Write the functions of the following in communication systems: (i) Transmitter (ii) Modulator

Transmitter : A transmitter converts the message signal from the source of information into a form suitable for transmission through a channel.
Modulator : Modulator modulates the message signal, i.e. it superimposes a low-frequency message signal on a high frequency carrier wave, so that the low-frequency message signal can be transmitted over long distances.