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In the case of a landline phone call, the source is the person calling, the transmitter is their telephone, the channel is the wire, the receiver is another telephone and the destination is the person using the second telephone. [10] [2] [5] To apply this model accurately to real-life cases, some of the components may have to be repeated. For ...
The Shannon–Weaver model was initially formulated in analogy to how telephone calls work but is intended as a general model of all forms of communication. In the case of a landline phone call, the person calling is the source and their telephone is the transmitter translating the message into an electric signal. The wire acts as the channel.
It was later published in 1949 as a book titled The Mathematical Theory of Communication (ISBN 0-252-72546-8), which was published as a paperback in 1963 (ISBN 0-252-72548-4). The book contains an additional article by Warren Weaver, providing an overview of the theory for a more general audience. [12]
In practice, most intercontinental communication will use the Asynchronous Transfer Mode (ATM) protocol (or a modern equivalent) on top of optic fibre. This is because for most intercontinental communication the Internet shares the same infrastructure as the public switched telephone network.
The earliest end-to-end analog telephone networks to be modified and upgraded to transmission networks with Digital Signal 1 (DS1/T1) carrier systems date back to the early 1960s. They were designed to support the basic 3 kHz voice channel by sampling the bandwidth-limited analog voice signal and encoding using pulse-code modulation (PCM).
PSTN network topology is the switching network topology of a telephone network connected to the public switched telephone network (PSTN).. In the United States and Canada, the Bell System network topology was the switching system hierarchy implemented and operated from c. 1930 to the 1980s for the purpose of integrating the diverse array of local telephone companies and telephone numbering ...
Some of the oldest methods of telecommunications implicitly use many of the ideas that would later be quantified in information theory. Modern telegraphy, starting in the 1830s, used Morse code, in which more common letters (like "E", which is expressed as one "dot") are transmitted more quickly than less common letters (like "J", which is expressed by one "dot" followed by three "dashes").
Therefore, the telephone numbers also count involutions. The problem of counting involutions was the original combinatorial enumeration problem studied by Rothe in 1800 [1] and these numbers have also been called involution numbers. [5] [6] In graph theory, a subset of the edges of a graph that touches each vertex at most once is called a matching.