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Satellite Subcarrier Audio
Satellite subcarrier audio is audio transmitted by way of satellite that uses a separate analog or digital signal carried on a main radio transmission (usually video) on a specific satellite transponder. More technically, it is an already-modulated signal, which is then modulated into another signal of higher frequency and bandwidth. In a more general sense, satellite subcarrier audio is an early form of satellite radio not intended for the consumer market but was initially unencrypted, thus receivable to satellite hobbyists. Original analog video only has one channel per transponder, with subcarriers for audio and automatic transmission identification service ATIS. Non-multiplexed radio stations can also travel in single channel per carrier (SCPC) mode, with multiple carriers (analog or digital) per transponder. This allows each station to transmit directly to the satellite, rather than paying for a whole transponder, or using landlines to send it to an earth station for multi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellite
A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. Many communications satellites are in geostationary orbit above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit, where antennas on the ground have to follow the position of the satellites and switch between satellites frequently. The high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth (signal Processing)
Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to '' passband bandwidth'' or ''baseband bandwidth''. Passband bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a band-pass filter, a communication channel, or a signal spectrum. Baseband bandwidth applies to a low-pass filter or baseband signal; the bandwidth is equal to its upper cutoff frequency. Bandwidth in hertz is a central concept in many fields, including electronics, information theory, digital communications, radio communications, signal processing, and spectroscopy and is one of the determinants of the capacity of a given communication channel. A key characteristic of bandwidth is that any band of a given width can carry the same amount of information, regardless of where that band is located in the frequency spectrum. For exa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Very-small-aperture Terminal
A very-small-aperture terminal (VSAT) is a two-way satellite ground station with a dish antenna that is smaller than 3.8 meters. The majority of VSAT antennas range from 75 cm to 1.2 m. Bit rates, in most cases, range from 4 kbit/s up to 16 Mbit/s. VSATs access satellites in geosynchronous orbit or geostationary orbit to relay data from small remote Earth stations (terminals) to other terminals (in mesh topology) or master Earth station "hubs" (in star topology). VSATs are used to transmit narrowband data (e.g., point-of-sale transactions using credit cards, polling or RFID data, or SCADA), or broadband data (for the provision of satellite Internet access to remote locations, VoIP or video). VSATs are also used for transportable, on-the-move (utilising phased array antennas) or mobile maritime communications. History The concept of the geostationary orbit was originated by Russian theorist Konstantin Tsiolkovsky, who wrote articles on space travel around the begi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase-shift Keying
Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). The modulation is accomplished by varying the sine and cosine inputs at a precise time. It is widely used for wireless LANs, RFID and Bluetooth communication. Any digital modulation scheme uses a finite number of distinct signals to represent digital data. PSK uses a finite number of phases, each assigned a unique pattern of binary digits. Usually, each phase encodes an equal number of bits. Each pattern of bits forms the symbol that is represented by the particular phase. The demodulator, which is designed specifically for the symbol-set used by the modulator, determines the phase of the received signal and maps it back to the symbol it represents, thus recovering the original data. This requires the receiver to be able to compare the phase of the received signal to a reference signal such a system is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mbit/s
In telecommunications, data-transfer rate is the average number of bits ( bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multiples of bits per second (bit/s) and bytes per second (B/s). For example, the data rates of modern residential high-speed Internet connections are commonly expressed in megabits per second (Mbit/s). Standards for unit symbols and prefixes Unit symbol The ISQ symbols for the bit and byte are ''bit'' and ''B'', respectively. In the context of data-rate units, one byte consists of 8 bits, and is synonymous with the unit octet. The abbreviation bps is often used to mean bit/s, so that when a ''1 Mbps'' connection is advertised, it usually means that the maximum achievable bandwidth is 1 Mbit/s (one million bits per second), which is 0.125 MB/s ( megabyte per second), or about 0.1192 MiB/s (mebibyte per second). The Inst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumulus Media Networks
Cumulus Media Networks was an American radio network owned and operated by Cumulus Media. From 2011 until its merger with Westwood One, it controlled many of the radio assets formerly belonging to the American Broadcasting Company (ABC), which was broken up in 2007; Cumulus owned the portion of the network that was purchased by Citadel Broadcasting that year. The network adopted its final name in September 2011, following Cumulus's acquisition of Citadel; prior to this, it had been known as Citadel Media Networks since April 2009, after licensing the "ABC Radio Networks" name from The Walt Disney Company for nearly two years. ABC now operates a revived ABC Radio Network that owns no stations but produces mostly short-form audio content. It was also (as ABC Radio Networks) the penultimate of the major radio networks to still be owned by its original founding company until 2007, CBS Radio being the last. Mutual Broadcasting Network was dissolved in 1999, and then NBC Radio Ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Westwood One (1976–2011)
