N=[1,0,0]
D=[75.579367, -137.90481, 63.325442]
T=2e-6
f=linspace(0,3e4,200);
H=freqz(N,D,f,1/T);
figure(1)
plot(f,abs(H));
grid
xlabel f
ylabel '|H|'
title 'Modulová charakteristika'
figure(2)
plot(f,phase(H));
grid
xlabel f
ylabel 'PH'
title 'Fázová charakteristika'
t=diff(-phase(H))./diff(w);
figure(3)
plot(f(1:199),t);
grid
xlabel f
ylabel 't'
title 'Skupinové zpoždìní'
