Matlab Program for Finite Impulse Response(FIR) Filter Design

Matlab Program for Finite Impulse Response(FIR) Filter Design:

clc;

close all;

clear all;

n = input('enter the order of filter :');

wc = input('enter the cut off frequency:');

ws=input('enter the sampling frequency:');

disp('1 for low pass');disp('2 for high pass');disp('3 for bandpass');disp('4 for bandstop');

disp('enter the filter type');

filtertype=input('filter type');

switch (filtertype)

    case 1

        ft ='low';

    case 2

        ft='high';

    case 3

        ft='pass';

    case 4

        ft='stop';

    otherwise

        disp('error');

end

disp('1 for rectwin');disp('2 for hamming');disp('3 for hanning');disp('4 for blackman');

disp('enter the window type');

windowtype=input('window type');

switch (windowtype)

    case 1

        wt=rectwin(n+1);

    case 2

        wt=hamming(n+1);

    case 3

        wt=hanning(n+1);

    case 4

        wt=blackman(n+1);

  

 otherwise

        disp('error');

end

figure(1)

b = fir1(n,wc/ws,ft,wt);

freqz(b,1,ws);

n=linspace(0,1,ws);

f1=input('enter the passband frequency:');

f2=input('enter the stopband frenquency:');

x=sin(2*pi*f1*n)+sin(2*pi*f2*n);

xk=fft(x);

figure(2)

subplot(2,2,1);stem(abs(xk));title('spectrum of input signal');xlabel('k');yalabel('X(K)');

y=filter(b,1,x);

yk=fft(y);

subplot(2,2,2);stem(abs(yk));title('spectrum of filtered output signal');xlabel('k');yalabel('y(K) ');

  

OUTPUT:

LOW PASS FILTER:

enter the order of filter :50

enter the cut off frequency:2000

enter the sampling frequency:8000

1 for low pass

2 for high pass

3 for bandpass

4 for bandstop

enter the filter type

filter type1

1 for rectwin

2 for hamming

3 for hanning

4 for blackman

enter the window type

window type1

enter the passband frequency:1200

enter the stopband frenquency:2400 

    

HIGH PASS FILTER:

enter the order of filter :50

enter the cut off frequency:2000

enter the sampling frequency:8000

1 for low pass

2 for high pass

3 for bandpass

4 for bandstop

enter the filter type

filter type2

1 for rectwin

2 for hamming

3 for hanning

4 for blackman

enter the window type

window type2

enter the passband frequency:1300

enter the stopband frenquency:2500

                                                                           

BAND PASS FILTER:

 enter the order of filter :50

enter the cut off frequency:[1500 3000]

enter the sampling frequency:8000

1 for low pass

2 for high pass

3 for bandpass

4 for bandstop

enter the filter type

filter type3

1 for rectwin

2 for hamming

3 for hanning

4 for blackman

enter the window type

window type3

enter the passband frequency:2000

enter the stopband frenquency:3500

BAND STOP FILTER:

enter the order of filter :50

enter the cut off frequency:[1500 3000]

enter the sampling frequency:8000

1 for low pass

2 for high pass

3 for bandpass

4 for bandstop

enter the filter type

filter type4

1 for rectwin

2 for hamming

3 for hanning

4 for blackman

enter the window type

window type4

enter the passband frequency:2000

enter the stopband frenquency:3500