北理工信号与系统2 - 图文

x1(t)?x2(t)?xx(?2)1(?2)1(t)?x(?2)1(?2)1(?2)2(t)(t)?x(?2)2(t)?x(t)?[?(t)?2?(t?1)??(t?2)](t)?2x(?2)12?xx(?2)12(t?1)?x(?2)1(t?2)(t)?1/2tu(t)?1/2(t?1)u(t?1)见下图

x1(t)x2(t)11(?1)x1(t)1t(1)x2(t)12t1t

-1

t(?2)x1(t)(2)x2(t)(1)

1x1(t)?x2(t)t1

2t

(-2)

123t

解：f(t)?2?(t?1)?2?(t?7)f(t)?1/2(t?2)u(t?2)?1/2(t?5)u(t?5)(1)2(1)1?f1(t)?f2(t)?f(t)?f(1)1(?1)2(t)?2[?(t?1)??(t?7)]?1/2[(t?2)u(t?2)?(t?5)u(t?5)]?(t?1?2)u(t?3)?(t?1?5)u(t?1?5)?(t?2?7)u(t?2?7)?(t?5?7)u(t?5?7)?(t?3)u(t?3)?(t?6)u(t?6)?(t?9)u(t?9)?t?12)u(t?12)