Portal:Telecommunication

The Telecommunication Portal

Earth station at the satellite communication facility in Raisting, Bavaria, Germany

Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the human voice, but with a similar scale of expediency; thus, slow systems (such as postal mail) are excluded from the field.

The transmission media in telecommunication have evolved through numerous stages of technology, from beacons and other visual signals (such as smoke signals, semaphore telegraphs, signal flags, and optical heliographs), to electrical cable and electromagnetic radiation, including light. Such transmission paths are often divided into communication channels, which afford the advantages of multiplexing multiple concurrent communication sessions. Telecommunication is often used in its plural form.

Other examples of pre-modern long-distance communication included audio messages, such as coded drumbeats, lung-blown horns, and loud whistles. 20th- and 21st-century technologies for long-distance communication usually involve electrical and electromagnetic technologies, such as telegraph, telephone, television and teleprinter, networks, radio, microwave transmission, optical fiber, and communications satellites.

A revolution in wireless communication began in the first decade of the 20th century with the pioneering developments in radio communications by Guglielmo Marconi, who won the Nobel Prize in Physics in 1909, and other notable pioneering inventors and developers in the field of electrical and electronic telecommunications. These included Charles Wheatstone and Samuel Morse (inventors of the telegraph), Antonio Meucci and Alexander Graham Bell (some of the inventors and developers of the telephone, see Invention of the telephone), Edwin Armstrong and Lee de Forest (inventors of radio), as well as Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth (some of the inventors of television).

According to Article 1.3 of the Radio Regulations (RR), telecommunication is defined as « Any transmission, emission or reception of signs, signals, writings, images and sounds or intelligence of any nature by wire, radio, optical, or other electromagnetic systems.» This definition is identical to those contained in the Annex to the Constitution and Convention of the International Telecommunication Union (Geneva, 1992).

The early telecommunication networks were created with copper wires as the physical medium for signal transmission. For many years, these networks were used for basic phone services, namely voice and telegrams. Since the mid-1990s, as the internet has grown in popularity, voice has been gradually supplanted by data. This soon demonstrated the limitations of copper in data transmission, prompting the development of optics. (Full article...)

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The atmospheric attenuation of microwaves in dry air with a precipitable water vapor level of 0.001 mm. The downward spikes in the graph corresponds to frequencies at which microwaves are absorbed more strongly, such as by oxygen molecules.

Microwave transmission is the transmission of information by electromagnetic waves with wavelengths in the microwave range (1 m - 1 mm) of the electromagnetic spectrum. Microwave signals are normally limited to the line of sight, so long-distance transmission using these signals requires a series of repeaters forming a microwave relay network. It is possible to use microwave signals in over-the-horizon communications using tropospheric scatter, but such systems are expensive and generally used only in specialist roles.

Although an experimental 40-mile (64 km) microwave telecommunication link across the English Channel was demonstrated in 1931, the development of radar in World War II provided the technology for practical exploitation of microwave communication. During the war, the British Army introduced the Wireless Set No. 10, which used microwave relays to multiplex eight telephone channels over long distances. A link across the English Channel allowed General Bernard Montgomery to remain in continual contact with his group headquarters in London. (Full article...)
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Dr Ronald Hugh Barker
Ronald Hugh Barker FIEE (1915 – 7 October 2015) was an Irish physicist and inventor of Barker code for digital synchronisation. He was a member of the Institution of Engineering and Technology (IET) for 70 years. Born in Dublin, Ireland to English parents, Barker excelled in mathematics, becoming keen on electronics. He is best known for his ground-breaking work on synchronising digital communication systems and framing of received data, using digital codes (see frame slip). These digital codes are known as Barker code. The method was initially researched at SRDE Royal Signals Research Establishment, just after World War II for use in radar, rocket telemetry and digital speech. In 1952, Barker found 7 Barker sequences up to a length of 13 useful for correlation. These sequences are widely used in most data transmissions today. Examples of applications are radar, mobile phone technology, telemetry, digital speech, ultrasound imaging and testing, GPS and Wi-Fi, etc. (Full article...)

Did you know (auto-generated) - load new batch

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  • ... that Nabela Qoser, a Hong Kong news reporter of Pakistani descent, learnt Cantonese as a child by watching television?
  • ... that after a show host on Orlando-area radio station WTLN hired a hitman to kill his former lover's husband, the intended victim began a campaign to urge advertisers to boycott the station?
  • ... that Christian radio station KIXL near Austin, Texas, pulled an anti-pornography program off-air in mid-transmission because of its graphic descriptions of gay sex?
  • ... that to prevent spoilers, the name of the American reality singing competition The Masked Singer is not listed on contracts with celebrities competing on the show?
  • ... that a "North Dakota joke of the mornin'" was a feature on Montana radio station KGRZ because the station's owner and morning show host hailed from that state?
  • ... that Vermont radio station WFAD was ordered to shut down just two weeks after it launched?

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