Tuesday, 28 February 2012

Elements of communication system


Information source: messages come from information source. Communication system transfers messages. Information can be human voice, pictures, computer data, music or any other physical variation in environment.
Transmitter: Transmitter converts the messages coming from information source into a signal suitable for transmission over channel. Transmitter circuit consists of amplifiers and modulators.
Communication channel: it is the medium through which information gets transmitted. Channel can be wired or wireless. Wired communication channels can be twisted pairs, coaxial cables or optical fibers. Wireless communication uses free space as medium
Noise: noise is a random signal. It adds to the information in channel. Noise can be man-made or natural. Natural noise comes from lightening, thunders, or radiation from sun etc. man-made noise is produced by electric motors, fluorescent light etc.
Receiver: receiver is circuit that converts the information coming from channel into the original message signal. It removes the effect of noise. It consists of amplifiers, mixer, local oscillators and demodulators.

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