q1.m

1、 假定有一目标沿水平方向运动

clear all
figure(1)
a=0.1;
k=50;
n=100:200;
x(n)=cos(0.3*pi*n)+0.5*cos(0.6*pi*n);
y(n)=x(n)+a*x(n-k);
stem(n,y(100:200));

figure(2)
t=-199:199;
R=xcorr(y);
stem(t,R);

figure(3)    %k变化(k=40:5:60)，a不变(a=0.1)
clear y(n)
hold on
k=40:5:60;
d=['r' 'g' 'b' 'c' 'm'];
for e=1:length(k)
y(n)=x(n)+a*x(n-k(e));
R=xcorr(y);
stem(t,R,d(e));
end

figure(4)    %k变化(k=0:1:60)，a不变(a=0.1)的R(0)
hold on
clear y(n)
k=0:1:60;
for e=1:length(k)
y(n)=x(n)+a*x(n-k(e));
R=xcorr(y);
stem(k(e),max(R));
end

figure(5) %a变化(a=0:0.05:0.2) k不变(k=50)
clear y(n)
hold on
k=50;
a=0:0.05:0.2;
for e=1:length(a)
y(n)=x(n)+a(e)*x(n-k);
R=xcorr(y);
stem(t,R,d(e));
end

figure(6) %a变化(a=0:0.01:0.2) k不变(k=50)的R（0）
hold on
a=0:0.01:0.2;
for e=1:length(a)
y(n)=x(n)+a(e)*x(n-k);
R=xcorr(y);
stem(a(e),max(R));
end