clc, clear, close all

[x, Fs1] = audioread('whitenoise2018.wav');
[y, Fs2] = audioread('whitenoise_rec2018.wav');

dt = 10/length(x);
T = 10;
t = 0:dt:T-dt;
fs = Fs1;



X = fft(x);
Y = fft(y);

Rxx = xcorr(x,x);
Rxy = xcorr(x,y);

subplot(2,1,1);
plot((-length(Rxx)/2 : length(Rxx)/2-1)/fs*1000, Rxx)   %s->ms
axis tight;
xlabel('time [ms]');
ylabel('Rxx');
title('Autokorelacja Rxx');
grid on;

subplot(2,1,2);
plot((-length(Rxy)/2 : length(Rxy)/2-1)/fs*1000, Rxy)   %s->ms
axis tight;
xlabel('czas [ms]');
ylabel('Rxy');
title('Korelacja krzyżowa Rxy');
grid on;

figure();
H = Y./X;
N = length(H);
absH = abs(H);
argH = unwrap(angle(H));
f=(0:length(absH)/2-1)*fs/(length(absH));

subplot(2,1,1);
semilogx(f,20*log((absH(1:N/2))));
axis tight;
xlabel('częstotliowość [Hz]');
ylabel('|L|');
line([fs/2 fs/2], ylim,'Color',[1 0 0],'LineWidth',1);
title('Ch-ka amplitudowo-częstotliwościowa');
grid on;

subplot(2,1,2);
semilogx(f,(argH(1:N/2)));
axis tight;
xlabel('częstotliowość [Hz]');
ylabel('faza [ ^o]');
line([fs/2 fs/2], ylim,'Color',[1 0 0],'LineWidth',1);
title('Ch-ka fazowowo-częstotliwościowa');
grid on;

figure();
h = ifft(H);
plot(t(1:1500),h(1:1500));
axis tight;
xlabel('czas [s]');
ylabel('A');
title('Odpowiedź impulsowa');
grid on;

peak = 0.1;
for i=1:length(h)
    if h(i) >= peak
        distance = i/fs*320;
        break;
    end
end