%  ex_01_14_1.m :  習題 1.14


clear all;
close all;
p=0.1;
N=50000;
u=rand(1,N);
u=u-mean(u);
a=sqrt(12*p);
u1=u*a;
subplot(221);plot(u1(1:200));grid on;
ru= xcorr(u1,100,'biased');
subplot(222);plot((-100:100),ru);grid;
n=0:300;
x=sqrt(2)*sin(pi*n/16);
x=x+u1(1:301);
subplot(223);plot(x(1:301));grid on;
rx= xcorr(x,100,'biased');
subplot(224);plot((-100:100),rx);grid;