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This glossary of terms used in broadcasting is a list of definitions of terms and concepts related to both radio and television broadcasting, along with the industry in general.
A modulation technique used in electronic communication where the amplitude (signal strength) of the wave is varied in proportion to that of the message signal. Developed in the early 1900s, this technique is most commonly used for transmitting an audio signal via a radio wave measured in kilohertz (kHz). See AM broadcasting.
A broadcast clock is a diagram produced by a program director or a producer to illustrate where each programming element appears in a typical hour.
Authorization for a radio or television station within their respective country to operate, usually with specifications and restrictions on power input, antenna placement, interference mitigation, and in some cases, the specific hours a station can operate.
1. A specific interruption of regularly scheduled programming for coverage of a major news event.
1. A frequency designation for use by a radio or television station by a broadcasting regulator. More commonly associated with television, see television channel.
(North America) A city or town designation for a radio or television station by the terms of its broadcast license, e.g., "licensed to serve". In the United States, used in conjunction with a radio or television station's call sign for a station identification at regular intervals.
(North America) A former definition for high-powered AM stations with the maximum protection from interference by other stations that use the same frequency, arranged by international treaty. Defined by the FCC as Class I-A stations, this was retired in favor of Class A status in the 1980s.
A part of a program played before the title sequence, usually featuring a cliffhanger or prefiguring the plot of the episode to follow.
A radio antenna with two identical dipole antennas mounted at right angles to each other and fed in phase quadrature, resulting in the two currents applied being 90 degrees out of phase. Nicknamed a "turnstile antenna" as the antenna resembles a turnstile when viewed horizontally. Commonly used in FM broadcasting. [5]
Digital on-screen graphic: A common practice of displaying on-screen the logo of a television station, a network, a sponsoring company or the program itself. Commonly referred to as a "bug" because it looks like an insect is hanging out in the corner of the screen, typically as a translucent image in the right hand bottom corner. Controversial due to "screenburn" issues, found to be distracting, among other reasons.
Shorthand for "educational and informative", part of a series of regulations on children's television programming in the United States. [7] [8]
A news service based out of New York, New York, United States, with multiple international bureaus and features punditry programming with a largely conservative slant. Owned by Fox Corporation.
The number of occurrences of a repeating event per unit of time.
A modulation technique used in electronic communication where the instantaneous frequency of the wave is varied, with the instantaneous frequency deviation having a functional relation to the modulating signal amplitude. Invented by Edwin Howard Armstrong, this technique is most commonly used for transmitting an audio signal via a radio wave measured in megahertz (MHz). See FM broadcasting.
1. A radio or television station generally not linked to a major network.
Thousand cycles per second. Used electromagnetically to measure medium wave and short wave frequencies.
The appearance of black bars at the top and bottom of a picture when 16:9 or 14:9 widescreen material is shown on 4:3 sets.
A written record of broadcasting. There are typically three logs:
A specific spectrum of the medium frequency (MF) radio band allocated for AM radio broadcasting.
Million cycles per second. Used electromagnetically to measure FM broadcasts and television.
A former major radio network in the United States established in 1934 as a cooperative among affiliate stations.
A system which distributes programming to multiple stations simultaneously, or slightly delayed, for the purpose of extending total broadcast coverage beyond the limits of a single radio or television signal.
A scrolling ticker at the bottom of the display of television content. It is usually reserved for text headlines or numeric statistics (or both) depending upon the focus of the channel.
A radio or television station in the United States that does not accept any on-air advertising. Some early NCE stations were founded as extensions of area universities or school districts and offered (and in some cases, still offer) in-school educational programming.
1. A radio or television station that operates without legal authorization by their respective country's broadcasting regulator. Depending on the country, said regulators can enforce penalties on the operators and confiscate equipment. [11] In the United Kingdom, stations like Radio Caroline and Radio Atlanta proliferated in the 1960s via offshore transmissions as a challenge to the BBC's monopoly on radio broadcasting. [12] [13]
A form of electronic media outlets whose primary mission is public service. Usually funded by outside and diverse sources including licence fees, individual contributions, public financing and commercial financing. Can be operated on either a national level via a singular organization (e.g., the BBC), or on a local level via a network of affiliated stations.
