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Multiplexed Analog 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 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 and cable broadcasts by the European Broadcasting Union (EBU). C-MAC/packet was intended for Direct Broadcast Satellite (DBS), D-MAC/packet was intended for wide-band cable, and D2-MAC/packet was intended both for DBS and narrow-band cable. History MAC was originally developed by the Independent Broadcasting Authority (IBA) (dates unknown) in the UK ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAL And D2-MAC Transmission
Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 frames) per second, and associated with CCIR analogue broadcast television systems B, D, G, H, I or K. The articles on analog broadcast television systems further describe frame rates, image resolution, and audio modulation. PAL video is composite video because luminance (luma, monochrome image) and chrominance (chroma, colour applied to the monochrome image) are transmitted together as one signal. A latter evolution of the standard, PALplus, added support for widescreen broadcasts with no loss of vertical resolution, while retaining compatibility with existing sets. Almost all of the countries using PAL are currently in the process of conversion, or have already converted transmission standards to DVB, ISDB or DTMB. Due to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Television
Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio (commonly 16:9) in contrast to the narrower format of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TV-Sat 2
TV-SAT 2 or TVSAT-2 was a West German communications satellite which was to have been operated by Deutsche Bundespost. It was intended to be used to provide television broadcast services to Europe. It was constructed by Aérospatiale, based on the Spacebus 300 satellite bus, and carried five Ku-band transponders. At launch it had a mass of , and an expected operational lifespan of eight years. Launch TV-SAT 2 was launched with Hipparcos satellite by Arianespace using an Ariane 44LP H10 launch vehicle flying from ELA-2 at Centre Spatial Guyanais, Kourou, French Guiana. The launch took place at 23:25:53 UTC on 8 August 1989. It was a Spacebus 300 satellite bus. Mission TV-SAT 2 was placed into a geostationary orbit at a longitude of 19.2° West. It was available on 25 August 1989 to broadcast the Berlin's TV show. It was leased to TeleTV AS and co-located with Intelsat 702 in 1995. In November 1998, TV-Sat 2 was leased to Eutelsat Eutelsat S.A. is a French satellite ope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E-MAC
C-MAC is the television technology variant approved by the European Broadcasting Union (EBU) for satellite transmissions. The digital information is modulated using 2-4PSK ( phase-shift keying), a variation of quadrature PSK where only two of the phaser angles (±90°) are used. * The data capacity for C-MAC is 3Mbit/s. * C-MAC data has to be sent to the transmitter separately from the vision. * The transmitter switches between FM (vision) and PSK (sound/data) modulation during each television line period. C-MAC variants : E-MAC E-MAC (Extended MAC) is 16:9 version of C-MAC. Originally E-MAC was designed for 15:9 pictures, it later adopted the 16:9 aspect ratio. * In E-MAC all the 4:3 information is transmitted exactly as in C-MAC so that C-MAC receivers are still compatible. * E-MAC hides extra luminance and chrominance information in the field blanking interval and parts of the line blanking interval. * E-MAC has a lower data capacity because luminance is hidden where data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Widescreen
Widescreen images are displayed within a set of aspect ratios (relationship of image width to height) used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ratio greater than the standard 1.37:1 Academy aspect ratio provided by 35 mm film. For television, the original screen ratio for broadcasts was in fullscreen 4:3 (1.33:1). Largely between the 1990s and early 2000s, at varying paces in different nations, 16:9 (1.78:1) widescreen TV displays came into increasingly common use. They are typically used in conjunction with high-definition television (HDTV) receivers, or Standard-Definition (SD) DVD players and other digital television sources. With computer displays, aspect ratios wider than 4:3 are also referred to as widescreen. Widescreen computer displays were previously made in a 16:10 aspect ratio (e.g. 1680 × 1050), but now are usually 16:9 (e.g. 1920 × 1080). Film History Widescreen was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Forces Radio And Television Service
The American Forces Network (AFN) is a government television and radio broadcast service the U.S. military provides to those stationed or assigned overseas. Headquartered at Fort George G. Meade, Maryland, AFN's broadcast operations, which include global radio and television satellite feeds, emanate from the AFN Broadcast Center/Defense Media Center in Riverside, California. AFN was founded on 26 May 1942, in London as the Armed Forces Radio Service (AFRS). History The American Forces Network can trace its origins to 26 May 1942, when the War Department established the Armed Forces Radio Service (AFRS). A television service was first introduced in 1954 with a pilot station at Limestone Air Force Base, Maine. In 1954, the television mission of AFRS was officially recognized and AFRS (Armed Forces Radio Service) became AFRTS (Armed Forces Radio and Television Service). All of the Armed Forces broadcasting affiliates worldwide merged under the AFN banner on 1 January 1998. On 21 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primestar
