%exm051332_1.m
M=5;																	%<1>
tend=1;
T=10;																	%<3>
N=2^M;
dt=T/N;
n=0:N-1;
t=n*dt;
w=zeros(size(t,2),1);
Tow=find((tend-t)>0);
w(Tow,1)=ones(length(Tow),1);
shg,plot(t,w,'b','LineWidth',2.5),title('Time Waveform');xlabel('t --- >')
%
disp('按任意鍵，繼續(xù)！'),pause 
[AW,f]=cftbyfft(w,t,0);
ff=f+eps;
AWW=abs(sin(pi*ff)./(pi*ff));
shg
plot(f,AW,'b-',ff,AWW,'r:')
title('Aliasing caused by undersampling')
xlabel('f --- >');ylabel('|W(f)|'),legend('by FFT','Theoretical')