3常用信号的拉氏变换 u S u(ta s-ta n δ(t) 6(t-t0) S3.常用信号的拉氏变换 S 1 t u t a − ( ) s + a 1 n t 1 ! n+ s n  (t) 1 ( ) 0  t −t 0 st e − u(t)