离散线性时不变系统分析报告

1 / 6 1.设某LTI 系统的]5[][nnh，输入]5[][][nununx，求系统输出][*][][nhnxny: 主程序如下：n=[-5:20];h=delta(n-5);x=stepseq(0,-5,20)-stepseq(5,-5,20);[y,ny]=conv_m(x,n,h,n);subplot(2,2,1);stem(n,x);title('x[n]');xlabel('n');axis([-5 20 0 1.2]);grid on;subplot(2,2,2);stem(n,h);title('h[n]');xlabel('n');axis([-5 20 0 1.2]);grid on;subplot(2,2,3);stem(ny,y);title('y[n]');xlabel('n');axis([-5 20 0 1.2]);grid on;Stepseq.m 的源程序如下：function [x,n]=stepseq(n0,n1,n2);if nargin ~=3 disp('Usage:Y=stepseq(n0,n1,n2)');elseif((n0n2)|(n1>n2)) error('arguments must satisfy n1<=n0<=2')endn=[n1:n2];x=[(n-n0)>=0]; conv_m.m的源程序如下：function[y,ny]=conv_m(x,nx,h,nh)if nargin~=4 disp('Usage:Y=conv_m(x,nx,h,nh)');return;end;nyb=nx(1)+nh(1);nye=nx(length(x))+nh(length(h));ny=[nyb:nye];y=conv(x,h); 思考题：若][*][][0nnnxny, 试写出][ ny与][nx的关系，并对 MATLAB的仿真结果。解：因为0nn函数是延时器， 所以y[n]=x[n]* 0nn=x[ n -0n ] 。2 / 6 2. 设某线性时不变系统的h[n]=其它05n0n输入信号为 x[n]=其它05n01求输出： a ：];[*][][1nhnxnyb：]5[*][][2nhnxny（1）主程序如下：n=[-5:20];u1=stepseq(0,-5,20);u2=stepseq(6,-5,20);x=u1-u2;h=n.*x;subplot(3,1,1);stem(n,x);axis([-5 20 0 2]);title('Input Sequence');ylabel('x[n]');subplot(3,1,2);stem(n,h);axis([-5 20 0 6]);title('Inpulse Response');ylabel('h[n]');[y1,ny]=conv_m(x,n,h,n);subplot(3,1,3);stem(ny,y1);title('Output Sequence');xlabel('n' );ylabel('y_1[n]');Stepseq.m 的源程序如下：3 / 6 function [x,n]=stepseq(n0,n1,n2);if nargin ~=3 disp('Usage:Y=stepseq(n0,n1,n2)');elseif((n0n2)|(n1>n2)) error('arguments must satisfy n1<=n0<=2')endn=[n1:n2];x=[(n-n0)>=0]; conv_m.m的源程序如下：function[y,cy]=conv_m(x,nx,h,nh)if nargin~=4 disp('Usage:Y=conv_m(x,nx,h,nh)');return;end;nyb=nx(1)+nh(1);nye=nx(length(x))+nh(length(x));ny=[nyb:nye];y=conv(x,h);（2）主程序如下：n=-10:20;u1=stepseq(0,-10,20);u2=stepseq(6,-10,20);x=u1-u2;u3=stepseq(-5,-10,20);u4=stepseq(1,-10,20);x1=u3-u4;h...