what is communication system.

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Communication - Communication is the process of establishing connection or link between two points for information exchange.Typical examples of communication system are mobile communication, radar communication, television broadcasting, radio telephony, line telephony, etc.
Communication system - Communication system is to transmit an information bearing signal, from a source, located at one point, to a user or destination located at another point some distance away.
The essential component of a communication system are information source, input transducer, transmitter, communication channel, receiver & output transducer.These functional elements are represented by blocks.
 
(1) Information Source - A communication system serves to communicate a message or information. This message or information originates in the information source. There can be various message in the form of word, group of words, code, symbols, sound, signal etc.
(2) Input transducer - Transducer is a device which converts one form of energy into another form. The message from the information source may or may not be electrical in nature. In a case when message produced by the information source is not electrical in nature, an input transducer is used to convert it into a time-varying electrical signal.
(3) Transmitter - The function of the transmitter is to process the electrical signal from different aspects. In long distance radio communication or broadcast, signal amplification is necessary before modulation. Modulation is the main function of the transmitter.modulation defined as the process by which some characteristics of a signal called carrier is varied in accordance with the instantaneous value of another singal called modulating signal.
(4) Channel - The function of the channel is to provide a physical connection between the transmitter & the receiver. There are two types of channels, namely point to point & broadcast channels. Examples of point to point to point channels are microwave links, wirelines & optical fibres.
(5) Noise - The noise defined as an unwanted signal which tend to interfere with the required signal.The noise can't be eliminated completely. However , the effect of noise on desired signal can be minimised with the help of several techniques.
(5) Receiver - Receiver is reproduce the message signal in electrical form from the distroted received signal. This reproduction of the original signal is accomplished by a process known as demodulation.
(6) Output transducer - Output transducer is the final stage which is used to convert an electrical message signal into its original form. For example in radio broadcasting, the output transducer is a loudspeaker, which converts the electrical signal in the form of original sound signal.

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