4.1.1调幅(AM) 假设h(t)=δt),即滤波器(H(o)=1)为全通下 络,调制信号m(t)叠加直流A0后与载波相乘 SaM(t)=A+m(t]cos at= A cost+m(t)cost SAM/()=A(+O)+o(-02) +2[M(O+0)+M(O-0 m(t) am(t 2021/2/22 CP第四章模拟调制系统2021/2/22 CP 第四章 模拟调制系统 4 4.1.1 调幅(AM) • 假设h(t)=δ(t)，即滤波器（H(ω)=1）为全通网 络，调制信号m(t)叠加直流A0后与载波相乘 • • • ＋ m(t) A0 cos  c t s AM(t) 0 0 ( ) [ ( )]cos cos ( )cos AM c c c s t A m t t A t m t t = + = +    0 ( ) [ ( ) ( )] AM c c S A         = + + − 1 2 [ ( ) ( )] M M     c c  + + + −