What are the three basic units in communication systems ? Write briefly the function of each of these.
A communication system consists of three basic units:
(i) Transmitter: This unit is used for transmitting the information after modifying it to a suitable form. It basically consists of a transducer that converts signal in any physical form to electrical signal for transmission. After that, the signal is modulated to transmit over long distances.
(ii) Communication channel: This unit carries the modulated signal from the transmitter to the receiver. Transmission lines act as a communication channel in case of telephony, whereas the free space serves the purpose of communication channel in case of the radio communication.
(iii) Receiver: This unit consists of an antenna, which receives the signal, followed by a demodulator, an amplifier and a transducer. The demodulator demodulates the modulated signal, the amplifier boosts up its intensity and the transducer converts it back again from electrical form to the needed physical form.