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D2-MAC
D2-MAC is a satellite television transmission standard, a member of Multiplexed Analogue Components family. It was created to solve D-MAC's bandwidth problem on European cable systems. * D2-MAC uses half the data rate of D-MAC * D2-MAC has a reduced vision bandwidth, about 1/2 that of D-MAC. * D2-MAC retains most of the quality of a D-MAC signal—but consumes only 5 MHz of bandwidth. Technical details MAC transmits luminance and chrominance data separately in time rather than separately in frequency (as other analog television formats do, such as composite video). Audio and Scrambling (selective access) * Audio, in a format similar to NICAM was transmitted digitally rather than as an FM sub-carrier. * The MAC standard included a standard scrambling system, EuroCrypt, a precursor to the standard DVB-CSA encryption system. History and politics MAC was developed by the UK's Independent Broadcasting Authority (IBA) and in 1982 was adopted as the transmission format for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplexed Analogue Components
Multiplexed Analogue Components (MAC) was an analog television standard where luminance and chrominance components were transmitted separately. This was an evolution from older color TV systems (such as PAL or SECAM) where there was interference between chrominance and luminance. Originally proposed in the 1980s for use on a Europe-wide Terrestrial television, terrestrial High-definition television, HDTV system, although it was never used terrestrially. However, tests have been done in France with terrestrial transmission but no commercial exploitation. Various systems were developed, collectively known as the "MAC/packet" family. In 1985 these were recommended for Satellite television, satellite and Cable television, cable broadcasts by the European Broadcasting Union, European Broadcasting Union (EBU). C-MAC, C-MAC/packet was intended for Satellite television#Direct-to-home and direct broadcast satellite, Direct Broadcast Satellite (DBS), D-MAC, D-MAC/packet was intended for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D-MAC
Among the family of MAC or Multiplexed Analogue Components systems for television broadcasting, D-MAC is a reduced bandwidth variant designed for transmission down cable. * The data is Bipolar encoding, duobinary coded with a data burst rate of 20.25Mbit/s so that 0° as well as ±90° phasors are used. * D-MAC has a bandwidth of 8.4 MHz versus 27 MHz for C-MAC. * Most cable systems work on EBU 7 MHz channel spacing, so this approach did not work universally. * D-MAC's bandwidth problems were later fixed by D2-MAC. D2-MAC: A fix for D-MAC D-MAC consumed too much bandwidth for many applications, so D2-MAC was designed for European cable TV systems. Luminance and chrominance MAC transmits luminance and chrominance data separately in time rather than separately in frequency (as other analog television formats do, such as composite video). Audio and scrambling (selective access) * Audio, in a format similar to NICAM was transmitted digitally rather than as an FM sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Satellite Broadcasting
British Satellite Broadcasting (BSB) was a television company, headquartered in London, that provided direct broadcast satellite television services to the United Kingdom. They started broadcasting on 25 March 1990. The company was merged with Sky Television plc on 2 November 1990 to form British Sky Broadcasting. History Development In January 1977, the World Administrative Radio Conference assigned each country five high-powered direct broadcast by satellite channels for domestic use. In 1982, after being awarded two of the channels, the BBC proposed its own satellite service, but the government imposed two conditions on it: * Use of a satellite built by United Satellite, a consortium of British Aerospace and Matra Marconi Space (now Airbus Defense and Space), with costs estimated at £24 million per year. * A supplementary charter was agreed in May 1983 which allowed the BBC to borrow up to £225 million to cover the cost of the project, as it was not allowed to call on pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SECAM
SECAM, also written SÉCAM (, ''Séquentiel de couleur à mémoire'', French for ''color sequential with memory''), is an analog color television system that was used in France, some parts of Europe and Africa, and Russia. It was one of three major analog color television standards, the others being PAL and NTSC. This page primarily discusses the SECAM colour encoding system. The articles on broadcast television systems and analog television further describe frame rates, image resolution, and audio modulation. SECAM video is composite video because the luminance (luma, monochrome image) and chrominance (chroma, color applied to the monochrome image) are transmitted together as one signal. All the countries using SECAM are currently in the process of conversion, or have already converted to Digital Video Broadcasting (DVB), the new pan-European standard for digital television. SECAM remained a major standard into the 2000s. History Development of SECAM predates PAL, and be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog High-definition Television Systems
Analog high-definition television has referred to a variety of analog video broadcast television systems with various display resolutions throughout history. Pre-1940 On 2 November 1936 the BBC began transmitting the world's first public regular analog "high definition" television service from the Victorian Alexandra Palace in north London. It therefore claims to be the birthplace of television broadcasting as we know it today. The UK's 405-line system introduced in 1936 was described as "high definition"; however, this was in comparison with the early 30-line (largely) experimental system from the 1920s, and would not be considered high definition by modern standards. John Logie Baird, Philo T. Farnsworth, and Vladimir Zworykin had each developed competing TV systems, but resolution was not the issue that separated their substantially different technologies, it was patent interference lawsuits and deployment issues given the tumultuous financial climate of the late 1920s a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SES Astra
