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Encyclopedia > Broadcast television systems

There are several broadcast television systems in use in the world today. An analogue television system includes several components: a set of technical parameters for the broadcast signal, a system for encoding color, and possibly a system for encoding multi-channel audio. In digital television, all of these elements are combined in a single digital transmission system. Analog television encodes picture information by varying the voltages and/or frequency of the signal. ... Look up encoding in Wiktionary, the free dictionary. ... 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. DTV uses digital modulation data, which is digitally compressed and requires decoding by a specially designed television set, or a...

Contents

Analogue television systems

All analogue television systems began life in monochrome. Each country, faced with local political, technical, and economic issues, adopted a color system which was effectively grafted on to an existing monochrome system, using gaps in the video spectrum (explained below) to allow the color information to fit in the channels allotted. In theory, any color system could be used with any monochrome video system, but in practice some of the original monochrome systems proved impractical to adapt to color and were abandoned when the switch to color broadcasting was made. All countries use one of three color systems: NTSC, PAL, or SECAM. The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... Television encoding systems by nation. ... SECAM, also written SÉCAM (Séquentiel couleur à mémoire, French for Sequential Color with Memory), is an analog color television system first used in France. ...


Frames

Ignoring color, all television systems work in essentially the same manner. The monochrome image seen by a camera (now, the luminance component of a color image) is divided into horizontal scan lines, some number of which make up a single image or frame. A monochrome image is theoretically continuous, and thus unlimited in horizontal resolution, but to make television practical a limit had to be placed on the bandwidth of the television signal, which puts an ultimate limit on the horizontal resolution possible. When color was introduced, this limit of necessity became fixed. All analog television systems are interlaced; that is to say, alternate rows of the frame are transmitted in sequence, followed by the remaining rows in their sequence. Each half of the frame is called a field, and the rate at which fields are transmitted is one of the fundamental parameters of a video system. Usually it is closely related to the frequency at which the electric power grid operates, to avoid the appearance of a flicker resulting from the beat between the television screen and nearby electric lights. Digital, or 'fixed pixel', displays are all progressive scan and must deinterlace an interlaced source. Use of inexpensive deinterlacing hardware is a typical difference between lower- vs. higher-priced flat panel displays (PDP, LCD, etc.). As applied to analog television signals, two different words are used, luminance and luma, meaning two different things. ... This article does not cite any references or sources. ... Interlacing is a method of displaying images on a raster-scanned display device, such as a cathode ray tube (CRT). ... 11kV/400V-230V transformer in an older suburb of Wellington, New Zealand Electricity distribution is the penultimate stage in the delivery (before retail) of electricity to end users. ... In acoustics, a beat is an interference between two sounds of slightly different frequencies, perceived as periodic variations in volume whose rate is the difference between the two frequencies. ...


All movies and other filmed material shot at 24 frames per second must be transferred to video frame rates in order to prevent severe motion jitter effects. Techniques known as '2:2:2:2:2:2:2:2:2:2:2:3 pulldown' (for 25 fps PAL) and '3:2 pulldown' (for 30 fps NTSC) are used to match the film frames to the video frames without speeding up the play back. (See Telecine.) Film is a term that encompasses individual motion pictures, the field of film as an art form, and the motion picture industry. ... It has been suggested that multiple sections of 24p be merged into this article or section. ...


Viewing technology

Since television was originally implemented using cathode-ray tubes (CRT), the physics of these devices necessarily intrudes on the format of the video they can be used to display. The image on a CRT is painted by a moving beam of electrons which hits a phosphor coating on the front of the tube. This electron beam is steered by a magnetic field generated by powerful electromagnets close to the source of the electron beam. The cathode ray tube or CRT, invented by Karl Ferdinand Braun, is the display device used in most computer displays, video monitors, televisions and oscilloscopes. ... Green screen A phosphor is a substance that exhibits the phenomenon of phosphorescence (sustained glowing after exposure to light or energised particles such as electrons). ... An electromagnet is a type of magnet in which the magnetic field is produced by a flow of electric current. ...


In order to reorient this magnetic steering mechanism, a certain amount of time is required due to the inductance of the magnets; the greater the change, the greater the time it takes for the electron beam to settle in the new spot. Inductance (or electric inductance) is a measure of the amount of magnetic flux produced for a given electric current. ...


