MATLAB: Design FIR filter using cot off frequency

fir filter

Design a low pass digital FIR filter using Hamming window with length of the filter, N = 9 and a cut off frequency of 1.2 rad/sec. Further plot the magnitude and phase response of the designed filter

Best Answer

Clc;

Clear all;

Close all;

N=9; %number of samples

wc=1.2; %cut of frequncy wc=(2*fc/fs); f=corner freq., fs=sampling freq.

b=fir1(N,wc/pi,hamming(N+1));

w=0:0.01:1.2*pi;

h=freqz(b,1,w);

subplot(211);

plot(w/pi,20*log(abs(h)));

title('Magnitude response(dB)');

xlabel('Frequency(*pi rad/sample)');

ylabel('magnitude in dB');

subplot(212);

plot(w/pi,phase(h));

title('Phase response');

xlabel('Frequency(*pi rad/sec)');

ylabel('Phase in radians');

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MATLAB: Hamming window matlab code

if x is an n-element input signal and t is the time scale
w = 0.54 - 0.46*cos(2*pi*t/(n-1));
wx = x.*w;

MATLAB: Designing IIR Filters using Bilinear Transform

so final and last version of the answer :


N = 2;
fc = [500 1000];
FS = 8000;
fcn = 2*fc/FS;
T = 1/FS;
freq = logspace(2,log10(FS/2.56));
% [ad, bd] = butter(N, fcn); % digital version
[a, b] = butter(N, 2*pi*fc, 's'); % analog version
figure(1); % allows log x 


[g,p]  = bode(a,b,2*pi*freq);grid
subplot(2,1,1),semilogx(freq,20*log10(g));
title('Frequency Response of the Filter')
subplot(2,1,2),semilogx(freq,p);grid
[ad, bd] = bilinear(a, b, FS);
figure(2); freqz(ad,bd,freq,FS);  % allows only lin x 
title('Frequency Response of the Filter')
figure(3); % allows log x 
[g,p]  = dbode(ad,bd,1/FS,2*pi*freq);
subplot(2,1,1),semilogx(freq,20*log10(g));grid
title('Frequency Response of the Filter')
subplot(2,1,2),semilogx(freq,p);grid
% axis([0 4000 -40 1]);
[ad, bd] = butter(N, fcn); % digital version
figure(4); % allows log x 
[g,p]  = dbode(ad,bd,1/FS,2*pi*freq);
subplot(2,1,1),semilogx(freq,20*log10(g));grid
title('Frequency Response of the Filter')
subplot(2,1,2),semilogx(freq,p);grid

Best Answer

Related Solutions

MATLAB: Hamming window matlab code

MATLAB: Designing IIR Filters using Bilinear Transform

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