clf;
clear all;

n = -30:1:30;
w = -300:0.01:300;

x = exp(-3*n).*heaviside(n);
h = exp(-2*n).*heaviside(n);

%x = zeros(size(t));
%h = zeros(size(t));

%x = (t.^2).*exp(-1.*t.^2).*(cos(t.^2).^2);
%h = exp(-0.2*t.^2).*sin(t.^2).*heaviside(t);

% for iter = 1:length(t)
%    x(iter) = t(iter)^2*exp(-1.*t(iter)^2)*cos(t(iter)^2)^2;
%    h(iter) = exp(-0.2*t(iter)^2)*sin(t(iter)^2)*heaviside(t(iter));
% end

X = zeros(size(w));
H = zeros(size(w));

for iter = 1:length(w)
    X(iter) = sum(x.*exp(-1j*w(iter)*n)); %Fourier Transform
    H(iter) = sum(h.*exp(-1j*w(iter)*n));
end

Y = X.*H;
y = zeros(size(n));

for iter = 1:length(n)
   y(iter) = trapz(w, Y.*exp(1j*w*n(iter)))/(2*pi);
end

%x_exact = exp(-3*t0)*heaviside(t0);
%h_exact = exp(-2*t0)*heaviside(t0);

%X_exact = fourier(x_exact, t0);
%H_exact = fourier(h_exact, t0);

%Y_exact = H_exact*X_exact;

y_exact = conv2(x, h);
n2 =n(1)+n(1):1:n(end)+n(end);

figure(1);
plot(n2, y_exact, n, abs(y));
legend('Exact', 'Approximate');
title('Exact and approximate y(t)');
axis([-5 5 -.02 1.2]);