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Frequency Channel
In broadcasting, a channel or frequency channel is a designated radio frequency (or, equivalently, wavelength), assigned by a competent frequency assignment authority for the operation of a particular radio station, television station or television channel. See also *Frequency allocation, ITU RR, article 1.17 *Frequency assignment, ITU RR, article 1.18 * Broadcast law *Television channel frequencies The following tables show the frequencies assigned to analog broadcast television channels in various regions of the world, along with the ITU letter designator for the transmission system used. The frequencies shown are for the channel limits an ... References International Telecommunication Union (ITU) Broadcasting {{Broadcast-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadcasting
Broadcasting is the data distribution, distribution of sound, audio audiovisual content to dispersed audiences via a electronic medium (communication), mass communications medium, typically one using the electromagnetic spectrum (radio waves), in a :wikt:one-to-many, 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 radio receiver, receivers. Before this, most implementations of electronic communication (early radio, telephone, and telegraph) were wikt:one-to-one, 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 ... [...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] |
Wavelength
In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves), phase'' on the wave, such as two adjacent crests, troughs, or zero crossings. Wavelength is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The multiplicative inverse, inverse of the wavelength is called the ''spatial frequency''. Wavelength is commonly designated by the Greek letter lambda (''λ''). For a modulated wave, ''wavelength'' may refer to the carrier wavelength of the signal. The term ''wavelength'' may also apply to the repeating envelope (mathematics), envelope of modulated waves or waves formed by Interference (wave propagation), interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed phase velocity, wave speed, wavelength is inversely proportion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Assignment
Frequency assignment is the authorization of use of a particular radio frequency. In Article 1.18 of the International Telecommunication Union's (ITU) Radio Regulations (RR),ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.18, definition: ''assignment (of a radio frequency or radio frequency channel)'' the process is defined as "Authorization given by a frequency administration for a radio station to use a radio frequency or radio frequency channel under specified conditions". ''Frequency assignment'' is also a special term, used by national frequency administrations. For other terms see table below. See also *Radio station *Spectrum management * Frequency coordinator *Broadcast license *Cellular frequencies Cellular frequencies are the sets of frequency ranges within the ultra high frequency band that have been frequency assignment, assigned for cellular-compatible mobile devices, such as mobile phones, to connect to cellular networks.Guowang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Assignment Authority
Spectrum management is the process of regulating the use of radio frequency, radio frequencies to promote efficient use and gain a net social benefit.Martin Cave, Chris Doyle, William Webb, ''Modern Spectrum Management'', Cambridge University Press, 2007 The term ''radio spectrum'' typically refers to the full frequency range from 1 hertz, Hz to 3000 hertz, GHz (3 hertz, THz) that may be used for wireless communication. Increasing demand for services such as mobile telephones and many others has required changes in the philosophy of spectrum management. Demand for wireless broadband has soared due to technological innovation, such as 3G and 4G mobile services, and the rapid expansion of wireless internet services. Since the 1930s, spectrum was assigned through administrative licensing. Limited by technology, signal interference was once considered as a major problem of spectrum use. Therefore, exclusive licensing was established to protect licensees' signals. This forme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Broadcasting
Radio broadcasting is the broadcasting of audio signal, 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 Radio receiver, 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. The code, encoding of a radio broadcast depends on whether it uses an analog signal, analog or digital signal. Analog radio broadcasts use one of two types of radio wave modulation: amplitude modulation for AM radio, or frequency modulation for FM radio. Newer, digital radio stations transmit in several different digital audio standards, such as DAB (Digital Audio Broadcas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television 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 Television sets, receivers simultaneously. Overview The ''Fernsehsender Paul Nipkow'' (''TV Station Paul Nipkow'') in Berlin, Germany, was the first regular television service in the world. It was on the air from 22 March 1935, until it was shut down in 1944. The station was named after Paul Gottlieb Nipkow, the inventor of the Nipkow disk. Most often the term "television station" refers to a station which broadcasts structured content to an audience or it refers to the organization that operates the station. A terrestrial television transmission can occur via analog television signals or, more recently, via digital television signals. Television stations are differentiated from cable television or other video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Allocation
Frequency allocation (or spectrum allocation) is the part of spectrum management dealing with the designation and regulation of the electromagnetic spectrum into frequency bands, normally done by governments in most countries. Because radio propagation does not stop at national boundaries, governments have sought to harmonise the allocation of RF bands and their standardization. ITU definition The International Telecommunication Union defines frequency allocation as being of "a given frequency band for the purpose of its use by one or more terrestrial or space radiocommunication services or the radio astronomy service under specified conditions".ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.16, definition: allocation (of a frequency band). ''Frequency allocation'' is also a special term, used in national frequency administration. Other terms are: Bodies Several bodies set standards for frequency allocation, including: * International Telecomm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Assignment
Frequency assignment is the authorization of use of a particular radio frequency. In Article 1.18 of the International Telecommunication Union's (ITU) Radio Regulations (RR),ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.18, definition: ''assignment (of a radio frequency or radio frequency channel)'' the process is defined as "Authorization given by a frequency administration for a radio station to use a radio frequency or radio frequency channel under specified conditions". ''Frequency assignment'' is also a special term, used by national frequency administrations. For other terms see table below. See also *Radio station *Spectrum management * Frequency coordinator *Broadcast license *Cellular frequencies Cellular frequencies are the sets of frequency ranges within the ultra high frequency band that have been frequency assignment, assigned for cellular-compatible mobile devices, such as mobile phones, to connect to cellular networks.Guowang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television Channel Frequencies
The following tables show the frequencies assigned to analog broadcast television channels in various regions of the world, along with the ITU letter designator for the transmission system used. The frequencies shown are for the channel limits and for the analog video and audio carriers. The channel itself usually occupies 6, 7 or 8 megahertz of bandwidth depending on the television transmission system in use. For example, North American channel 1 occupies the spectrum from 44 to 50 MHz. See Broadcast television systems for a table of signal characteristics, including bandwidth, by ITU letter designator. Analog television broadcasts have been phased out in most regions, having been replaced by digital television broadcasts. International normalization for analog TV systems International broadcasting television frequencies are divided in two part of the spectrum; the Very high frequency or "VHF" band and the Ultra high frequency or "UHF" band. VHF Americas (most coun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
