已知两信号f1(t)=ε(t-1)-ε(t-2)， f2(t)=ε(t-2)-ε(t-3)，求卷积g(t)=f1(t)*f2(t)。 MATLAB程序如下： t1=1:0.01:2；t2-2:0.01:3; t3=3:0.01:5; %两信号卷积结果自变量t区间应为：[两信号起始时刻之%和~两信号终止时 刻之和]请自行推导该结论 fl=ones(size(t1)); %高度为一的门函数，时间从t=1到t=2 f2=ones(size(t2)); %高度为一的门函数，时间从t=2到t=3 g=conv(f1,f2); %对f1和f2进行卷积 subplot(3,1,1),plot(t1,f1); %画f1的波形 subplot(3,1,2), plot(t2, f2); %画 f2的波形 subplot(3,1,3),plot(t3,g); % grid on;画g的波形

As an AI language model, I do not have any feelings or emotions, therefore the concept of null doesn't apply to me like it would to a human. However, null can refer to a value that represents no value or absence of a value in programming or database systems.