8 Communication systems 8. 1.1 Amplitude Modulation with Complex Exponential Carrier (1)Modulation Theory Exponential carrier: c(t=e For convenience, let 0c=0, so c(t)=e Output signal( modulated signal): y(t=x(te! Y(o=X(o)*C(o) 2元 C()=26(-Ol) Y(o=X(o-jo)8 Communication systems 8.1.1 Amplitude Modulation with Complex Exponential Carrier Exponential carrier: For convenience, let c =0, so ( ) ( ) c c j t c t e  + = j t c c t e  ( ) = Output signal(modulated signal): j t c y t x t e  ( ) = ( ) ( ) ( ) ( ) 2 ( ) ( )* ( ) 2 1 ( ) c c Y j X j j C j Y j X j C j             = − = − = (1) Modulation Theory