## FIR - BSF - Window Based

March 22, 2011 Coded in Scilab

Scilab PROGRAM TO DESIGN AND OBTAIN THE FREQUENCY RESPONSE OF FIR FILTER
Band Stop FILTER (or)Band Reject Filter - Window Based

``````//PROGRAM TO DESIGN AND OBTAIN THE FREQUENCY RESPONSE OF FIR FILTER
//Band Stop FILTER (or)Band Reject Filter
clear all;
clc;
close;
M = 7             //Filter length = 11
Wc = [%pi/5,3*%pi/4];        //Digital Cutoff frequency
Wc2 = Wc(2)
Wc1 = Wc(1)
Tuo = (M-1)/2     //Center Value
hd = zeros(1,M);
W = zeros(1,M);
for n = 1:M
if (n == Tuo+1)
hd(n) = 1-((Wc2-Wc1)/%pi);
else    hd(n)=(sin(%pi*((n-1)-Tuo))-sin(Wc2*((n-1)-Tuo))+sin(Wc1*((n-1)-Tuo)))/(((n-1)-Tuo)*%pi);
end
if(abs(hd(n))<(0.00001))
hd(n)=0;
end
end
hd
//Rectangular Window
for n = 1:M
W(n) = 1;
end
//Windowing Fitler Coefficients
h = hd.*W;
disp(h,'Filter Coefficients are')
[hzm,fr]=frmag(h,256);
hzm_dB = 20*log10(hzm)./max(hzm);
plot(2*fr,hzm_dB)
xlabel('Normalized Digital Frequency W');
ylabel('Magnitude in dB');
title('Frequency Response 0f FIR BPF using Rectangular window M=7')
xgrid(1)``````