multiplexing, in communication, technique whereby two or more independent messages, or information-bearing signals, are carried by a single common medium, or channel. When multiplexing is performed, two or more channels are combined into a single channel, or, in a process often called demultiplexing, a single channel is divided into several subchannels. Many different types of multiplexing are possible. One type is frequency-division multiplexing, in which a single frequency channel is subdivided into two or more subchannels, each of which can then carry a smaller range of frequencies than could the original channel. Frequency-division multiplexing is used in television broadcasting, when audio and video signals share a single channel; in stereophonic FM radio broadcasting, when two audio signals share a single channel; and in microwave transmission of long-distance telephone calls, when 60 or more conversations are carried by a single microwave beam. A second type of multiplexing is time-division multiplexing, in which successive small time intervals are used for the transmission of messages over a single channel. Time-division multiplexing is often used in the construction of digital computers. When information can be stored into or retrieved from the computer's memory at a much greater rate than it can be supplied or used by an external device such as a card reader, printer, or teletype terminal, several such low-speed devices can share a single multiplexed data channel.
Questia, a part of Gale, Cengage Learning. www.questia.com
Publication information: Article title: multiplexing. Encyclopedia title: The Columbia Encyclopedia, 6th ed.. © 2012 The Columbia Electronic Encyclopedia © 2012, Columbia University Press. Licensed from Columbia University Press. Used with the permission of Columbia University Press. All Rights Reserved. Publisher: The Columbia University Press. Place of publication: Not available. Publication year: 2013.
This material is protected by copyright and, with the exception of fair use, may not be further copied, distributed or transmitted in any form or by any means.