For this reason, it is necessary to shut off the electron beam (corresponding to a video signal of zero luminance) during the time it takes to reorient the beam from the end of one line to the beginning of the next (horizontal retrace) and from the bottom of the screen to the top (vertical retrace or vertical blanking interval). The horizontal retrace is accounted for in the time allotted to each scan line, but the vertical retrace is accounted for as phantom lines which are never displayed but which are included in the number of lines per frame defined for each video system. Since the electron beam must be turned off in any case, the result is gaps in the television signal, which can be used to transmit other information, such as test signals or color identification signals. The vertical blanking interval (VBI) is an interval in a television or VDU signal that temporarily suspends transmission of the signal for the electron gun to move back up to the first line of the television screen to trace the next screen field. ...


The temporal gaps translate into a comb-like frequency spectrum for the signal, where the teeth are spaced at line frequency and concentrate most of the energy; the space between the teeth can be used to insert a color subcarrier. Familiar concepts associated with a frequency are colors, musical notes, radio/TV channels, and even the regular rotation of the earth. ...


Hidden signalling

Broadcasters later developed mechanisms to transmit digital information on the phantom lines, used mostly for teletext and closed captioning: A BBC Ceefax page from January 9, 2007. ... A commonly-used symbol indicating that a program or movie is closed-captioned. ...

  • PAL-Plus uses a hidden signalling scheme to indicate if it exists, and if so what operational mode it is in.
  • NTSC has an anti-ghosting signal that is inserted on a non-visible scan line.
  • Teletext uses hidden signalling to transmit information pages.
  • NTSC Closed Captioning signalling uses signalling that is nearly identical to teletext signalling.

PALplus is an extension of the PAL analogue broadcasting system for transmitting 16:9 programs without sacrificing vertical resolution. ... In television technology, widescreen signaling (WSS) is a digital stream embedded in the TV signal describing qualities of the broadcast, in particular the intended aspect ratio of the image. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... Ghost-canceling reference, or GCR, is a special sub-signal on a television channel that receivers can use to attenuate the ghosting effect of a television signal split into multiple paths between transmitter and receiver. ... A BBC Ceefax page from January 9, 2007. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... A commonly-used symbol indicating that a program or movie is closed-captioned. ... A BBC Ceefax page from January 9, 2007. ...

Overscan

Television images are unique in that they must incorporate regions of the picture with reasonable-quality content, that will never be seen by some viewers.


For more information, see overscan in television. This concept is analogous to producing widescreen content that will be cropped for some viewers who don't have widescreen. Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ...


Interlacing

Main article: Interlace

In the PAL standard the odd (upper) field is drawn first and the even (lower) field second. In the NTSC standard, the even (lower) field is drawn first and the odd (upper) field second opposite to PAL. For the method of incrementally displaying raster graphics, see Interlace (bitmaps). ... Television encoding systems by nation. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ...


Image polarity

Another parameter of analogue television systems, minor by comparison, is the choice of whether vision modulation is positive or negative. In positive modulation, the maximum luminance value is represented by the maximum electrical signal; in negative modulation, the maximum luminance value is represented by a zero electrical signal. Most video systems were defined to use negative modulation to reduce the appearance of noise, on the theory that dark spots in the image would be less noticeable than bright white spots in the image, given a particularly common sort of noise. In telecommunications, modulation is the process of varying a periodic waveform, i. ...


Modulation

Given all of these parameters, the result is a mostly-continuous analogue signal which can be modulated onto a radio-frequency carrier and transmitted through an antenna. All analogue television systems use vestigial sideband modulation, a form of amplitude modulation in which the lower sideband is incompletely suppressed. This provides a small guard band between the actual video carrier and the bottom frequency in the channel, which helps to reduce interference between transmitters on adjoining channels at a receiver which receives strong signals from both. At the time television was developed, the vestigial sideband was easier to accomplish than true single-sideband modulation; with today's technology, there is no reason for it except to be compatible with existing technology. Single-sideband modulation (SSB) is a refinement of the technique of amplitude modulation designed to be more efficient in its use of electrical power and bandwidth. ... Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. ... Single-sideband modulation (SSB) is a refinement of the technique of amplitude modulation designed to be more efficient in its use of electrical power and bandwidth. ...