PrimeStar was a U.S. direct broadcast satellite broadcasting company formed in 1991 by a consortium of cable television system operators ( TCI Satellite Entertainment Group, Time Warner Cable, Cox Communications, Comcast and MediaOne) and GE Americom, the satellite arm of General Electric, collectively referred to as the ''PrimeStar Partners''. PrimeStar was the first medium-powered DBS system in the United States but slowly declined in popularity with the arrival of DirecTV in 1994 and Dish Network in 1996. Technology PrimeStar was a medium-powered DBS-style system utilizing FSS technology that used a larger 3-foot (91 cm) satellite dish to receive signals. Broadcast originally in analog, they later converted to digital technology. The system used the DigiCipher 1 system for conditional access control and video compression. The video format was MPEG-2. Primestar's satellite receivers were made by General Instrument. PrimeStar was owned by a consortium of cable tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optus
Singtel Optus Pty Limited (commonly referred to as Optus) is an Australian Telecommunications in Australia, telecommunications company headquartered in Macquarie Park, New South Wales, Australia. It is a wholly owned subsidiary of Singapore, Singaporean telecommunications company Singtel. Optus is the List of mobile network operators of the Asia Pacific region#Australia, second-largest wireless carrier in Australia, with 10.5 million subscribers as of 2019. The company trades under the Optus brand, while maintaining several wholly owned subsidiaries, such as Uecomm in the network services market and Alphawest in the ICT services sector. To provide services, Optus mostly owns and operates its own network infrastructure, It provides services both directly to end users and also acts as a wholesaler to other service providers such as Exetel and Amaysim. Through its Optus 'Yes' brand, it provides broadband, and wireless internet services. Other wholesale services include Satellite an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multichoice
MultiChoice is a South African company that operates DStv, a major satellite television service in Sub-Saharan Africa and GOtv, a minor service operating in over 9 countries of this area and Showmax service. MultiChoice was formed out of the subscriber-management branch of the M-Net terrestrial pay television company, and broadcasts the full range of M-Net channels on the DStv service. MultiChoice is owned by the media conglomerate of the same name. One of the subsidiaries of MultiChoice is DStv Now, renamed as DStv App, a service that delivers television transmission to mobile devices such as laptops, smart phones and notebooks. Formerly, MultiChoice had operations in the Scandinavian, Benelux, Italy, Eastern Europe, Greek & Cypriot regions under the Filmnet TV service, Egypt under CNE (Cable Network of Egypt), Middle East under Gulf TV and Arab Radio and Television Network & Thailand under UBC (United Broadcasting Corporation). In 2020, MultiChoice had a total subscriber ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B-MAC
B-MAC is a form of analog video encoding, specifically a type of Multiplexed Analogue Components (MAC) encoding. MAC encoding was designed in the mid 80s for use with Direct Broadcast Satellite systems. Other analog video encoding systems include NTSC, PAL and SECAM. Unlike the FDM method used in those, MAC encoding uses a TDM method. B-MAC was a proprietary MAC encoding used by Scientific-Atlanta for encrypting broadcast video services; the full name was "Multiple Analogue Component, Type B". B-MAC uses teletext-style non-return-to-zero (NRZ) signaling with a capacity of 1.625 Mbit/s. The video and audio/data signals are therefore combined at baseband. * Both PAL (626/50) and NTSC (525/60) versions of B-MAC were developed and used. User base (PAL/NTSC zones) * This system was used in South Africa and Australia (for TVRO until 2000). * B-MAC was used for satellite broadcasts of the American Forces Radio and Television Service from the early 1980s until 1996-1997 when the ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-MAC
In television electronics, A-MAC carries digital information: sound, and data-teletext on an FM subcarrier at 7 MHz. Since the vision bandwidth of a standard MAC signal is 8.4 MHz, the horizontal resolution on A-MAC has to be reduced to make room for the 7 MHz carrier. ''A-MAC has not been used in service.'' 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 subcarrier. * The MAC standard included a standard scrambling system, EuroCrypt, a precursor to the standard DVB-CSA encryption system. TV transmission systems * Analog high-definition television systems * PAL, what MAC technology tried to replace * SECAM, what MAC technology tried to replace * A-MAC * B-MAC * C-MAC * D-MAC * E-MAC * S-MAC * D2-MAC ... [...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] |
