( ii) Communication Channel The medium through which information propagate from transmitter to receiver 1S called communication channel.
( iii) Receiver It receives and decode the signal.
Analog Signal
A signal in which current or voltage changes its magnitude continuously with time, is called an analog signal.
Digital Signal
A signal in which current or voltage have only two values, is called a digital signal.
Note An analog signal can be converted suitable Into a digital signal and vice-versa.
Modulation
The process of superimposing the audio signal over a high frequency carrier wave is called modulation.
In the process of modulation anyone characteristic of carrier wave is varied in accordance with the instantaneous value of audio signal( modulating signal).
Need of Modulation