Portal:Telecommunication

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Telecommunication

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Telecommunications refers to wave-based communication technology through media such as air, cables etc. Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded drumbeats, lung-blown horns, or sent by loud whistles, for example. In the modern age of electricity and electronics, telecommunications now also includes the use of electrical devices such as telegraphs, telephones, and teleprinters, the use of radio and microwave communications, as well as fiber optics and their associated electronics, plus the use of orbiting satellites and the Internet.

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Waveguide17-with-UBR120-flanges.svg

In electromagnetics and communications engineering, the term waveguide may refer to any linear structure that guides electromagnetic waves. However, the original and most common meaning is a hollow metal pipe used for this purpose.

A dielectric waveguide employs a solid dielectric rod rather than a hollow pipe. An optical fibre is a dielectric guide designed to work at optical frequencies. Transmission lines such as microstrip, coplanar waveguide, stripline or coax may also be considered to be waveguides.

The electromagnetic waves in (metal-pipe) waveguide may be imagined as travelling down the guide in a zig-zag path, being repeatedly reflected between opposite walls of the guide. For the particular case of rectangular waveguide, it is possible to base an exact analysis on this view. Propagation in dielectric waveguide, may be viewed in the same way, with the waves confined to the dielectric by total internal reflection at its surface.

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A diagram of radio waves and radio transmission
Credit: LadyofHats

This diagram shows both the position of radio waves in the electromagnetic spectrum (logarithmic scale) as well as how radio waves are used for communication.

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Guglielmo Marchese Marconi, GCVO (25 April 1874-20 July 1937) was an Italian inventor, best known for his development of a practical radiotelegraph system, which served as the foundation for the establishment of numerous affiliated companies worldwide. He shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun, "in recognition of their contributions to the development of wireless telegraphy". While growing up, Marconi had an intense early interest in science, and was especially fascinated by electricity.

Did you know?

...that Intelsat 1, known as Early Bird, launched in 1965, provided either 240 voice circuits or one two-way television channel between the United States and Europe.

...that the first telephone message was transmitted in 1876 from one room in Alexander Graham Bell’s house to another.

...that in 1880 France rewarded Bell the Volta Prize, worth 50,000 francs, for his invention.

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