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Sparklies
Sparklies is a form of interference on analogue satellite television transmissions. Sparklies are black or white 'hard' interference dots (as opposed to the 'soft' interference patterns of terrestrial television), caused either by too weak or too strong a signal. When within the satellite's rated reception footprint, sparklies are most likely to be caused by a misaligned dish, or LNBs which are too high- or too low-gain for the dish and receiver. The term "sparklies" is used by British Sky Broadcasting (BSkyB) and a number of hardware makers including Amstrad and Pace. Sparklies do not occur on digital satellite systems; similar problems with digital signals cause MPEG The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by ISO and IEC that sets standards for media coding, including compression coding of audio, video, graphics, and genomic data; and transmission and f ... artifacts. See also * Salt and pepper noise References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Television
Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, phase and frequency of an analog signal. Analog signals vary over a continuous range of possible values which means that electronic noise and interference may be introduced. Thus with analog, a moderately weak signal becomes snowy and subject to interference. In contrast, picture quality from a digital television (DTV) signal remains good until the signal level drops below a threshold where reception is no longer possible or becomes intermittent. Analog television may be wireless ( terrestrial television and satellite television) or can be distributed over a cable network as cable television. All broadcast television systems used analog signals before the arrival of DTV. Motivated by the lower bandwidth requirements of compressed digital signals, beginning in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Television
Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commonly referred to as a satellite dish and a low-noise block downconverter. A satellite receiver then decodes the desired television program for viewing on a television set. Receivers can be external set-top boxes, or a built-in television tuner. Satellite television provides a wide range of channels and services. It is usually the only television available in many remote geographic areas without terrestrial television or cable television service. Modern systems signals are relayed from a communications satellite on the X band (8–12 GHz) or Ku band (12–18 GHz) frequencies requiring only a small dish less than a meter in diameter. The first satellite TV systems were an obsolete type now known as television receive-only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrestrial Television
Terrestrial television or over-the-air television (OTA) is a type of television broadcasting in which the signal transmission occurs via radio waves from the terrestrial (Earth-based) transmitter of a TV station to a TV receiver having an antenna. The term ''terrestrial'' is more common in Europe and Latin America, while in Canada and the United States it is called ''over-the-air'' or simply ''broadcast''. This type of TV broadcast is distinguished from newer technologies, such as satellite television (direct broadcast satellite or DBS television), in which the signal is transmitted to the receiver from an overhead satellite; cable television, in which the signal is carried to the receiver through a cable; and Internet Protocol television, in which the signal is received over an Internet stream or on a network utilizing the Internet Protocol. Terrestrial television stations broadcast on television channels with frequencies between about 52 and 600 MHz in the VHF and UHF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Footprint (satellite)
The footprint of a communications satellite is the ground area that its transponders offer coverage, and determines the satellite dish diameter required to receive each transponder's signal. There is usually a different map for each transponder (or group of transponders), as each may be aimed to cover different areas. Footprint maps usually show either the estimated minimum satellite dish diameter required or the signal strength in each area measured in dBW The decibel watt (dBW or dBW) is a unit for the measurement of the strength of a signal expressed in decibels relative to one watt. It is used because of its capability to express both very large and very small values of power in a short range of .... External links Links to fleet information and footprintsfrom SES. from Intelsat for their fleet of satellites. Links to interactive mapsfor SES World Skies's fleet of satellites. Link to mapsfor Russian Satellite Communications Company satellites Link to satellite footpri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-noise Block Converter
A low-noise block downconverter (LNB) is the receiving device mounted on satellite dishes used for satellite TV reception, which collects the radio waves from the dish and converts them to a signal which is sent through a cable to the receiver inside the building. Also called a low-noise block, low-noise converter (LNC), or even low-noise downconverter (LND),Bains, Geoff. "Getting The Most Out Of An LNB" ''What Satellite & Digital TV'' (November, 2008) pp50-51 the device is sometimes inaccurately called a ''low-noise amplifier'' (''LNA''). The LNB is a combination of low-noise amplifier, frequency mixer, local oscillator and intermediate frequency (IF) amplifier. It serves as the RF front end of the satellite receiver, receiving the microwave signal from the satellite collected by the dish, amplifying it, and downconverting the block of frequencies to a lower block of intermediate frequencies (IF). This downconversion allows the signal to be carried to the indoor satellite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gain (electronics)