Audio

In analogue television, the sound portion of a broadcast is invariably modulated separately from the video. Most commonly, the audio and video are combined at the transmitter before being presented to the antenna, but in some cases separate aural and visual antennas can be used. In almost all cases, standard wideband frequency modulation is used for the standard monaural audio; the exception is systems used by France, which are AM. Stereo, or more generally multi-channel, audio is encoded using a number of schemes which (except in the French systems) are independent of the video system. The principal systems are NICAM, which uses a digital audio encoding; double-FM (known under a variety of names, notably Zweikanalton, A2 Stereo, West German Stereo, German Stereo or IGR Stereo), in which case each audio channel is separately modulated in FM and added to the broadcast signal; and BTSC (also known as MTS), which multiplexes additional audio channels on the existing FM audio carrier. All three systems are compatible with monaural FM audio, but only NICAM may be used with the French AM audio systems. Frequency modulation (FM) is a form of modulation that represents information as variations in the instantaneous frequency of a carrier wave. ... Monaural (often shortened to mono) sound reproduction is single-channel. ... NICAM (known also as NICAM 728, after the 728 kbit/s bitstream it is sent over), Near Instantaneous Companded Audio Multiplex, is a format for digital sound on analogue television transmissions. ... Zweikanalton (two channel sound) is a television sound transmission system used in Germany and other countries. ... Multichannel television sound, better known as MTS (often still as BTSC, for the Broadcast Television Systems Committee that created it), is the method of encoding three additional channels of audio into an NTSC-format audio carrier. ... MTS may stand for: Machine and Tractor Station, in the Soviet Union Manitoba Telecom Services Manual Tone Shift Mercato dei Titoli di Stato, colloquially known as the Telematico, the main Eurozone government bond electronic trading system Metre-tonne-second system of units, more commonly written mts Michigan Terminal System, a... NICAM (known also as NICAM 728, after the 728 kbit/s bitstream it is sent over), Near Instantaneous Companded Audio Multiplex, is a format for digital sound on analogue television transmissions. ...


Evolution

For historical reasons, many countries use a different video system on UHF than they do on the VHF bands. In a few countries, most notably the United Kingdom, television broadcasting on VHF has been entirely shut down. Note that the British System A, unlike all the other systems, suppressed the upper sideband rather than the lower — befitting its status as the oldest operating television system to survive into the colour era. System A was tested with all three colour systems, and production equipment was designed and ready to be built; System A might have survived, as NTSC-A, had the British government not decided to harmonize with the rest of Europe on a 625-line video standard, implemented in Britain as PAL-I on UHF only. This article is about the radio frequency. ... Very high frequency (VHF) is the radio frequency range from 30 MHz to 300 MHz. ... The 405-line monochrome analogue television broadcasting system was the first electronic television system to be used in regular broadcasting. ...


The French System E was a post-war effort to advance France's standing in television technology. Its 819 scan lines were almost high definition even by today's standards. Like the British system A it was VHF only and remained black & white until its shutdown in the 1980s. It was tested with SECAM in the early stages, but later the decision was made to adopt colour in 625 lines. Thus France adopted system L on UHF only and abandoned system E. Historically, the term high-definition television was first used to refer to television standards developed in the 1930s to replace early experimental systems with as few as 12 lines. ... This article does not cite any references or sources. ...


In some urban areas of Germany, notably in and around Berlin and some other major cities, all analogue TV broadcasting has been shut down in 20032005 in favour of reallocating the frequencies to digital broadcasting in the DVB-T standard. See http://www.ueberallfernsehen.de/ for a map of coverage areas and near-future switchovers. Analogue signals are still on air in the non-coloured areas of the map. The rest of the country is scheduled to follow suit by 2010. Many other countries are planning a shutdown of analogue broadcasting, and as of 2007 a few smaller countries have already done so. (See "Analogue switch-off" in the digital television article for more information.) This article is about the capital of Germany. ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... DVB-T stands for Digital Video Broadcasting - Terrestrial and it is the DVB European consortium standard for the broadcast transmission of digital terrestrial television. ... This article does not cite any references or sources. ... 2007 is a common year starting on Monday of the Gregorian calendar. ... 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. DTV uses digital modulation data, which is digitally compressed and requires decoding by a specially designed television set, or a... 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. DTV uses digital modulation data, which is digitally compressed and requires decoding by a specially designed television set, or a...


List of analog television systems

Pre World War II systems

A number of experimental and broadcast pre WW2 systems were tested. The first ones were mechanical based and of very low resolution, some times with no sound. Latter TV systems were electronic. A number of experimental and broadcast pre World War II systems were tested. ...

  • The UK 405 line system was the first to have an allocated ITU System Letter Designation.

ITU identification scheme

On an international conference in Stockholm in 1961, the International Telecommunications Union has defined an identification scheme for broadcast television systems. Each monochrome system is assigned a letter designation (A-M); in combination with a color system (NTSC, PAL, SECAM), this completely specifies all of the monaural analogue television systems in the world (for example, PAL-B, NTSC-M, etc). Nickname: Location of Stockholm in northern Europe Coordinates: Country Sweden Municipality Stockholm Municipality County Stockholm Province Södermanland and Uppland Charter 13th Century Population (April 2007)  - City 782,885  - Density 4,160/km² (10,774. ... The International Telecommunication Union (ITU) is an international organization established to standardize and regulate international radio and telecommunications. ...


