8 Communication systems 8.1.2 Amplitude Modulation with Sinusoidal signal cos(oct+Ac For convenience. choose 0=0.so y(t=x(t)c(t)=x(t)cos@ t Y(o) X(*(o) C(O)=xo(-)+x6(+l) Y()=2X(m-Jo.)+2X(O+1o)8 Communication systems 8.1.2 Amplitude Modulation with Sinusoidal signal For convenience, choose c =0, so y t x t c t x t t c ( ) = ( ) ( ) = ( )cos ( ) 2 1 ( ) 2 1 ( ) ( ) ( ) ( ) ( )* ( ) 2 1 ( ) c c c c Y j X j j X j j C j Y j X j C j                   = − + + = − + + =