I need help with plotting

I can't get it to plot this. I don't know how to write this in matlab up=u1*(t>=0)*(y<=tpulssi)+u2*(t>=tpr*2)*(t<=tpr*2+tpulssi); I need it to plot it like this:

clear
close all
syms t
Zc=300;
R=100;
s=100;
v=300/(1*10^-6)
tpulssi=s/v
k=-1000/tpulssi

p=(R-Zc)/(R+Zc)
s2=25
tpr=s2/v

%heijastuva

t=0:0.001*10^-6:1*10^-6;
u1=k*t+abs(k)*tpulssi;
u2=p*k*t-abs(p*k*(2*tpr+tpulssi));

up=u1*(t>=0)*(y<=tpulssi)+u2*(t>=tpr*2)*(t<=tpr*2+tpulssi);

figure(1)
plot(t,up);
hold on
plot(t,u2)
hold on
plot(t,up)
hold off

Answer 1

[Chunru]

syms t
Zc=300;
R=100;
s=100;
v=300/(1*10^-6)

v = 300000000

tpulssi=s/v

tpulssi = 3.3333e-07

k=-1000/tpulssi

k = -3.0000e+09

p=(R-Zc)/(R+Zc)

p = -0.5000

s2=25

s2 = 25

tpr=s2/v

tpr = 8.3333e-08

%heijastuva
t=0:0.001*10^-6:1*10^-6;
u1=k*t+abs(k)*tpulssi;
u2=p*k*t-abs(p*k*(2*tpr+tpulssi));
% need the .* (or array operation)
up=u1.*(t>=0).*(t<=tpulssi)+u2.*(t>=tpr*2).*(t<=tpr*2+tpulssi);
figure(1)
plot(t,u1, 'DisplayName', 'u1')
hold on
plot(t,u2,  'DisplayName', 'u2')
hold on
plot(t,up, 'k', 'LineWidth', 2, 'DisplayName', 'up');
legend
grid on
hold off

[Dani German]

Awesome answer, thanks for the help.