数字信号处理实验指导书 n=min(min(n1).min(n2)):max(max(n1).max(n2)) yl=zeros(1,length(n)),y2=y1; yl(find((n>=min(n1))&(n<=max(n1))==1))=x1; y2(find((n>=min(n2)&(n<=max(n2))-=1))=x2; y=yl+y2; 例题： x1=1,2,3,41x2=[1,2,3,4,5] nl=-2:1,n2=04 sigadd(x1.n1.x2.n2) 4、两个信号相乘的生成函数sigmult.m function [y.n]=sigmult(x1.n1.x2.n2) n=min(min(n1),min(n2)):max(max(n1),max(n2)) yl=zeros(1,length(n));y2=y1; yl(find((n>=min(n1)&(n<=max(n1))==1))=x1; y2(find((n>=min(n2)&(n<=max(n2))==1))=x2; y=yl.'y2. 例题： x1=1,2,3,41x2=[1,2,3,4,5] nl=0:3,n2-04 n=min(min(n1),min(n2)):max(max(n1),max(n2)) sigmult(x1,n1,x2,n2) stem(n,sigmult(xI,nl,x2.n2)) 5、序列移位m)=x(n-)的生成函数sigshift.m function [y,n]=sigshift(x,m,n0) n=m+n0;y=x %已知x=[1,2,3,4,5,6,5,4,3,2,1] %求x(n)=2xm-53xn-4)的波形数字信 号 处 理 实 验 指 导 书 6 n=min(min(n1),min(n2)):max(max(n1),max(n2)) y1=zeros(1,length(n)); y2=y1; y1(find((n>=min(n1))&(n<=max(n1))==1))=x1; y2(find((n>=min(n2))&(n<=max(n2))==1))=x2; y=y1+y2; 例题： x1=[1,2,3,4]; x2=[1,2,3,4,5] n1=-2:1; n2=0:4 sigadd(x1,n1,x2,n2) 4、两个信号相乘的生成函数 sigmult.m function [y,n]=sigmult(x1,n1,x2,n2) n=min(min(n1),min(n2)):max(max(n1),max(n2)) y1=zeros(1,length(n)); y2=y1; y1(find((n>=min(n1))&(n<=max(n1))==1))=x1; y2(find((n>=min(n2))&(n<=max(n2))==1))=x2; y=y1.*y2; 例题： x1=[1,2,3,4]; x2=[1,2,3,4,5] n1=0:3; n2=0:4 n=min(min(n1),min(n2)):max(max(n1),max(n2)); sigmult(x1,n1,x2,n2) stem(n,sigmult(x1,n1,x2,n2)) 5、序列移位 0 y n x n n ( ) ( ) = − 的生成函数 sigshift.m function [y,n]=sigshift(x,m,n0) n=m+n0; y=x %已知 x(n)=[1,2,3,4,5,6,5,4,3,2,1] %求 x1(n)=2x(n-5)-3x(n-4)的波形