cps lab6 zad1

clear variables; close all;

butt = load('butter.mat');
z = butt.z; p = butt.p; k = butt.k;
fd = 1189; fg = 1229; fs = 16e3;
% f = (fd:1/fs:fg)
f = (1100:1/fs:1300);
w = f.*(2*pi);

Hs = analog(w, z, p, k);

[zd,pd,kd] = bilinear(z,p,k,fs);
[bd, ad] = zp2tf(zd, pd, kd);
Hz = freqz(bd, ad, f, fs);

figure;
plot(f, 20*log10(abs(Hs)), f, 20*log10(abs(Hz)), f, -3*ones(1, length(f)), '--g'); grid;

f1 = 1209; f2 = 1272;
t = 1/fs:1/fs:1;
x = sin(2*pi*t*f1) + sin(2*pi*t*f1);

X = fft(x);
% Y = X.*Hs;
% y = ifft(Y);

y = filter(bd, ad, x);

figure;
plot(t, x, t, y);