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Automatic Transmitter Identification System (television)
The Automatic Transmitter Identification System (ATIS) is a communications protocol used for the station identification of television channels carried on satellite television. ATIS is only required for analog television transmission and only via satellites or earth stations under United States jurisdiction. It is continuously repeated whilst an earth station is using a transponder on a satellite. The Federal Communications Commission (FCC) rules for ATIS are set forth in 47 CFR §25.281. The system was developed in response to the "Captain Midnight" satellite jamming incident. In 2009, HBO and Elmer Musser were awarded a Technology & Engineering Emmy Award for ATIS. ATIS is a Morse code transmission sent on a subcarrier of 7.1 MHz and must activate automatically any time the station is transmitting. The center frequency must be no more than 25 kHz from this nominal value and the frequency deviation must be no more than 25 kHz peak when being modulated. Inje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Protocol
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses pre-determined for that particular situation. The specified behavior is typically independent of how it is to be implemented. Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard. A programming language describes the same for computations, so there is a close analogy between protocols and programming languages: ''protocols ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Deviation
Frequency deviation (f_) is used in FM radio to describe the difference between the minimum or maximum extent of a frequency modulated signal, and the nominal center or carrier frequency. The term is sometimes mistakenly used as synonymous with frequency drift, which is an unintended offset of an oscillator from its nominal frequency. The frequency deviation of a radio is of particular importance in relation to bandwidth, because less deviation means that more channels can fit into the same amount of frequency spectrum. The FM broadcasting range between 87.5 and 108 MHz uses a typical channel spacing of 100 or 200 kHz, with a maximum frequency deviation of +/-75 kHz, in some cases leaving a buffer above the highest and below the lowest frequency to reduce interaction with other channels. The most common FM transmitting applications use peak deviations of +/-75 kHz (100 or 200 kHz spacing), +/-5 kHz (15–25 kHz spacing), +/-2.5 kHz (3.75-12 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airchain
In broadcast engineering for radio or television, the airchain or transmission chain (UK) (sometimes air chain (US) or just chain (UK)) is the path or route an audio or video signal takes on its way through a radio station or television station. The airchain begins with cameras, microphones, CD players, turntables, telephone hybrids, video tape recorders, satellite and other remote feeds, and other input devices in the studio and control room. These feed into a mixing console, possibly via a router. The output then goes to an audio processor, and finally to the transmitter, feedline, and antenna. Often, there is a studio-transmitter link via radio or broadband dedicated circuit (usually T1 or E1 line). The airchain may be all- analogue, all-digital, or most likely some hybrid of the two. All-analog airchains typically use cables terminated in XLR connectors between each device. All-digital airchains also often use XLR connectors, except carrying AES/EBU digital audio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uplink
In a telecommunications network, a link is a communication channel that connects two or more devices for the purpose of data transmission. The link may be a dedicated physical link or a virtual circuit that uses one or more physical links or shares a physical link with other telecommunications links. A telecommunications link is generally based on one of several types of information transmission paths such as those provided by communication satellites, terrestrial radio communications infrastructure and computer networks to connect two or more points. The term ''link'' is widely used in computer networking to refer to the communications facilities that connect nodes of a network. Sometimes the communications facilities that provide the communication channel that constitutes a link are also included in the definition of ''link''. Types Point-to-point A point-to-point link is a dedicated link that connects exactly two communication facilities (e.g., two nodes of a network, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Coordination
Frequency Coordination is a technical and regulatory process that removes or mitigates radio-frequency interference between different radio systems that operate on the same frequency. Normally frequency coordination is a function of an administration, such as a governmental spectrum regulator, as part of a formal regulatory process under the procedures of the Radio Regulations Radio regulation refers to the regulation and licensing of radio in international law, by individual governments, and by municipalities. International regulation The International Telecommunication Union (ITU) is a specialized agency of the Unit ... (an intergovernmental treaty text that regulates the radio frequency spectrum). Before an administrations lets an operator operate a new radio communications network, it must undergo coordination in the following steps: * Inform other operators about the plans * Receive comments if appropriate * Conduct technical discussions with priority networks * Agre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Interference
Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction. The disturbance may degrade the performance of the circuit or even stop it from functioning. In the case of a data path, these effects can range from an increase in error rate to a total loss of the data. Both man-made and natural sources generate changing electrical currents and voltages that can cause EMI: ignition systems, cellular network of mobile phones, lightning, solar flares, and auroras (northern/southern lights). EMI frequently affects AM radios. It can also affect mobile phones, FM radios, and televisions, as well as observations for radio astronomy and atmospheric science. EMI can be used intentionally for radio jamming, as in electronic warfare. History Since the earliest days of radio c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serial Number
A serial number is a unique identifier assigned incrementally or sequentially to an item, to ''uniquely'' identify it. Serial numbers need not be strictly numerical. They may contain letters and other typographical symbols, or may consist entirely of a character string. Applications of serial numbering Serial numbers identify otherwise identical individual units, thereby serving various practical uses. Serial numbers are a deterrent against theft and counterfeit products, as they can be recorded, and stolen or otherwise irregular goods can be identified. Banknotes and other transferable documents of value bear serial numbers to assist in preventing counterfeiting and tracing stolen ones. They are valuable in quality control, as once a defect is found in the production of a particular batch of product, the serial number will identify which units are affected. Some items with serial numbers are automobiles, firearms, electronics, and appliances. Smartphones and other Smar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Number
A telephone number is a sequence of digits assigned to a landline telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices for data transmission via the public switched telephone network (PSTN) or other public and private networks. A telephone number serves as an address for switching telephone calls using a system of destination code routing. Telephone numbers are entered or dialed by a calling party on the originating telephone set, which transmits the sequence of digits in the process of signaling to a telephone exchange. The exchange completes the call either to another locally connected subscriber or via the PSTN to the called party. Telephone numbers are assigned within the framework of a national or regional telephone numbering plan to subscribers by telephone service operators, which may be commercial entities, state-controlled administrations, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Callsign
In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assigned by a government agency, informally adopted by individuals or organizations, or even cryptographically encoded to disguise a station's identity. The use of call signs as unique identifiers dates to the landline railroad telegraph system. Because there was only one telegraph line linking all railroad stations, there needed to be a way to address each one when sending a telegram. In order to save time, two-letter identifiers were adopted for this purpose. This pattern continued in radiotelegraph operation; radio companies initially assigned two-letter identifiers to coastal stations and stations onboard ships at sea. These were not globally unique, so a one-letter company identifier (for instance, 'M' and two letters as a Marc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Words Per Minute
Words per minute, commonly abbreviated wpm (sometimes uppercased WPM), is a measure of words processed in a minute, often used as a measurement of the speed of typing, reading or Morse code sending and receiving. Alphanumeric entry Since words vary in length, for the purpose of measurement of text entry the definition of each "word" is often standardized to be five characters or keystrokes long in English, including spaces and punctuation. For example, under such a method applied to plain English text the phrase "I run" counts as one word, but "rhinoceros" and "let's talk" would both count as two. Karat et al. found in one study of average computer users in 1999 that the average rate for transcription was 32.5 words per minute, and 19.0 words per minute for composition. In the same study, when the group was divided into "fast", "moderate", and "slow" groups, the average speeds were 40 wpm, 35 wpm, and 23 wpm, respectively. With the onset of the era of desktop computers, fas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bit Rate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction with an SI prefix such as kilo (1 kbit/s = 1,000 bit/s), mega (1 Mbit/s = 1,000 kbit/s), giga (1 Gbit/s = 1,000 Mbit/s) or tera (1 Tbit/s = 1,000 Gbit/s). The non-standard abbreviation bps is often used to replace the standard symbol bit/s, so that, for example, 1 Mbps is used to mean one million bits per second. In most computing and digital communication environments, one byte per second (symbol: B/s) corresponds to 8 bit/s. Prefixes When quantifying large or small bit rates, SI prefixes (also known as metric prefixes or decimal prefixes) are used, thus: Binary prefixes are sometimes used for bit rates. The International Standard ( IEC 80000-13) specifies diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pure Tone
Pure may refer to: Computing * A pure function * A pure virtual function * PureSystems, a family of computer systems introduced by IBM in 2012 * Pure Software, a company founded in 1991 by Reed Hastings to support the Purify tool * Pure-FTPd, FTP server software * Pure (programming language), functional programming language based on term rewriting * Pure Storage, a company that makes datacenter storage solutions * Pure (CRIS), a research information system bought by Elsevier. Companies and products * Pure (app), dating app * Pure (restaurant chain), a British fast food chain * Pure Insurance, Privilege Underwriters Reciprocal Exchange * Pure Trading, a Canadian electronic communication network operated by CNQ * Pure Digital, a UK consumer electronics company specialising in DAB radios * Pure Oil, a U.S. chain of gas stations * Propulsion Universelle et Récuperation d'Énergie (PURE), a motorsport engineering company * Pure FM (Portsmouth), a university radio station based ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
