%  ex_01_11_1.m :  習(xí)題 1.11


clear all;
close all;
A = 220;
f = 50;
fs = 200;
Ts=1/fs;
w = 2*pi*f*Ts;
n =0:31;
y = A*sin(w*n);
subplot(211);stem(n,y,'.');

fs = 800;
Ts=1/fs;
w = 2*pi*f*Ts;
n =0:31;
y = A*sin(w*n);
subplot(212);stem(n,y,'.');

f0 = 5;
fs = 200;
Ts=1/fs;
w = 2*pi*f0*Ts;
n=0:39;
y=0.54-0.46*cos(w*n);
figure;
subplot(211);stem(y,'.')

f0 = 10;
fs = 200;Ts=1/fs;
n=-40:40;
w = 2*f0*Ts*n;
y=sinc(w);
subplot(212);stem(n,y,'.');