%lineáris fázisú szűrő a 'hangszur'-hoz
f=[0 .7 .8 1];
m=[1 1  0  0];
a=1;
[b]=fir1(60,.7);
%[b]=firpm(60,f,m);
[H,w]=freqz(b,a);
figure(1)
%plot(w/pi,abs(H))
plot(w/pi,20*log10(abs(H)+eps))
grid on
figure(2)
plot(w/pi,unwrap(angle(H)))
%plot(w/pi,20*log10(abs(H)+eps))
grid on