% ctft
clear,close all,
dt = 0.01;dw = 0.1;
t = -2:dt:2;
w = -8*pi:dw:8*pi;
x = u(t+1)-u(t-1);
X = x*exp(-j*w'*t)'*dt;
subplot(221)
plot(t,x)

subplot(222)
plot(w,abs(X))
title('Magnitude spectrum of x(t)')
axis([-8*pi,8*pi,0,2])
subplot(224)
plot(w,angle(X))
axis([-8*pi,8*pi,-pi,pi])