SES Astra SA was a corporate subsidiary of SES, based in Betzdorf, in eastern Luxembourg, that maintained and operated the Astra series of geostationary communication satellites between 2001 and 2011. Formed in 1985 as Société Européenne des Satellites (SES), it was Europe's first private satellite operator. In November 2001, upon the purchase of GE Americom from General Electric (renamed to SES Americom), SES Global was formed as the parent company to SES Americom and SES Astra. SES Astra was formed at that time as a subsidiary company to contain all of SES's existing European based satellite operations. In September 2011, SES Astra and sister subsidiary SES World Skies (formed from SES Americom and SES New Skies) were merged back into SES S.A. to streamline operations under a single management system. Subsidiaries of SES Astra, such as HD Plus and ASTRA Broadband Services became direct subsidiaries of SES. The brand name, ''Astra'', representing the satellite family and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Inventions
The following is a list and timeline of innovations as well as inventions and discoveries that involved British people or the United Kingdom including predecessor states in the history of the formation of the United Kingdom. This list covers innovation and invention in the mechanical, electronic, and industrial fields, as well as medicine, military devices and theory, artistic and scientific discovery and innovation, and ideas in religion and ethics. Factors that historians note spurred innovation and discovery include the 17th century scientific revolution and the 18th/19th century industrial revolution. Another possible influence is British the patent system which had medieval origins and was codified with the Patent Act of 1852. 17th century ;1605 *Bacon's cipher, a method of steganography (hiding a secret message), is devised by Sir Francis Bacon. ;1614 * John Napier publishes his work ''Mirifici Logarithmorum Canonis Descriptio'' introducing the concept of logarithms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video Formats
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems which, in turn, were replaced by flat panel displays of several types. Video systems vary in display resolution, aspect ratio, refresh rate, color capabilities and other qualities. Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, and network streaming. History Analog video Video technology was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) television systems, but several new technologies for video display devices have since been invented. Video was originally exclusively a live technology. Charles Ginsburg led an Ampex research team developing one of the first practica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television Transmission Standards
Television, sometimes shortened to TV, is a telecommunication Media (communication), medium for transmitting moving images and sound. The term can refer to a television set, or the medium of Transmission (telecommunications), television transmission. Television is a mass medium for advertising, entertainment, news, and sports. Television became available in crude experimental forms in the late 1920s, but only after several years of further development was the new technology marketed to consumers. After World War II, an improved form of black-and-white television broadcasting became popular in the United Kingdom and the United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion.Diggs-Brown, Barbara (2011''Strategic Public Relations: Audience Focused Practice''p. 48 In the mid-1960s, color broadcasting was introduced in the U.S. and most other developed countri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television Technology
Large-screen television technology (colloquially big-screen TV) developed rapidly in the late 1990s and 2000s. Prior to the development of thin-screen technologies, rear-projection television was standard for larger displays, and jumbotron, a non-projection video display technology, was used at stadiums and concerts. Various thin-screen technologies are being developed, but only liquid crystal display (LCD), plasma display (PDP) and Digital Light Processing (DLP) have been publicly released. Recent technologies like organic light-emitting diode (OLED) as well as not-yet-released technologies like surface-conduction electron-emitter display (SED) or field emission display (FED) are in development to replace earlier flat-screen technologies in picture quality. Large-screen technologies have almost completely displaced cathode-ray tubes (CRT) in television sales due to the necessary bulkiness of cathode-ray tubes. The diagonal screen size of a CRT television is limited to abou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DVB-T
DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in February, 1998. This system transmits compressed digital audio, digital video and other data in an MPEG transport stream, using coded orthogonal frequency-division multiplexing (COFDM or OFDM) modulation. It is also the format widely used worldwide (including North America) for Electronic News Gathering for transmission of video and audio from a mobile newsgathering vehicle to a central receive point. It is also used in the US by Amateur television operators. Basics Rather than carrying one data carrier on a single radio frequency (RF) channel, COFDM works by splitting the digital data stream into a large number of slower digital streams, each of which digitally modulates a set of closely spaced adjacent sub-carrier frequencies. In the cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DVB-S
Digital Video Broadcasting – Satellite (DVB-S) is the original DVB standard for Satellite Television and dates from 1995, in its first release, while development lasted from 1993 to 1997. The first commercial applications was by Star TV in Asia and Galaxy in Australia, enabling digitally broadcast, satellite-delivered Television to the public.DVB-S was the first DVB standard for satellite, defining the framing structure, channel coding and modulation for 11/12 GHz satellite services It is used via satellites serving every continent of the world. DVB-S is used in both Multiple Channel Per Carrier (MCPC) and Single channel per carrier modes for Broadcast Network feeds as well as for direct-broadcast satellite services like Sky (UK & Ireland) via Astra in Europe, Dish Network and Globecast in the U.S. and Bell Satellite TV in Canada. While the actual DVB-S standard only specifies physical link characteristics and framing, the overlaid transport stream delivered by DVB-S is man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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