%
%%
% Sample and hold: esempio
%

clear all, close all, clc
 
%% Problema

Vm1=20;                     % Voltage magnitude for v1
Vm2=10;                     % Voltage magnitude for v2

DOB=27;                     % Random parameter #1
MOB=11;                     % Random parameter #2

f1=MOB*10;                  % Frequency for v1
f2=DOB*10;                  % Frequency for v2
w1=2*pi*f1;                 % Frequency for v1 (rad/sec)
w2=2*pi*f2;                 % Frequency for v2 (rad/sec)

%0.04;                      % Simulation time

t=0:0.00005:0.04;           % Time for plotting signal
v1=Vm1*sin(w1*t);           % v1 
v2=Vm2*sin(w2*t);           % v2
v=v1+v2;                    % Combination
 
figure, subplot(211), plot(t,v,'r')
xlabel('Tempo (s)'), ylabel('v(t)')
title('Segnale da campionare')
 
%% Defining sampling periods 
fm=max(f1,f2);          % Maximum frequency component
fs1=2*fm; Ts1=1/fs1;    % Just same
fs2=3*fm; Ts2=1/fs2;    % fs>2fm (satisfying sampling theorem)
fs3=1*fm; Ts3=1/fs3;    % fs<2fm (not satisfying sampling theorem)
 
%% fs>2fm (satisfying sampling theorem)
ts2=0:Ts2:0.04;
v1s2=Vm1*sin(w1*ts2); 
v2s2=Vm2*sin(w2*ts2);
vs2=v1s2+v2s2;
subplot(212), stem(ts2,vs2,':')
xlabel('Tempo (s)'), ylabel('v(k)')
title('Segnale campionato')
 
%% Segnali sovrapposti
figure, plot(t,v,'r'), hold on
stem(ts2,vs2,':b')
xlabel('Tempo (s)'), ylabel('v(t) e v_k')
title('Segnale da campionare v(t) e campioni v_k')
legend('Segnale da campionare','campioni')
 
%% Comparison of signals (by plotting zoh type signals)
figure
subplot(211), stem(ts2,vs2,':')
xlabel('Tempo (s)'), ylabel('v(k)')
title('Segnale campionato')

subplot(212), stem(ts2,vs2,':'), hold on
stairs(ts2,vs2,'r')
xlabel('Tempo (s)'), ylabel('v_r(t)')
title('Segnale in uscita da ZOH')
legend('Campioni','Segnale da ZOH')