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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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Orthogonal Frequency-Division Multiplexing ("OFDM) — essentially identical to Coded OFDM (COFDM) — is a digital multi-carrier "modulation scheme, which uses a large number of closely-spaced "orthogonal sub-carriers. Each sub-carrier is modulated with a conventional modulation scheme (such as "quadrature amplitude modulation) at a low "symbol rate, maintaining data rates similar to conventional single-carrier modulation schemes in the same bandwidth. In practice, OFDM signals are generated using the "Fast Fourier transform algorithm.

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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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In the news

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Telecommunications News from Wikinews


March 3, 2011: Telecom Commission of Solomon Islands issues phone company US$1M fine
February 22, 2011: Libya blocks access to Internet
September 1, 2010: Telstra becomes the first in the world to switch to HSPA+ wireless Internet technology

Selected biography

"Samuel Finley Breese Morse (27 April 1791 – 2 April 1872) was an American contributor to the invention of a single-wire telegraph system based on European telegraphs, co-inventor of the "Morse code, and a painter of historic scenes.

Morse was born in Charlestown, Massachusetts (now part of Boston), on April 27, 1791, and educated at Yale College (now Yale University). He studied painting in London and became a successful portrait painter and sculptor. In 1825 he helped found the "National Academy of Design in New York City, and the following year he became the first president of the institution. He continued his painting and became a professor of painting and sculpture at New York University in 1832. About that time he became interested in chemical and electrical experiments and developed apparatus for an "electromagnetic telegraph that he completed in 1836. The following year he filed a caveat, or legal notice, at the patent office in Washington, D.C., and tried without success to obtain European patents for his apparatus. He also invented a code, now known as the Morse code, for use with his telegraph instrument. Several contemporary scientists gave Morse significant financial and technical help with his work on the telegraph and Morse code.

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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