(a) What are the three basic units in communication systems? Write briefly the function of each of these.

(b) Write any three applications of the Internet used in communication systems. 

a) 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.

b) Application of internet used in communication system is:

i) E-banking: Financial transactions can be made through this mode.

ii) Internet surfing: Navigation over World Wide Web (www) from one webpage/website to another is called Internet surfing. It is an interesting way of searching and viewing information on any topic of interest.

iii) E-commerce: This is a mode of electronic commerce by which consumers can buy the products or the services over internet.