clear;
N=99;
m=(N-1)/2;
k=0:N-1;
h1=(1/2)*sinc((k-m)/2);
num1=h1;
den1=[1, zeros(1,N-1)];
k=-pi:pi/100:pi;
H1=freqz(num1,den1,k);
mag1=abs(H1);
phase1=180/pi*unwrap(angle(H1));
for i=1:N
k=i-1;
h2(i)=(1/2)*sinc((k-m)/2)*(0.54+0.46*cos(pi*(k-m)/m));
end
num2=h2;
den2=[1, zeros(1,N-1)];
k=-pi:pi/100:pi;
H2=freqz(num2,den2,k);
mag2=abs(H2);
phase2=180/pi*unwrap(angle(H2));
subplot(2,1,1);
plot(k,mag1,k,mag2);grid;
subplot(2,1,2);
plot(k,phase1,k,phase2);grid
