单项选择题
A.Rs、RL、R均加大 B.Rs、R减小,RL加大 C.Rs、RL、R均减小 D.Rs、RL加大,R减小
A.A B.B C.C D.D
A.f2(t)=f1(t-2)ε(t-2) B.f2(t)=f1(t+2)ε(t+2) C.f2(t)=f1(2-t)ε(2-t) D.f2(t)=f1(2-t)ε(t+2)