Test: Communication Systems - October 6, 2022 - NEET MCQ

Communication is the very act of transmission of information. Irrespective of its nature, every communication system has three essential elements, namely a transmitter, a medium or channel, and a receiver.

The purpose of a transmitter is to convert the message signal produced by the source of information into a suitable form that can be transmitted through the channel that connects the transmitter and the receiver.

If the output of the information source is a non-electrical signal such as a voice signal, then that’s where the transducer comes into play. The transducer converts this voice signal into an electric form before giving it as an input to the transmitter.

Channel imperfection is that the reason for distortion when a transmitted signal propagates along the channel. Moreover, the receiver receives a corrupted version of the transmitted signal thanks to the addition of noise to the transmitted signal.

The receiver does the function of operating on the received signal. The receiver reconstructs a recognizable form of the original message signal in order to deliver the signal to the user of information.

The telephone is the odd one out. Telephones belong to the category of point-to-point communication, whereas all the others belong to the broadcast mode of communication. In point-to-point communication mode, communication takes place over a link between a single transmitter and a receiver. In broadcast mode, there are a large number of receivers corresponding to a single transmitter.

Signal is the electrical analogue of the information produced by the source. It may be defined as a single-valued function of time (that conveys the information) and which, at every instant of time, takes a unique value.

Range is defined as the largest distance between the source and the destination upto which a signal can be received with sufficient strength. Generally, it is the difference between the highest and the lowest values.

A repeater is a combination of a transmitter, an amplifier and a receiver which picks up a signal from the transmitter, amplifies and retransmits it to the receiver sometimes with a change of carrier frequency.

The term baseband refers to the band of frequencies of the original signal, i.e. a signal that is not changed by the modulation, as is produced by the source of information. For example, an audio signal may have a baseband range from 20 to 20,000 hertz.