4.7.2幅度调制(AM)与解调 f f⊙) 4 ↑F(O) c(t)=cos@t f(t)=[4+f(t)]cos@ot -0m0 m 0 F(0)=A[6(0+0)]+6(0-0】 F.(o) (Aπ)》 (Aπ) +Fo+a,)+Fo-a】 1 2 -00 0 00 04.7.2 幅度调制(AM)与解调 f(t) 0 c t t ( ) cos A0 f (t) c 0 ( ) Fc 0 0 2 1 ( ) ( A0 ) A0 m F ( ) m 0 1 0 0 ( ) [ ( )]cos c f t A f t t [ ( ) ( )] 2 1 ( ) [ ( )] ( )] 0 0 0 0 0 F F Fc A