequency response of the Chebyshev filter');

subplot(212);

plot(ph/pi,an);

grid;

ylabel('Phase in rad');

xlabel('Frequency in Hz');

MATLAB CODE FOR LOW PASS BUTTERWORTH IIR FILTER USING IIT TECHNIQUE.

2011-05-16T04:33:00.000-07:00

clc;

clear all;

close all;

Ap=input('Enter the passband ripple in db:\n');

As=input('Enter the stopband attenuation in db:\n');

Wp=input('Enter the pass band edge frequency in rad:\n');

Ws=input('Enter the stop band edge frequency in rad:\n');

Fs=input('Enter sampling frequency in Hz:\n');

Omgp=Wp*Fs;

Omgs=Ws*Fs;

[N,W]=buttord(Omgp,Omgs,Ap,As,'s');

[num,den]=butter(N,Ap,W,'low','s');

[B,A]=impinvar(num,den,Fs);

w=0:0.01:pi;

[h,ph]=freqz(B,A,w);

m=20*log(abs(h));

an=angle(h);

subplot(211);

plot(ph/pi,m);

grid;

xlabel('Frequency in Hz');

ylabel('Gain in db');

title('Frequency response of the Chebyshev filter');

subplot(212);

plot(ph/pi,an);

grid;

ylabel('Phase in rad');

xlabel('Frequency in Hz');

MATLAB CODE FOR LOW PASS CHEBYSHEV IIR FILTER USING BILINEAR TRANSFORM TECHNIQUE.

2011-05-16T04:29:00.000-07:00

clc;

clear all;

close all;

Ap=input('Enter the passband ripple in db:\n');

As=input('Enter the stopband attenuation in db:\n');

Wp=input('Enter the pass band edge frequency in rad:\n');

Ws=input('Enter the stop band edge frequency in rad:\n');

Fs=input('Enter sampling frequency in Hz:\n');

Omgp=2*Fs*tan(Wp/2);

Omgs=2*Fs*tan(Ws/2);

[N,W]=cheb1ord(Omgp,Omgs,Ap,As,'s');

[num,den]=cheby1(N,Ap,W,'low','s');

[B,A]=bilinear(num,den,Fs);

w=0:0.01:pi;

[h,ph]=freqz(B,A,w);

m=20*log(abs(h));

an=angle(h);

subplot(211);

plot(ph/pi,m);

grid;

xlabel('Frequency in Hz');

ylabel('Gain in db');

title('Frequency response of the Chebyshev filter');

subplot(212);

plot(ph/pi,an);

grid;

ylabel('Phase in rad');

xlabel('Frequency in Hz');

MATLAB CODE FOR LOW PASS CHEBYSHEV IIR FILTER USING IIT TECHNIQUE.

2011-05-15T07:08:00.000-07:00

clc;

clear all;

close all;

Ap=input('Enter the passband ripple in db:\n');

As=input('Enter the stopband attenuation in db:\n');

Wp=input('Enter the pass band edge frequency in rad:\n');

Ws=input('Enter the stop band edge frequency in rad:\n');

Fs=input('Enter sampling frequency in Hz:\n');

Omgp=Wp*Fs;

Omgs=Ws*Fs;

[N,W]=cheb1ord(Omgp,Omgs,Ap,As,'s');

[num,den]=cheby1(N,Ap,W,'low','s');

[B,A]=impinvar(num,den,Fs);

w=0:0.01:pi;

[h,ph]=freqz(B,A,w);

m=20*log(abs(h));

an=angle(h);

subplot(211);

plot(ph/pi,m);

grid;

xlabel('Frequency in Hz');

ylabel('Gain in db');

title('Frequency response of the Chebyshev filter');

subplot(212);

plot(ph/pi,an);

grid;

ylabel('Phase in rad');

xlabel('Frequency in Hz');