% Name: aliasing.m
%
clear,close all,
t=-10:0.01:10;
a=2*pi/3;

w=pi;
ws=2*w;
Ts=2*pi/ws;
n=-10/Ts:10/Ts;
x=cos(pi*t+a);
x1=cos(a)*cos(pi*t);
xn=cos(pi*n*Ts+a);
subplot(211)
plot(t,x,'r'),hold on,axis([-10,10,-1.2,1.2]),plot(t,x1,'b')
title('The reconstruction of signal x(t)')
%subplot(223)
stem(n,xn,'k.'),
axis([-10,10,-1.2,1.2])
xlabel('Time t')