Лаба1 / LR1

close all;

U1 = 9;
U2 = -3;
U3 = -8;
U4 = 5;
T1 = 3;
T2 = 6;
Fd = 5;
T = 1 / Fd;

%1
t1 = 0:T:T1;
t2 = T1+T:T:T2;
t = 0:T:T2;
u1 = U1 + (U2-U1)/T1*t1;
u2 = U3 + (U4-U3)/(T2-T1)*(t2-T1);
u = [u1 u2];
figure;
hold on;
plot(t,u);
stem(t,u);
xlabel('t, ms');
ylabel('U, V');

%2
N = length(u);
k = (0:N-1).';
W = pi/500;
w = -pi:W:pi;
kw = k*w;
kw = kw*(-1i);
e = exp(kw);
Sp = u*e;
f = Fd*w/(2*pi);
figure;
subplot(2,1,1);
ASp = abs(Sp);
plot(f,ASp);
title('Magnitude Spectrum');
xlabel('f, kHz');
ylabel('|A(f)|');
subplot(2,1,2);
FSp = angle(Sp);
plot(f,FSp);
title('Phase Spectrum');
xlabel('f, kHz');
ylabel('arg(A(f))');

%3
td = (-5*T):(T/10):(T2+5*T);
Sr = zeros(1,length(td));
for i= 1:N
Sr = Sr + u(i).*sinc((td-(i-1).*T)./T);
end
figure;
hold on;
grid on;
plot(td,Sr);
stem(t,u);
xlabel('t, ms');
ylabel('Sr, V');