Telefunken was a German radio and television producer, founded in Berlin in 1903 as a joint venture between Siemens & Halske and the Allgemeine Elektrizitäts-Gesellschaft (AEG) ("General electricity company").Prior to World War I, the company set up the first world-wide network of communications and was the first in the world to sell electronic televisions with cathode-ray tubes, in Germany in 1934.
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👉 Telefunken in the context of Ferdinand Braun
Karl Ferdinand Braun (German: [ˈfɛʁdinant ˈbʁaʊ̯n] ; 6 June 1850 – 20 April 1918) was a German applied physicist who shared the 1909 Nobel Prize in Physics with Guglielmo Marconi for their contributions to the development of radio. With his two circuit system, long range radio transmissions and modern telecommunications were made possible. His invention of the phased array antenna in 1905 led to the development of radar, smart antennas, and MIMO. He built the first cathode-ray tube in 1897, which led to the development of television, and the first semiconductor diode in 1874, which co-started the development of electronics and electronic engineering.
Braun was a co-founder of Telefunken, one of the pioneering communications and television companies. He has been called the "father of television" (shared with inventors like Paul Nipkow), the "great-grandfather of every semiconductor ever manufactured", and a co-father of radiotelegraphy, together with Marconi, laying the foundation for all modern wireless systems.
In this Dossier
Telefunken in the context of Digital Radio Mondiale
Digital Radio Mondiale (DRM; mondiale being Italian and French for "worldwide") is a set of digital audio broadcasting technologies designed to work over the bands currently used for analogue radio broadcasting including AM broadcasting—particularly shortwave—and FM broadcasting. DRM is more spectrally efficient than AM and FM, allowing more stations, at higher quality, into a given amount of bandwidth, using xHE-AAC audio coding format. Various other MPEG-4 codecs and Opus are also compatible, but the standard now specifies xHE-AAC.
Digital Radio Mondiale is also the name of the international non-profit consortium that has designed the platform and is now promoting its introduction. Radio France Internationale, TéléDiffusion de France, BBC World Service, Deutsche Welle, Voice of America, Telefunken (now Transradio) and Thomcast (now Ampegon) took part at the formation of the DRM consortium.
Telefunken in the context of Cavity magnetron
The cavity magnetron is a high-power vacuum tube used in early radar systems and subsequently in microwave ovens and in linear particle accelerators. A cavity magnetron generates microwaves using the interaction of a stream of electrons with a magnetic field, while moving past a series of cavity resonators, which are small, open cavities in a metal block. Electrons pass by the cavities and cause microwaves to oscillate within, similar to the functioning of a whistle producing a tone when excited by an air stream blown past its opening. The resonant frequency of the arrangement is determined by the cavities' physical dimensions. Unlike other vacuum tubes, such as a klystron or a traveling-wave tube (TWT), the magnetron cannot function as an amplifier for increasing the intensity of an applied microwave signal; the magnetron serves solely as an electronic oscillator generating a microwave signal from direct-current electricity supplied to the vacuum tube.
The use of magnetic fields as a means to control the flow of an electric current was spurred by the invention of the Audion by Lee de Forest in 1906. Albert Hull of General Electric Research Laboratory, USA, began development of magnetrons to avoid de Forest's patents, but these were never completely successful. Other experimenters picked up on Hull's work and a key advance, the use of two cathodes, was introduced by Habann in Germany in 1924. Further research was limited until Okabe's 1929 Japanese paper noting the production of centimeter-wavelength signals, which led to worldwide interest. The development of magnetrons with multiple cathodes was proposed by A. L. Samuel of Bell Telephone Laboratories in 1934, leading to designs by Postumus in 1934 and Hans Hollmann in 1935. Production was taken up by Philips, General Electric Company (GEC), Telefunken and others, limited to perhaps 10 W output. By this time the klystron was producing more power and the magnetron was not widely used, although a 300 W device was built by Aleksereff and Malearoff in the USSR in 1936 (published in 1940).
Telefunken in the context of Abraham Esau
Robert Abraham Esau (7 June 1884 – 12 May 1955) was a German physicist.
After receipt of his doctorate from the University of Berlin, Esau worked at Telefunken, where he pioneered very high frequency (VHF) waves used in radar, radio, and television, and he was president of the Deutscher Telefunken Verband. During World War I, he was a prisoner of war of the French; he was repatriated to Germany in 1919. In 1925, he was appointed professor at the University of Jena, where he also served as rector. From 1933, Esau was the State Councilor in Thuringia.