ex_2.m

信号与系统分析以matlab实现

%ex_2
clear all;
x=[1 2 3 4 5 6 7 6 5 4 3 2 1];
n=[-4 -3 -2 -1 0 1 2 3 4 5 6 7 8];
%
[x1_1,n1_1]=sigshift(2*x,n,5);%2x(n-5)
[x1_2,n1_2]=sigshift(-3*x,n,-4);%-3x(n+4)
[x1,n1]=sigadd(x1_1,n1_1,x1_2,n1_2);%2x(n-5)-3x(n+4)
%
[x2_1,n2_1]=sigshift(x,n,-3);%x(n+3)
[x2_2,n2_2]=sigfold(x2_1,n2_1);%x(-n+3)
[x2_3,n2_3]=sigshift(x,n,2);%x(n-2)
[x2_4,n2_4]=sigmult(x,n,x2_3,n2_3);%x(n)x(n-2)
[x2,n2]=sigadd(x2_4,n2_4,x2_2,n2_2);%x(n)x(n-2)+x(-n+3)
%
x3_2=zeros(1,length(x));
n3_2=n;
    for j=1:5
        [x3_1,n3_1]=sigshift(x,n,j)
        [x3_2,n3_2]=sigadd(x3_2,n3_2,x3_1,n3_1)
    end
x3=x3_2.*n3_2
n3=n3_2