The following table gives the principal characteristics of each system. Most values are measured in MHz.

World television systems
System Lines  Frame rate Channel bandwidth (in MHz) Visual bandwidth (in MHz) Sound offset Vestigial sideband Vision mod. Sound mod.
A 405 25 5 3 −3.5 0.75 Pos. AM
B 625 25 7 5 +5.5 0.75 Neg. FM
C 625 25 7 5 +5.5 0.75 Pos. AM
D 625 25 8 6 +6.5 0.75 Neg. FM
E 819 25 14 10 ±11.15 2.00 Pos. AM
F 819 25 7 5 +5.5 0.75 Pos.
AM
G 625 25 8 5 +5.5 0.75 Neg. FM
H 625 25 8 5 +5.5 1.25 Neg. FM
I 625 25 8 5.5 +5.9996 1.25 Neg. FM
J 525 29.97 6 4.2 +4.5 0.75 Neg. FM
K 625 25 8 6 +6.5 0.75 Neg. FM
K' 625 25 8 6 +6.5 1.25 Neg. FM
L 625 25 8 6 +6.5 1.25 Pos. AM
M 525 29.97 6 4.2 +4.5 0.75 Neg. FM
N 625 25 6 4.2 +4.5 0.75 Neg. FM

General notes: The following tables show the frequencies assigned to broadcast television channels in various regions of the world, along with the ITU letter designator for the system used. ... 405 line is the name of a monochrome analogue television broadcasting system in operation in the UK between 1936 and 1985, and also used for some time in Ireland and Hong Kong. ... 405 line is the name of a monochrome analogue television broadcasting system in operation in the UK between 1936 and 1985, and also used for some time in Ireland and Hong Kong. ... Historically, the term high-definition television was first used to refer to television standards developed in the 1930s to replace early experimental systems with as few as 12 lines. ... Historically, the term high-definition television was first used to refer to television standards developed in the 1930s to replace early experimental systems with as few as 12 lines. ... Historically, the term high-definition television was first used to refer to television standards developed in the 1930s to replace early experimental systems with as few as 12 lines. ... Historically, the term high-definition television was first used to refer to television standards developed in the 1930s to replace early experimental systems with as few as 12 lines. ...

  • TV systems no longer in use are shown in grey text.
  • The upper (odd) field is drawn first.

Notes by system:

A
Old United Kingdom VHF system (black-and-white only), and the first electronic TV system, introduced in 1936. Vestigal sideband filtering was introduced in 1949.
B
VHF only in most countries (see systems G and H); VHF and UHF in Australia.
C
Old VHF system; used only in Belgium, as a compromise between Systems B and L.
D
Used on VHF only in most countries (see system K for UHF). Used in the People's Republic of China on both VHF and UHF.
E
Old French VHF system; very good (near HDTV) picture quality but uneconomical use of bandwidth.
F
Old VHF system used only in Belgium and Luxembourg; allowed French 819-line programming to be broadcast on the 7-MHz VHF channels used in those countries, at a substantial cost in horizontal resolution.
G
UHF only; used in countries with system B on VHF, except Australia.
H
UHF only; used in Belgium, Luxembourg and the former Yugoslavia. Similar to System G with an 1.25 MHz vestigal sideband.
I
UK, Ireland, South Africa, Macau, and Hong Kong.
J
VHF and UHF in Japan (see system M below). Identical to system M except that a different black level of 0 IRE (unit) is used instead of 7.5 IRE.
K
UHF only; used in countries with system D on VHF, and identical to it in most respects.
K'
Used only in French overseas departments and territories.
L
Used only in France. On VHF Band 1 only, the audio is at −6.5 MHz.
M
Used in most of the Americas and Caribbean, Philippines, South Korea, Taiwan (all NTSC-M) and Brazil (PAL-M).
N
Used in Argentina, Paraguay, Uruguay (all PAL-N). Allows 625-line, 50-frame/s video to be broadcast in a 6-MHz channel, at some cost in horizontal resolution.

High-definition television (HDTV) means broadcast of television signals with a higher resolution than traditional formats (NTSC, SECAM, PAL) allow. ... Yugoslavia (Jugoslavija in the Latin alphabet, Југославија in Cyrillic; English: Land of the South Slavs) describes three political entities that existed one at a time on the Balkan Peninsula in Europe, during most of the 20th century. ... Diagram of composite video field with IRE measurements An IRE is a unit used in the measurement of composite video signals. ... The French Overseas Departments and Territories (often abbreviated DOM-TOM for départements doutre-mer, territoires doutre-mer) consist broadly of French-administered territories outside of Europe. ... World map showing the Americas CIA political map of the Americas The Americas are the lands of the Western hemisphere or New World consisting of the continents of North America[1], Central America and South America with their associated islands and regions. ... “West Indian” redirects here. ... For other meanings of PAL see PAL (disambiguation). ...

