ms3r4.m

《数字信号处理实验(MATLAB版)》这

n1=-4:-1;x1=2*n1+5;
n2=0:4;x2=6;
n=min([n1,n2]):max([n1,n2]);  %为x信号建立时间序列n
N=length(n);                      %求时间序列n的点数N
y1=zeros(1,N);                    %新建一维N列的y1全0数组
y2=zeros(1,N);                    %新建一维N列的y2全0数组
y1(find((n>=min(n1))&(n<=max(n1))))=x1;  %为y1赋值
y2(find((n>=min(n2))&(n<=max(n2))))=x2;  %为y2赋值
x=y1+y2;                      %建立x信号
subplot(2,2,1),stem(n,x,'filled'),grid;    
title('x(n)');
axis([-7,7,1.1*min(x),1.1*max(x)]);

n3=n+2;
x3=2*x;
subplot(2,2,2),stem(n3,x3,'filled'),grid;   
title('2x(n-2)');
axis([-7,7,1.1*min(x3),1.1*max(x3)]);

n3=n-2;
x3=2*x;
subplot(2,2,3),stem(n3,x3,'filled'),grid;   
title('2x(n+2)');
axis([-7,7,1.1*min(x3),1.1*max(x3)]);

n3=-fliplr(n+2);
x3=fliplr(x);
subplot(2,2,4),stem(n3,x3,'filled'),grid; 
title('x(2-n)');
axis([-7,7,1.1*min(x3),1.1*max(x3)]);