The description of programming and content broadcast over a radio station. Can be defined by genre, musical selections, or other thematic elements. Sometimes employed to reach a specific age group or demographic.
1. The broadcast of the same program from multiple transmitters.
American satellite radio platform.
A small portion (usually one or two sentences) of an audio recording (often an interview) used to illustrate a news story in the words of the interviewee (c.f. a quotation from a politician).
A procedure commonly used on radio and television stations in the United States in which the respective station's call sign and city of license is read aloud on radio and displayed visually on television (and in some instances, read aloud). Typically done on an hourly basis.
1. Recording studio: a specialized facility used for sound recording, mixing and audio production.
A monopole antenna consisting of one or more horizontal wires suspended between two supports and insulated from them at the ends, resulting in a "T" shape. These supports can either be a radio mast or a building. Developed as an outgrowth of wireless telegraphy, it is still typically used for shortwave transmissions, amateur radio, and some medium wave AM stations. [19] [20]
An electronic device connected to an antenna that generates a radio frequency alternating current. When this current is applied to the antenna, it is excited and radiates radio waves. [21]
A television series in which two or more regular programs are rotated in the same time slot, sometimes with an umbrella title.
Defunct American satellite radio platform.
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.
Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broadcast television, in which the television signal is transmitted over-the-air by radio waves and received by a television antenna attached to the television; or satellite television, in which the television signal is transmitted over-the-air by radio waves from a communications satellite orbiting the Earth, and received by a satellite dish antenna on the roof. FM radio programming, high-speed Internet, telephone services, and similar non-television services may also be provided through these cables. Analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation.
A television broadcaster or television network is a telecommunications network for the distribution of television content, where a central operation provides programming to many television stations, pay television providers or, in the United States, multichannel video programming distributors. Until the mid-1980s, broadcast programming on television in most countries of the world was dominated by a small number of terrestrial networks. Many early television networks such as the BBC, CBS, CBC, NBC or ABC in the USA and in Australia evolved from earlier radio networks.
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 applied to the antenna. When excited by this alternating current, the antenna radiates radio waves.
Medium wave (MW) is the part of the medium frequency (MF) radio band used mainly for AM radio broadcasting. The spectrum provides about 120 channels with more limited sound quality than FM stations on the FM broadcast band. During the daytime, reception is usually limited to more local stations, though this is dependent on the signal conditions and quality of radio receiver used. Improved signal propagation at night allows the reception of much longer distance signals. This can cause increased interference because on most channels multiple transmitters operate simultaneously worldwide. In addition, amplitude modulation (AM) is often more prone to interference by various electronic devices, especially power supplies and computers. Strong transmitters cover larger areas than on the FM broadcast band but require more energy and longer antennas. Digital modes are possible but have not reached momentum yet.
Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum, in a one-to-many model. Broadcasting began with AM radio, which came into popular use around 1920 with the spread of vacuum tube radio transmitters and receivers. Before this, most implementations of electronic communication were one-to-one, with the message intended for a single recipient. The term broadcasting evolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about. It was later adopted for describing the widespread distribution of information by printed materials or by telegraph. Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898.
Radio broadcasting is the broadcasting of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radio station, while in satellite radio the radio waves are broadcast by a satellite in Earth orbit. To receive the content the listener must have a broadcast radio receiver (radio). Stations are often affiliated with a radio network that provides content in a common radio format, either in broadcast syndication or simulcast, or both. Radio stations broadcast with several different types of modulation: AM radio stations transmit in AM, FM radio stations transmit in FM, which are older analog audio standards, while newer digital radio stations transmit in several digital audio standards: DAB, HD radio, DRM. Television broadcasting is a separate service that also uses radio frequencies to broadcast television (video) signals.
Terrestrial television or over-the-air television (OTA) is a type of television broadcasting in which the content is transmitted 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, 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 bands. Since radio waves in these bands travel by line of sight, reception is generally limited by the visual horizon to distances of 64–97 kilometres (40–60 mi), although under better conditions and with tropospheric ducting, signals can sometimes be received hundreds of kilometers distant.
