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Band III
Band III is the name of the range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum from 174 to 240 megahertz (MHz). It is primarily used for radio and television broadcasting. It is also called high-band VHF, in contrast to Bands I and II. Broadcast Television North America The band is subdivided into seven channels for television broadcasting, each occupying 6 MHz. Europe European Band III allocations vary from country to country, with channel widths of 7 or 8 MHz. The standard channel allocations for European countries that use System B with 7 MHz channel spacing are as follows: The Irish (8 MHz) system is shown below. Oceania Australia has allocated 8 channels in Band III for digital television, each with 7 MHz bandwidth. Russia and other former members of OIRT Russian analog television is transmitted using System D with 8 MHz channel bandwidth. Radio The band came into use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper limit of audio frequencies that humans can hear (though these are not electromagnetic) and the lower limit of infrared frequencies, and also encompasses the microwave range. These are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves, so they are used in radio technology, among other uses. Different sources specify different upper and lower bounds for the frequency range. Electric current Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. * Energy from RF currents in conduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monochrome
A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, monochromatic light refers to electromagnetic radiation that contains a narrow band of wavelengths, which is a distinct concept. Application Of an image, the term monochrome is usually taken to mean the same as black and white or, more likely, grayscale, but may also be used to refer to other combinations containing only tones of a single color, such as green-and-white or green-and-red. It may also refer to sepia displaying tones from light tan to dark brown or cyanotype ("blueprint") images, and early photographic methods such as daguerreotypes, ambrotypes, and tintypes, each of which may be used to produce a monochromatic image. In computing, monochrome has two meanings: * it may mean having only one color which is either on or off (a ... [...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, instantaneous phase and frequency, 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 Noise (video), snowy and subject to interference. In contrast, picture quality from a digital television (DTV) signal remains good until the signal level drops below digital cliff, 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 requ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NTSC
NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170. In 1953, a second NTSC standard was adopted, which allowed for color television broadcast compatible with the existing stock of black-and-white receivers. It is one of three major color formats for analog television, the others being PAL and SECAM. ''NTSC color'' is usually associated with the System M; this combination is sometimes called NTSC II. The only other broadcast television system to use NTSC color was the System J. Brazil used System M with PAL color. Vietnam, Cambodia and Laos used System M with SECAM color – Vietnam later started using PAL in the early 1990s. The NTSC/System M standard was used in most of the Americas (except Argentina, Brazil, Paraguay, and Uruguay), Myanmar, South Korea, Taiwan, Philippines, Japan, and some Pacific Isl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band I
Band I is a range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum. The first time there was defined "for simplicity" in Annex 1 of "Final acts of the European Broadcasting Conference in the VHF and UHF bands - Stockholm, 1961". Band I ranges from 47 to 68 MHz for the European Broadcasting Area, and from 54 to 88 MHz for the Americas and it is primarily used for television broadcasting in compliance with ITU Radio Regulations (article 1.38). With the transition to digital TV, most Band I transmitters have already been switched off. Television broadcasting usage Channel spacings vary from country to country, with spacings of 6, 7 and 8 MHz being common. In the UK, Band I was originally used by the BBC for monochrome 405-line television; likewise, the French former 455-line (1937–1939) then 441-line (1943–1956) transmitter on the Eiffel Tower in Paris, and some stations of the French monochrome 819-line system used Band I. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Television
Digital television (DTV) is the transmission of television signals using Digital signal, 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 (4:3) of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same Bandwidth (signal processing), bandwidth as a single analog channel, and provides many new features that analog television cannot. A digital television transition, transition from analog to digital broadcasting began around 2000. Different digital television broadcasting st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of North American Broadcast Station Classes
This is a list of broadcast station classes applicable in much of North America under international agreements between the United States, Canada and Mexico. Effective radiated power (ERP) and height above average terrain (HAAT) are listed unless otherwise noted. All radio and television stations within of the US-Canada or US-Mexico border must get approval by both the domestic and foreign agency. These agencies are Industry Canada/ Canadian Radio-television and Telecommunications Commission (CRTC) in Canada, the Federal Communications Commission (FCC) in the US, and the Federal Telecommunications Institute (IFT) in Mexico. AM Station class descriptions All domestic (United States) AM stations are classified as A, B, C, or D. * A (formerly I) — clear-channel stations — 10 kW to 50 kW, 24 hours. **Class A stations are only protected within a radius of the transmitter site. **The old Class I was divided into three: Class I-A, I-B and I-N. NARBA disting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilowatt
The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work (physics), energy transfer. The watt is named in honor of James Watt (1736–1819), an 18th-century Scottish people, Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own Watt steam engine, steam engine in 1776, which became fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one meter per second against a constant opposing force of one Newton (unit), newton, the rate at which Work (physics), work is done is one watt. \mathrm. In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Audio Broadcasting
Digital Audio Broadcasting (DAB) is a digital radio international standard, standard for broadcasting digital audio radio services in many countries around the world, defined, supported, marketed and promoted by the WorldDAB organisation. The standard is dominant in Europe and is also used in Australia, and in parts of Africa and as of 2025, countries using DAB/DMB, 55 countries are actively running DAB broadcasts as an alternative platform to analogue FM. DAB was the result of a European research project and first publicly rolled out in 1995, with consumer-grade DAB Radio receiver, receivers appearing at the start of this millennium. Initially it was expected in many countries that existing FM broadcasting, FM services would switch over to DAB, although the take-up of DAB has been much slower than expected. In 2023, Norway became the first country to have implemented a national FM radio switch-off, with others to follow in the next years, Switzerland and the United Kingdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DVB-T
DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in February 1998. This system transmits compressed digital audio, digital video and other data in an MPEG transport stream, using coded orthogonal frequency-division multiplexing (COFDM or OFDM) modulation. It is also the format widely used worldwide (including North America) for Electronic News Gathering for transmission of video and audio from a mobile newsgathering vehicle to a central receive point. It is also used in the US by amateur television operators. Basics Rather than carrying one data carrier on a single radio frequency (RF) channel, COFDM works by splitting the digital data stream into a large number of slower digital streams, each of which digitally modulates a set of closely spaced adjacent sub-carrier frequencies. In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
576i
576i is a standard-definition television, standard-definition digital video mode, originally used for Digitization, digitizing 625 lines, 625 line Analog television, analogue television in most countries of the world where the utility frequency for electric power distribution is 50 Hz. Because of its close association with the legacy colour encoding systems, it is often referred to as PAL#PAL region, PAL, PAL/SECAM or SECAM when compared to its 60 Hz (typically, see PAL-M) NTSC-colour-encoded counterpart, 480i. The ''576'' identifies a vertical resolution of 576 lines, and the ''i'' identifies it as an Interlaced video, interlaced resolution. The Refresh rate, field rate, which is 50 Hertz, Hz, is sometimes included when identifying the video mode, i.e. 576i50; another notation, endorsed by both the International Telecommunication Union in Rec. 601, BT.601 and SMPTE in SMPTE 259M, includes the frame rate, as in 576i/25. Operation In analogue television, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
