Any device or circuit by means of which a desired signal is impressed upon a higher-frequency periodic wave known as a carrier. The process is called modulation. The modulator may vary the amplitude, frequency, or phase of the carrier.
The process in which massege is place over a carrier signal is known as modulation.This process take place in transmitter.Demodulation is its opposite it take place in receivers. it is the process in which the carrier signal is adjusted according to the message signal,which is to be sent according to the requirement by the system. so its nothing but the adjustment of a particular thing.
module is like a money taht full of pesos