A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broadcast. There is no physical difference between a carrier and a subcarrier; the "sub" implies that it has been derived from a carrier, which has been amplitude modulated by a steady signal and has a constant frequency relation to it.
Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services.
Second audio program (SAP), also known as secondary audio programming, is an auxiliary audio channel for analog television that can be broadcast or transmitted both over-the-air and by cable television. Used mostly for audio description or other languages, SAP is part of the multichannel television sound (MTS) standard originally set by the National Television Systems Committee (NTSC) in 1984 in the United States. The NTSC video format and MTS are also used in Canada and Mexico.
A tuner is a subsystem that receives radio frequency (RF) transmissions, such as FM broadcasting, and converts the selected carrier frequency and its associated bandwidth into a fixed frequency that is suitable for further processing, usually because a lower frequency is used on the output. Broadcast FM/AM transmissions usually feed this intermediate frequency (IF) directly into a demodulator that converts the radio signal into audio-frequency signals that can be fed into an amplifier to drive a loudspeaker.
FM broadcasting is a method of radio broadcasting that uses frequency modulation (FM) of the radio broadcast carrier wave. Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to transmit high-fidelity sound over broadcast radio. FM broadcasting offers higher fidelity—more accurate reproduction of the original program sound—than other broadcasting techniques, such as AM broadcasting. It is also less susceptible to common forms of interference, having less static and popping sounds than are often heard on AM. Therefore, FM is used for most broadcasts of music and general audio. FM radio stations use the very high frequency range of radio frequencies.
Subsidiary Communications Authorization (SCA) in the United States, and Subsidiary Communications Multiplex Operation (SCMO) in Canada, is a subcarrier on a radio station, allowing the station to broadcast additional services as part of its signal.
A television transmitter is a transmitter that is used for terrestrial (over-the-air) television broadcasting. It is an electronic device that radiates radio waves that carry a video signal representing moving images, along with a synchronized audio channel, which is received by television receivers belonging to a public audience, which display the image on a screen. A television transmitter, together with the broadcast studio which originates the content, is called a television station. Television transmitters must be licensed by governments, and are restricted to a certain frequency channel and power level. They transmit on frequency channels in the VHF and UHF bands. Since radio waves of these frequencies travel by line of sight, they are limited by the horizon to reception distances of 40–60 miles depending on the height of transmitter station.
A television station is a set of equipment managed by a business, organisation or other entity such as an amateur television (ATV) operator, that transmits video content and audio content via radio waves directly from a transmitter on the earth's surface to any number of tuned receivers simultaneously.
In broadcasting, digital subchannels are a method of transmitting more than one independent program stream simultaneously from the same digital radio or television station on the same radio frequency channel. This is done by using data compression techniques to reduce the size of each individual program stream, and multiplexing to combine them into a single signal. The practice is sometimes called "multicasting".
Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves. They are received by another antenna connected to a radio receiver. In addition to communication, radio is used for radar, radio navigation, remote control, remote sensing, and other applications.
In broadcasting, a transposer or translator is a device in or beyond the service area of a radio or television station transmitter that rebroadcasts signals to receivers which can’t properly receive the signals of the transmitter because of a physical obstruction. A translator receives the signals of the transmitter and rebroadcasts the signals to the area of poor reception. Sometimes the translator is also called a relay transmitter, rebroadcast transmitter or transposer. Since translators are used to cover a small shadowed area, their output powers are usually lower than that of the radio or television station transmitters feeding them.
UHF television broadcasting is the use of ultra high frequency (UHF) radio for over-the-air transmission of television signals. UHF frequencies are used for both analog and digital television broadcasts. UHF channels are typically given higher channel numbers, like the US arrangement with VHF channels (initially) 1 to 13, and UHF channels (initially) numbered 14 to 83. Compared with an equivalent VHF television transmitter, to cover the same geographic area with a UHF transmitter requires a higher effective radiated power, implying a more powerful transmitter or a more complex antenna. However, the additional channels allow more broadcasters in a given region without causing objectionable mutual interference.
An unlicensed FM station (often run by an amateur radio operator) that manages to occupy a commercial or state-run FM band is an example of a pirate or "bootleg" radio station