Design of FIR Filter Using Rectangular Windows

a.

Design of FIR filter using Rectangular Windows.

% Rectangular Window

clc;

clear all;

rp=input(‘enter the pass band ripple’);

rs= input(‘enter the stop band ripple’);

fp=input(‘enter the pass band frequency’);

fs= input(‘enter the stop band frequency’);

f= input(‘enter the sampling frequency’);

wp=2*fp/f;

ws=2*fs/f;

num=-20*log10(sqrt(rp*rs))-13;

den=14.6*(fs-fp)/f;

n=ceil(num/den);

n1=n+1;

disp(‘window length:’);

disp(n1);

if(rem(n,2)~=2);

n1=n;

n=n-1;

end

y=boxcar(n1);

disp(‘window coeff’);

disp(y’);

%Lowpass filter

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,1);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘lowpass filter’);

%Highpass filter

b=fir1(n,wp,’high’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,2);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘highpass filter’);

%Bandpass filter

wn=[wp ws];

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,3);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandpass filter’);

%Bandstop filter

wn=[wp ws];

b=fir1(n,wp,’stop’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,4);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandstop filter’);

subplot(3,2,5);

stem(y’);

xlabel(‘n1----->’);

ylabel(‘y(n)------>’);

title(‘rectangular window’);

output :

enter Passband ripple=.02

enter Stopband ripple=.04

enter Passband freq=1500

enter Stopband freq=2000

enter Sampling freq=9000

b.

Design of FIR filter using Hamming Windows.

clc;

clear all;

rp=input(‘enter the pass band ripple’);

rs= input(‘enter the stop band ripple’);

fp=input(‘enter the pass band frequency’);

fs= input(‘enter the stop band frequency’);

f= input(‘enter the sampling frequency’);

wp=2*fp/f;

ws=2*fs/f;

num=-20*log10(sqrt(rp*rs))-13;

den=14.6*(fs-fp)/f;

n=ceil(num/den);

n1=n+1;

disp(‘window length:’);

disp(n1);

if(rem(n,2)~=2);

n1=n;

n=n-1;

end

y=hamming(n1);

disp(‘window coeff’);

disp(y’);

%Lowpass filter

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,1);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘lowpass filter’);

%Highpass filter

b=fir1(n,wp,’high’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,2);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘highpass filter’);

%Bandpass filter

wn=[wp ws];

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,3);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandpass filter’);

%Bandstop filter

wn=[wp ws];

b=fir1(n,wp,’stop’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,4);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandstop filter’);

subplot(3,2,5);

stem(y’);

xlabel(‘n1----->’);

ylabel(‘y(n)------>’);

title(‘hamming window’);

output :

enter Passband ripple=.02

enter Stopband ripple=.04

enter Passband freq=1500

enter Stopband freq=2000

enter Sampling freq=9000

c.

Design of FIR filter using Hanning Windows.

clc;

clear all;

rp=input(‘enter the pass band ripple’);

rs= input(‘enter the stop band ripple’);

fp=input(‘enter the pass band frequency’);

fs= input(‘enter the stop band frequency’);

f= input(‘enter the sampling frequency’);

wp=2*fp/f;

ws=2*fs/f;

num=-20*log10(sqrt(rp*rs))-13;

den=14.6*(fs-fp)/f;

n=ceil(num/den);

n1=n+1;

disp(‘window length:’);

disp(n1);

if(rem(n,2)~=2);

n1=n;

n=n-1;

end

y=hanning(n1);

disp(‘window coeff’);

disp(y’);

%Lowpass filter

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,1);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘lowpass filter’);

%Highpass filter

b=fir1(n,wp,’high’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,2);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘highpass filter’);

%Bandpass filter

wn=[wp ws];

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,3);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandpass filter’);

%Bandstop filter

wn=[wp ws];

b=fir1(n,wp,’stop’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,4);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandstop filter’);

subplot(3,2,5);

stem(y’);

xlabel(‘n1----->’);

ylabel(‘y(n)------>’);

title(‘hanning window’);

output :

enter Passband ripple=.02

enter Stopband ripple=.04

enter Passband freq=1500

enter Stopband freq=2000

enter Sampling freq=9000

d.

Design of FIR filter using Kaiser Windows.

% Rectangular Window

clc;

clear all;

rp=input(‘enter the pass band ripple’);

rs= input(‘enter the stop band ripple’);

fp=input(‘enter the pass band frequency’);

fs= input(‘enter the stop band frequency’);

f= input(‘enter the sampling frequency’);

wp=2*fp/f;

ws=2*fs/f;

num=-20*log10(sqrt(rp*rs))-13;

den=14.6*(fs-fp)/f;

n=ceil(num/den);

n1=n+1;

disp(‘window length:’);

disp(n1);

if(rem(n,2)~=2);

n1=n;

n=n-1;

end

y=boxcar(n1);

disp(‘window coeff’);

disp(y’);

%Lowpass filter

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,1);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘lowpass filter’);

%Highpass filter

b=fir1(n,wp,’high’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,2);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘highpass filter’);

%Bandpass filter

wn=[wp ws];

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,3);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandpass filter’);

%Bandstop filter

wn=[wp ws];

b=fir1(n,wp,’stop’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,4);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandstop filter’);

subplot(3,2,5);

stem(y’);

xlabel(‘n1----->’);

ylabel(‘y(n)------>’);

title(‘kaiser window’);

output :

enter Passband ripple=.02

enter Stopband ripple=.04

enter Passband freq=1500

enter Stopband freq=2000

enter Sampling freq=9000

e.

Design of FIR filter using Blackman Windows.

% Rectangular Window

clc;

clear all;

rp=input(‘enter the pass band ripple’);

rs= input(‘enter the stop band ripple’);

fp=input(‘enter the pass band frequency’);

fs= input(‘enter the stop band frequency’);

f= input(‘enter the sampling frequency’);

wp=2*fp/f;

ws=2*fs/f;

num=-20*log10(sqrt(rp*rs))-13;

den=14.6*(fs-fp)/f;

n=ceil(num/den);

n1=n+1;

disp(‘window length:’);

disp(n1);

if(rem(n,2)~=2);

n1=n;

n=n-1;

end

y=blackman(n1);

disp(‘window coeff’);

disp(y’);

%Lowpass filter

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,1);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘lowpass filter’);

%Highpass filter

b=fir1(n,wp,’high’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,2);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘highpass filter’);

%Bandpass filter

wn=[wp ws];

b=fir1(n,wp,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,3);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandpass filter’);

%Bandstop filter

wn=[wp ws];

b=fir1(n,wp,’stop’,y);

[h,omega]=freqz(b,1,256);

m=20*log10(abs(h));

subplot(3,2,4);

plot(omega/pi,m);

xlabel(‘normalized frequency----->’);

ylabel(‘gain in db------>’);

title(‘bandstop filter’);

subplot(3,2,5);

stem(y’);

xlabel(‘n1----->’);

ylabel(‘y(n)------>’);

title(‘blackman window’);

output :

enter Passband ripple=.02

enter Stopband ripple=.04

enter Passband freq=1500

enter Stopband freq=2000

enter Sampling freq=9000