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Telecommunication, often used in its plural form or abbreviated astelecom, is the transmission ofinformation over a distance usingelectrical orelectronic means, typically through cables,radio waves, or other communication technologies. These means of transmission may be divided intocommunication channels formultiplexing, allowing for a single medium to transmit several concurrentcommunication sessions. Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include theelectrical telegraph,telephone,television, andradio.
Earlytelecommunication networks used metal wires as the medium for transmitting signals. These networks were used fortelegraphy and telephony for many decades. In the first decade of the 20th century, a revolution inwireless communication began with breakthroughs including those made inradio communications byGuglielmo Marconi, who won the 1909Nobel Prize in Physics. Other early pioneers in electrical and electronic telecommunications include co-inventors of the telegraphCharles Wheatstone andSamuel Morse, numerousinventors and developers of the telephone includingAntonio Meucci,Philipp Reis,Elisha Gray andAlexander Graham Bell, inventors of radioEdwin Armstrong andLee de Forest, as well as inventors of television likeVladimir K. Zworykin,John Logie Baird andPhilo Farnsworth.
Since the 1960s, the proliferation of digital technologies has meant thatvoice communications have gradually been supplemented by data. The physical limitations of metallic media prompted the development of optical fibre. TheInternet, a technology independent of any given medium, has provided global access to services for individual users and further reduced location and time limitations on communications. (Full article...)
Anoptical fiber, oroptical fibre, is a flexibleglass or plasticfiber that can transmitlight from one end to the other. Such fibers find wide usage infiber-optic communications, where they permit transmission over longer distances and at higherbandwidths (data transfer rates) than electrical cables. Fibers are used instead of metalwires because signals travel along them with lessloss and are immune toelectromagnetic interference. Fibers are also used forillumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of afiberscope. Specially designed fibers are also used for a variety of other applications, such asfiber optic sensors andfiber lasers.
Glass optical fibers are typically made bydrawing, while plastic fibers can be made either by drawing or byextrusion. Optical fibers typically include acore surrounded by a transparentcladding material with a lowerindex of refraction. Light is kept in the core by the phenomenon oftotal internal reflection which causes the fiber to act as awaveguide. Fibers that support many propagation paths ortransverse modes are calledmulti-mode fibers, while those that support a single mode are calledsingle-mode fibers (SMF). Multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,050 meters (3,440 ft). (Full article...)
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Paul Julius Gottlieb Nipkow (German:[ˈpaʊlˈgɔtliːpˈnɪpkɔv]; 22 August 1860 – 24 August 1940) was a Germanelectrical engineer and inventor. He invented theNipkow disk, which laid the foundation oftelevision, since his disk was a fundamental component in the first televisions. Hundreds of stations experimented with television broadcasting using his disk in the 1920s and 1930s, until it was superseded by all-electronic systems in the 1940s.
Nipkow has been called the "father of television", together with other early figures of television history likeKarl Ferdinand Braun. (Full article...)
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