%  ex_03_13_1.m :  習題 3.13

clear all;
close all;

h(1)=1;h(2)=0.5;h(2)=0,25;
for n=0:50;      
    x(n+1)=n/5;
end;
for n=51:99;
    x(n+1)=20-n/5;
end
N=100;
L=20; 
M=length(h);
y=zeros(1,N+M-1);
tempy=zeros(1,M+L-1);
tempx=zeros(1,L);
for k=0:N/L-1
      tempx(1:L)=x(k*L+1:(k+1)*L);
      tempy=conv(tempx,h);
      y=y+[zeros(1,k*L),tempy,zeros(1,N-(k+1)*L)];
end
subplot(211);stem(x,'.'); 
subplot(212);stem(y,'.');