Channel | communications | Britannica (original) (raw)

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• component of communication model
  • 
    In communication: Linear models
    …information source, a transmitter, a channel of transmission, a receiver, and a destination—all arranged in linear order. Messages (electronic messages, initially) were supposed to travel along this path, to be changed into electric energy by the transmitter, and to be reconstituted into intelligible language by the receiver. In time, the…
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role in

television transmission and reception

• 
  In television: Bandwidth requirements
  …picture information over the television channel. If, as is stated above, the televised image is dissected, within a few hundredths of a second, into approximately 200,000 pixels, then the electrical impulses corresponding to the pixels must pass through the channel at a rate of several million per second. Moreover, since…
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• UHF signals

  • In UHF
    …typically carry televison signals on channels 14 through 83.
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• VHF signals

  • In VHF
    …television stations that broadcast on channels 2 through 13 use VHF frequencies, as do FM radio stations. Many amateur radio operators also transmit on frequencies within the VHF band.
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• cable television

  • In cable television
    …the systems provide additional television channels. Some of these systems can deliver 50 or more channels because they distribute signals occurring within the normal television broadcast band as well as nonbroadcast frequencies. A frequency-conversion device is connected to the television set of the subscriber to accommodate these signals of nonbroadcast…
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• information theory

  • 
    In information theory: Shannon’s communication model
    The channel is the medium that carries the message. The channel might be wires, the air or space in the case of radio and television transmissions, or fibre-optic cable. In the case of a signal produced simply by banging on the plumbing, the channel might be…
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• optical communication

  • 
    In telecommunications media: Optical transmission
    Two kinds of optical channels exist: the unguided free-space channel, where light freely propagates through the atmosphere, and the guided optical fibre channel, where light propagates through an optical waveguide.
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• telecommunication systems

  • 
    In telecommunication: Bit mapping
    Some transmission channels (telephone wires are one example) may not have the bandwidth capability required for the increased number of binary samples and would distort the digital signals. Thus, although the accuracy required determines the number of quantization levels used, the resultant binary sequence must still be…
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