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Information about Virtual Channel

For the SDRAM technology, see VC-RAM.


In telecommunications, a logical channel number (LCN), also known as virtual channel in North America, is a channel designation which differs from the actual radio channel or frequency on which the signal travels.

This is most often applied to television, where digital TV (DTV) channels are in-band adjacent-channel to analog ones. Channel 8 might use channel 32 for its ATSC or DVB transmission, but a virtual channel map or virtual channel table (VCT) allows viewers to tune to channel 8 on a digital set anyhow. DTV tuners typically scan all channels for this information while they are turned "off", and store it in memory for instant access later on.

Because DTV can carry multiple programs simultaneously, virtual channels also map out subchannels. Typically in the United States and Canada, the main programme is on channel 8.1 (or 8-1), in the example for channel 8. Other programmes are on 8.2, 8.3, and so forth up to 99, with data channels from 100 to 999. In this case, 8 is the "major channel", and 1, 2, or 3 is the subchannel. There is no practical difference between a dot and a dash, though the dot looks familiar to FM listeners, and avoids confusion with a range (for example, 2-4 is 2.4, not 2 to 4). Australia has a slightly different format due to the smaller number of main channels and doesn't require a dot or a dash (for example, 22 is a digital subchannel of 2, ABC TV), while the use of multiplexes throughout Europe leads to subchannels being treated like main channels (e.g. in the United Kingdom, ITV2 has its own channel number, 6, distinct from ITV1's channel number 3)

Virtual channels are also used on direct broadcast satellites, such as Dish Network, DirecTV, and Astra. Rather than a few dozen channels with a few subchannels each, these services map to a range of hundreds of individually numbered channels. Cable TV also does this on digital cable, as does satellite radio.

Digital radio also uses channels and subchannels, but only for DAB. The IBOC systems (iBiquity and Digital Radio Mondiale) do not currently use any virtual channels, mainly because they are lucky to fit anything digital at all on an analog carrier. As IBOC progresses and bandwidth improves due to new technology and the discontinuation of stereo subcarriers (and later analog althogether), virtual channels may take hold there as well.

In Computer networks, a virtual channel is synonymous to a virtual circuit or virtual connection.

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Virtual Channel Random Access Memory (VC-RAM in short, other names such as VC-SDRAM, VCSDRAM, VCDRAM, or VCM) was a proprietary type of SDRAM produced by NEC, but released as an open standard, with no licensing fees.
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Telecommunication is the transmission of signals over a distance for the purpose of communication. In modern times, this process typically involves the sending of electromagnetic waves by electronic transmitters, but in earlier times telecommunication may have involved the use of
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North America is a continent [1] in the Earth's northern hemisphere and (chiefly) western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the south and west
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Channel, in communications (sometimes called communications channel), refers to the used to convey information from a sender (or transmitter) to a receiver.

Overview

A Channel can take many forms.
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Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space.
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FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. A sequel, titled Amplitude was released in 2003.
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In telecommunication, signalling (UK spelling) or signaling (US spelling) has the following meanings:
  • The use of signals for controlling communications.

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Television (often abbreviated to TV, T.V., or more recently, tv; sometimes called telly, the tube, boob tube, or idiot box in British English) is a widely used telecommunication system for broadcasting and receiving moving pictures
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Digital television (DTV) is a telecommunication system for broadcasting and receiving moving pictures and sound by means of digital signals, in contrast to analog signals used by analog (traditional) TV.
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IBAC is a method of placing digital TV stations on channels in the existing analog TV bands. While this technique can also be applied to other radio frequency bands, no country has yet done so.

See also

  • Digital subchannels
  • In-band on-channel (IBOC)

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ATSC Standards document a digital television format which will replace (in the United States) the analog NTSC television system[1] (NTSC is used mostly in North America and Japan). It was developed by the Advanced Television Systems Committee.
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DVB, short for Digital Video Broadcasting, is a suite of internationally accepted open standards for digital television. DVB standards are maintained by the DVB Project, an industry consortium with more than 270 members, and they are published by a
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In telecommunications, transmission is the forwarding of signal traffic over distances that are too great to be simply connected by a twisted pair wires. Techniques available now may be microwave link, satellite link, coaxial cable or fibre optic cable.
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Tuner may refer to:
  • Antenna tuner, a device to adjust the resonance frequency of an antenna or transmission line
  • Tuner (electronics) a module or device which converts low-amplitude radio-frequency signals into a form suitable for processing by further modules or

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Motto
"In God We Trust"   (since 1956)
"E Pluribus Unum"   ("From Many, One"; Latin, traditional)
Anthem
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This page is currently protected from editing until disputes have been resolved.
Protection is not an endorsement of the current [ version] ([ protection log]).
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FM broadcasting is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation (FM) to provide high-fidelity sound over broadcast radio.
Main article: frequency modulation

Broadcast bands


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Anthem
Advance Australia Fair [1]


Capital Canberra

Largest city Sydney
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Motto
"Dieu et mon droit" [2]   (French)
"God and my right"
Anthem
"God Save the Queen" [3]
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Availability
Terrestrial
Freeview Channel 6
Channel 31 (+1)
Satellite
Sky Digital Channel 118
Channel 184 (+1)
SES Astra 10758V, 22.0, 5/6 (manual tuning)
Cable
Virgin Media
(ex NTL) Channel 114
Virgin Media
(ex Telewest) Channel 113
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ITV1

Based in London (playout)
Various locations throughout England and Wales
Broadcast area England,
Southern Scotland,
Wales,
Isle of Man and Channel Islands
Launched 11 August 2001

One of ITV1's idents, first aired in November 2006

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Direct broadcast satellite (DBS) is a term used to refer to satellite television broadcasts intended for home reception, also referred to as direct-to-home signals.
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DISH Network, Inc.

Subsidiary
Founded 1996
Headquarters Meridian, Colorado, USA

Industry Telecommunication
Products Direct broadcast satellite
Employees (EchoStar 20,000)
Website dishnetwork.
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DirecTV, Inc.

Subsidiary of The DirecTV Group
Founded 1994
Headquarters El Segundo, CA, USA

Key people Rupert Murdoch, Chairman
Chase Carey, President & CEO
Industry Telecommunication
Products Direct broadcast satellite
Revenue US$14.
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Société Européenne des Satellites-Astra

Privately-owned subsidiary
Founded 1985
Headquarters Betzdorf, Luxembourg

Industry Telecommunications
Products Satellite Services
Revenue € ? billion (2006)
Operating income € ?
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cable television into the house.]]

Cable television is a system of providing cocoy television to consumers via radio frequency signals transmitted to televisions through fixed optical fibers or coaxial cables as opposed to the over-the-air method used in traditional
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Digital cable is a type of cable television distribution using digital video compression. The technology was developed by Motorola.

Uses

Digital cable is used by cable distributors to increase the variety of programming available on their networks, using video compression
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A satellite radio or subscription radio (SR) is a digital radio signal that is broadcast by a communications satellite, which covers a much wider geographical range than terrestrial radio signals.
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Digital radio describes radio technologies which carry information as a digital signal. The topic covers both broadcasting by radio and two-way communications. The acronym DAB has been used to identify the generic technology of digital audio broadcasting, although now it has become
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