Time Interval x(t)·h(t-0) Output t< 0 y(1)=0 t+I 1<t< y()=(t+2)t+2-1 1t+2 (t+1) <t< =÷11= 1<t<2 y()=-(+2-3t-1) -是(t t>2 yt)=0-1 -1 0 0 1 1 2 2