% general settings, which can be changed
L = 1; %length of transmission, in [m]
Zc = 100; %transmission's impedance, in [ohm]
vp = 3e8; %transmission's waves' speed, in [m/s]
RG = 140; %source's impedance, in [ohm]
RL = 150; %end of transmission's impedance, in [ohm]
gammaL = (RL-Zc)/(RL+Zc);
gammaG = (RG-Zc)/(RG+Zc);

 %amount of time the simulation runs, in [s]

%i have also used the vg function  to create the cos source.
%b.
%creating time vector
I_idodim=zeros(4,1000);
V_idodim=zeros(4,1000);
Iss_Mat=zeros(4,1000);
Vss_Mat=zeros(4,1000);
Time_Mat=zeros(4,1000);
Time_Mat(1,:)=linspace(0,10*L/vp,1000);
Time_Mat(2,:)=linspace(0,L/vp,1000);
Time_Mat(3,:)=linspace(3*L/vp,4*L/vp,1000);
Time_Mat(4,:)=linspace(9*L/vp,10*L/vp,1000);
Z = L/2;
%V = zeros(1,1000);
%I = zeros(1,1000);
for p=1:4
    V_temp = zeros(1,1000);
    I_temp = zeros(1,1000);
for k = 0:4
    V_temp = (power(gammaG,k)*power(gammaL,k)).*(Zc/(Zc+RG)).*vg(Time_Mat(p,:)-(2*k*(L/vp))-(Z/vp))+ ...
        (power(gammaG,k)*power(gammaL,k+1))*(Zc/(Zc+RG)).*vg(Time_Mat(p,:)-(2*(k+1)*(L/vp))+(Z/vp));
    I_temp = (1/Zc)*(power(gammaG,k)*power(gammaL,k)).*(Zc/(Zc+RG)).*vg(Time_Mat(p,:)-(2*k*(L/vp))-(Z/vp))- ...
        (1/Zc)*(power(gammaG,k)*power(gammaL,k+1))*(Zc/(Zc+RG)).*vg(Time_Mat(p,:)-(2*(k+1)*(L/vp))+(Z/vp));
    V_idodim(p,:) = V_idodim(p,:) + V_temp;
    I_idodim(p,:)=I_idodim(p,:)+I_temp;
end
end
for p=1:4
Vss_Mat(p,:) = -0.19.*cos(6.28e9.*Time_Mat(p,:)-20.94.*Z)+0.35.*sin(6.28e9.*Time_Mat(p,:)-20.94.*Z)-0.038.*cos(6.28e9.*Time_Mat(p,:)+20.94.*Z)+0.07.*sin(6.28e9.*Time_Mat(p,:)+20.94.*Z);
Iss_Mat(p,:)=Vss_Mat(p,:)/Zc;
end
figure(1)
plot(Time_Mat(1,:),V_idodim(1,:),'color','b');
title('V Echo Series(t,-L/2) when 0<t<10T');
xlabel('t[s]');
ylabel('V[v]');
figure(2)
plot(Time_Mat(1,:),I_idodim(1,:),'color','r');
title('I Echo Series(t,-L/2) when 0<t<10T');
xlabel('t[s]');
ylabel('I[A]');
figure(3)
plot(Time_Mat(1,:),Vss_Mat(1,:),'color','b');
title('V Steady State(t,-L/2) when 0<t<10T');
xlabel('t[s]');
ylabel('V[v]');
figure(4)
plot(Time_Mat(1,:),Iss_Mat(1,:),'color','r');
title('I Steady State(t,-L/2) when 0<t<10T');
xlabel('t[s]');
ylabel('I[A]');
figure(5)
plot(Time_Mat(2,:),V_idodim(2,:),'color','b');
hold on;
plot(Time_Mat(2,:),Vss_Mat(2,:),'color','r');
title('V(t,-L/2) when 0<t<T');
xlabel('t[s]');
ylabel('V[v]');
legend('V Echo Series','V Steady state')
figure(6)
plot(Time_Mat(3,:),V_idodim(3,:),'color','b');
hold on;
plot(Time_Mat(3,:),Vss_Mat(3,:),'color','r');
title('V(t,-L/2) when 3T<t<4T');
xlabel('t[s]');
ylabel('V[v]');
legend('V Echo Series','V Steady state')
figure(7)
plot(Time_Mat(4,:),V_idodim(4,:),'color','b');
hold on;
plot(Time_Mat(4,:),Vss_Mat(4,:),'color','r');
title('V(t,-L/2) when 9T<t<10T');
xlabel('t[s]');
ylabel('V[v]');
legend('V Echo Series','V Steady state')

function y = vg(t)
    f=1e9;
    omega = 2*pi*f;
    y = sin(omega*t).*heaviside(t);
end