Active Amplitude Modulator

hi every body.........

I am a student at University, studying Communication engineering (bachular degree).

I have a project about designing an Active Amplitude Modulator
the simulation is done using Multisim 9 software.

i would be pleased if any one give me useful information about this subject.

My email address: al_mor3eb8@hotmail.com
my name is Mohammed Al sayyah

thank u very much

waiting ur replays