%priklady na DTFS, signaly na intervale
clear all;
close all;
axis equal
subplot(5,1,1)

Tsig=10;
%Tsig=4;


A=3;
Tbox=1;
plot_points=100;
tn=0:Tsig/plot_points:Tsig;
syms ts;
mysig_n=zeros(1,plot_points+1);
mysig_n(1:Tbox/Tsig*plot_points)=A;
mysig_s=A
plot(tn,mysig_n);
grid on;

N=10
n=-N:N;
product=mysig_s*exp(-i*n*2*pi/Tsig*ts)
cn=1/Tsig*eval(int(product,ts,0,Tbox));
subplot(5,1,2);
%stem(n,abs(cn))
stem(n/Tsig,abs(cn))
grid on;
subplot(5,1,3);
stem(n/Tsig,angle(cn))
grid on;

recon=zeros(1,plot_points+1);
actsig=cn(N+1)
recon= recon + actsig;
subplot(5,1,4); plot(tn,recon); hold on;

for idx=1:N
    actsig=cn(N+1-idx)*exp(i*-idx*2*pi/Tsig*tn) + cn(N+1+idx)*exp(i*idx*2*pi/Tsig*tn)
    subplot(5,1,4); plot(tn,actsig); hold on;
    recon= recon + actsig;    
end
grid on
subplot(5,1,5);
plot(tn,recon)
grid on