In electronics, gain is a measure of the ability of a two-port circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output port by adding energy converted from some power supply to the signal. It is usually defined as the mean ratio of the signal amplitude or power at the output port to the amplitude or power at the input port. It is often expressed using the logarithmic decibel (dB) units ("dB gain"). A gain greater than one (greater than zero dB), that is amplification, is the defining property of an active component or circuit, while a passive circuit will have a gain of less than one. The term ''gain'' alone is ambiguous, and can refer to the ratio of output to input voltage (''voltage gain''), current (''current gain'') or electric power (''power gain''). In the field of audio and general purpose amplifiers, especially operational amplifiers, the term usually refers to voltage gain, but in radio frequency amplifiers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Sky Broadcasting
Sky UK Limited is a British broadcaster and telecommunications company that provides television and broadband Internet services, fixed line and mobile telephone services to consumers and businesses in the United Kingdom. It is a subsidiary of Sky Group and from 2018 onwards, part of Comcast. It is the UK's largest pay-TV broadcaster with 12.7 million customers as of the end of 2019 for its digital satellite TV platform. Sky's flagship products are Sky Q and the internet-based Sky Glass, and its flagship channels are Sky Showcase, Sky Sports and Sky Atlantic. Formed as British Sky Broadcasting (BSkyB) in November 1990 through the merger of Sky Television and British Satellite Broadcasting, it grew into a major media company by the end of the decade, notably owning all the television broadcasting rights for the Premier League and almost all the domestic rights of Hollywood films. Following BSkyB's acquisition of Sky Italia and a majority interest in Sky Deutschland in 2014, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amstrad
Amstrad was a British electronics company, founded in 1968 by Alan Sugar at the age of 21. The name is a contraction of Alan Michael Sugar Trading. It was first listed on the London Stock Exchange in April 1980. During the late 1980s, Amstrad had a substantial share of the PC market in the UK. Amstrad was once a FTSE 100 Index constituent, but since 2007 has been wholly owned by Sky UK. , Amstrad's main business was manufacturing Sky UK interactive boxes. In 2010, Sky integrated Amstrad's satellite division as part of Sky so they could make their own set-top boxes in-house. The company had offices in Kings Road, Brentwood, Essex. History 1960s and 1970s Amstrad (also known as AMSTrad) was founded in 1968 by Alan Sugar at the age of 21, the name of the original company being AMS Trading (Amstrad) Limited, derived from its founder's initials (Alan Michael Sugar). Amstrad entered the market in the field of consumer electronics. During the 1970s they were at the forefron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pace Plc
Pace plc was a British company who developed set-top boxes (STBs), advanced residential gateways, software and services for the pay-TV and broadband services industry. Pace's customers included cable, telco, satellite and IPTV operators. The company was listed on the London Stock Exchange until December 2015, when the company received the last of the regulatory clearances needed to allow a merger with Arris Group to proceed. In 2019, Arris was subsequently acquired by network infrastructure provider CommScope. History The company was founded by Yorkshire born businessmen Barry Rubery, David Hood and Robert Fleming in 1982, taking the name ''Pace Micro Supplies'' in 1983, eventually being renamed to ''Pace Micro Technology plc'' in 1987. It introduced the first low cost commercially available modems in 1985. In 1987, it started selling its first analogue satellite set top receivers. In 1996, it introduced the world's first DVB decoders, for Australian satellite company Gal ... [...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 wid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MPEG
The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by ISO and IEC that sets standards for media coding, including compression coding of audio, video, graphics, and genomic data; and transmission and file formats for various applications.John Watkinson, ''The MPEG Handbook'', p. 1 Together with JPEG, MPEG is organized under ISO/IEC JTC 1/SC 29 – ''Coding of audio, picture, multimedia and hypermedia information'' (ISO/IEC Joint Technical Committee 1, Subcommittee 29). MPEG formats are used in various multimedia systems. The most well known older MPEG media formats typically use MPEG-1, MPEG-2, and MPEG-4 AVC media coding and MPEG-2 systems transport streams and program streams. Newer systems typically use the MPEG base media file format and dynamic streaming (a.k.a. MPEG-DASH). History MPEG was established in 1988 by the initiative of Dr. Hiroshi Yasuda ( NTT) and Dr. Leonardo Chiariglione ( CSELT). Chiariglione was the group's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artifact (error)
In natural science and signal processing, an artifact or artefact is any error in the perception or representation of any information introduced by the involved equipment or technique(s). Computer science In ''computer science'', digital artifacts are anomalies introduced into digital signals as a result of digital signal processing. Microscopy In ''microscopy'', visual artifacts are sometimes introduced during the processing of samples into slide form. Econometrics In ''econometrics'', which trades on computing relationships between related variables, an artifact is a spurious finding, such as one based on either a faulty choice of variables or an over-extension of the computed relationship. Such an artifact may be called a ''statistical artifact''. For instance, imagine a hypothetical finding that presidential approval rating is approximately equal to twice the percentage of citizens making more than $50,000 annually; if 60% of citizens make more than $50,000 annuall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