Westwood One was an American radio network that was based in New York City. At one time, it was managed by CBS Radio, and was later purchased by the private equity firm, The Gores Group. Due to purchases, mergers and other forms of consolidation in the 1980s and 1990s, at one time or another, it had ownership stakes in or syndication rights to some of the most famous brands in network radio, including CBS, NBC, Mutual, CNN, Fox, and Unistar. The company was one of the largest producers and distributors of radio programming in the United States. It broadcast entertainment, news, weather, sports, talk, and traffic programming to about 7,700 radio stations across the United States. The company was the top provider of local traffic reports in the U.S. through its subsidiaries, Metro Networks, Shadow Broadcast Services, SmartRoute Systems, and Sigalert.com. Westwood One also offers weather services; originally using Accuweather, Westwood switched to The Weather Channel in 2009. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Atlanta
Scientific Atlanta, Inc. was a Georgia, United States-based manufacturer of cable television, telecommunications, and broadband equipment. Scientific Atlanta was founded in 1951 by a group of engineers from the Georgia Institute of Technology, and was purchased by Cisco Systems in 2005 for $6.9 billion after Cisco received antitrust clearance for the purchase. The Cisco acquisition of Scientific Atlanta was ranked in the top 10 of largest technology acquisitions in history and was Cisco's largest acquisition to date. Prior to the purchase, Scientific Atlanta had been a Fortune 500 company and was one of the top 25 largest corporations in Georgia. Scientific Atlanta was considered by many to be "the patriarch of Atlanta's technology industry for nearly six decades" and is sometimes referred to as "Atlanta's Microsoft or Hewlett Packard". Products Scientific Atlanta was a supplier of transmission networks for broadband access to the home, set-top cable boxes, cable modems and dig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elevator Music
Elevator music (also known as Muzak, piped music, or lift music) is a type of background music played in rooms where many people come together (that is, with no intention whatsoever to listen to music), and during telephone calls when placed on hold. There is a specific sound associated with elevator music, but it usually involves simple instrumental themes from "soft" popular music, or "light" classical music being performed by slow strings. This type of music was produced, for instance, by the Mantovani Orchestra, and conductors such as Franck Pourcel and James Last, peaking in popularity around the 1970s. More recent types of elevator music may be computer-generated, with the actual score being composed entirely algorithmically. Other uses The term can also be used for kinds of easy listening, piano solo, jazz or middle of the road music, or what are known as "beautiful music" radio stations. This style of music is sometimes used to comedic effect in mass media such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muzak
Muzak is an American brand of background music played in retail stores and other public establishments. The name has been in use since 1934, and has been owned by a division or subsidiary of one or another company ever since. In 1981, Westinghouse Electric Corporation, Westinghouse bought the company and ran it until selling it to the Fields Company of Chicago, publishers of the ''Chicago Sun-Times'', on September 8, 1986. Formerly owned by Muzak Holdings, the brand was purchased in 2011 by Mood Media in a deal worth United States dollar, US$345 million. Muzak was based in various Seattle, Washington locations from 1986 to 1999, after which it moved its headquarters to South Carolina in 2000. The word ''Muzak'' has been a registered trademark since December 21, 1954, of Muzak LLC. In the United States, due in part to the company’s market dominance, ''Muzak'' has come to be used to refer to most forms of background music, regardless of source. It may also be referred to as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission (telecommunications)
In telecommunications, transmission is the process of sending or propagating an analog or digital signal via a medium that is wired, wireless, or fiber-optic. Transmission technologies typically refer to physical layer protocol duties such as modulation, demodulation, line coding, equalization, error control, bit synchronization and multiplexing, but it may also involve higher-layer protocol duties, for example, digitizing an analog signal, and data compression. Transmission of a digital message, or of a digitized analog signal, is known as data transmission. Examples of transmission are the sending of signals with limited duration, for example, a block or packet of data, a phone call, or an email. See also *Radio transmitter In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponder
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight transponder is an automated transceiver in an aircraft that emits a coded identifying signal in response to an interrogating received signal. In a communications satellite, a satellite transponder receives signals over a range of uplink frequencies, usually from a satellite ground station; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals. Satellite/broadcast communications A communications satellite’s channels are called transponders because each is a separate transceiver or repeater. With digital video data compression and multiplexing, several video and audio channels may travel through a single t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
