%% Simulation / Modélisation d'un système de photodétection
%   Module : Ingénierie Electronique 
%       pour le Traitement de l'Information
%--------------------------------------------------------------
%   TD_10 : Photodétection - Modélisation / Correction TD
%--------------------------------------------------------------
%   Auteur : Julien VILLEMEJANE
%   Date : 27/08/2020
%--------------------------------------------------------------
clear all;
close all;
%% Constantes
RT = 1e5;           % resistance de contre-reaction
Cphd1 = 75e-12;      % capacité de la photodiode
Cphd2 = 10e-12;      % capacité de la photodiode
wc1 = 1/(RT*Cphd1)   % pulsation de coupure RT Cphd
wc2 = 1/(RT*Cphd2)   % pulsation de coupure RT Cphd
fc1 = wc1/(2*pi)
fc2 = wc2/(2*pi)
A0 = 2e5;
wGBP = 2*pi*3e6;

wT1 = sqrt(wc1*wGBP)
fT1 = wT1 / 2 / pi
mT1 = sqrt(wc1/wGBP)*0.5

wT2 = sqrt(wc2*wGBP)
fT2 = wT2 / 2 / pi
mT2 = sqrt(wc2/wGBP)*0.5

f = logspace(2,8,1001);
w = 2*pi.*f;
t = linspace(0, 0.00002, 1001);

%% Systèmes
sys1 = tf([RT],[(1/wT1)*(1/wT1) 2*mT1/wT1 1]);
[mag1, phase1, wo1] = bode(sys1, w);
sys2 = tf([RT],[(1/wT2)*(1/wT2) 2*mT2/wT2 1]);
[mag2, phase2, wo2] = bode(sys2, w);
figure;
subplot(2,1,1);
semilogx(f, 20*log10(squeeze(mag1)), f, 20*log10(squeeze(mag2)));
xlabel('Frequence (Hz)'); ylabel('Gain (dB)');
legend('Système 1','Système 2');
grid on;
subplot(2,1,2);
semilogx(f, squeeze(phase1), f, squeeze(phase2));
ylabel('Phase (deg)');
grid on;
figure;
subplot(2,1,1);
semilogx(f, 20*log10(squeeze(mag1)), f, 20*log10(squeeze(mag2)));
xlabel('Frequence (Hz)'); ylabel('Gain (dB)');
legend('Cphd = 75pF','Cphd = 10pF');
grid on;
subplot(2,1,2);
semilogx(f, squeeze(phase1), f, squeeze(phase2));
ylabel('Phase (deg)');
grid on;

% step
[y1, t1] = step(sys1,t);
[y2, t1] = step(sys2,t);
figure;
subplot(2,1,1);
plot(t, y2); grid on; xlabel('Temps (s)');
title('Systeme A');
subplot(2,1,2);
plot(t, y1); grid on; xlabel('Temps (s)');
title('Systeme B');