Converting from one TV system to another

Converting between different numbers of lines and different frequencies of fields/frames in video pictures is not an easy task. Perhaps the most technical challenging conversion to make is from any of the 625-line, 25-frame/s systems to system M, which has 525 lines at 29.97 frames per second. Converting between a different numbers of pixels and different frame rates in video pictures is a complex technical problem. ...


Aside from the line count being different, it's easy to see that generating 60 fields every second from a format that has only 50 fields might pose some interesting problems. Every second, an additional 10 fields must be generated seemingly from nothing. The converter has to create new frames (from the existing input) in real time.


There are several methods used to do this, depending on the desired cost and conversion quality. The simplest possible converters simply drop 100 evenly-spaced lines from every frame, and then duplicate some of those frames to make up the difference in frame rate. More complex systems include inter-field interpolation, adaptive interpolation, and phase correlation.


Digital television systems

The situation with worldwide digital television is much simpler by comparison. Most current digital television systems are based on the MPEG-2 multiplexed data stream standard, and use the MPEG-2 video codec. They differ significantly in the details of how the MPEG stream is converted into a broadcast signal, in the video format prior to encoding (or alternately, after decoding), and in the audio format. This has not prevented the creation of an international standard that includes both major systems, even though they are incompatible in almost every respect. MPEG-2 is a standard for the generic coding of moving pictures and associated audio information [1]. It is widely used around the world to specify the format of the digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. ... A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. ... The Moving Picture Experts Group or MPEG is a working group of ISO/IEC charged with the development of video and audio encoding standards. ...


The two principal digital broadcasting systems are ATSC, developed by the Advanced Television Systems Committee and adopted as a standard in the United States and Canada, and DVB-T, the Digital Video Broadcast — Terrestrial system used in most of the rest of the world. DVB-T was designed for format compatibility with existing direct broadcast satellite services in Europe (which use the DVB-S standard), and there is also a DVB-C version for cable television. While the ATSC standard also includes support for satellite and cable television systems, operators of those systems have chosen other technologies (principally DVB-S for satellite and DVB-C for cable). Japan uses a third system, closely related to DVB-T, called ISDB-T. Established in 1982, the Advanced Television Systems Committee (ATSC) is the group that developed the ATSC digital television standard for the United States, also adopted by Canada, Mexico, South Korea, and recently Honduras and is being considered by other countries. ... The Advanced Television Systems Committee (ATSC) is the group that helped to develop the new digital television standard for the United States, also adopted by Canada, Mexico and South Korea and being considered by other countries. ... DVB-T stands for Digital Video Broadcasting - Terrestrial and it is the DVB European consortium standard for the broadcast transmission of digital terrestrial television. ... DVB-T stands for Digital Video Broadcasting - Terrestrial and it is the DVB European consortium standard for the broadcast transmission of digital terrestrial television. ... 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. ... DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 300 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC... DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 300 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC... Integrated Services Digital Broadcasting (ISDB) is the digital television (DTV) and digital audio broadcasting (DAB) format. ...


ATSC

The ATSC system uses a Zenith-developed modulation called 8-VSB; as the name implies, it is a vestigial sideband technique. Essentially, analogue VSB is to regular amplitude modulation as 8-VSB is to eight-way quadrature amplitude modulation. This system was chosen specifically to provide for maximum spectral compatibility between existing analogue TV and new digital stations in the United States' already-crowded television allocations system. After demodulation and error-correction, the 8-VSB modulation supports a digital data stream of about 19.2 Mbit/s, enough for one high-definition video stream or several "standard-definition" services. Established in 1982, the Advanced Television Systems Committee (ATSC) is the group that developed the ATSC digital television standard for the United States, also adopted by Canada, Mexico, South Korea, and recently Honduras and is being considered by other countries. ... Zenith Electronics Corporation is a manufacturer of televisions in the USA. It was the inventor of the modern remote control, and it introduced HDTV in North America. ... 8VSB is the 8-level vestigial sideband modulation method adopted for ATSC standard of digital television in the USA. There are also the similar modulations 2VSB, 4VSB, and 16VSB. There has been a continuing lobby for changing the modulation for ATSC to COFDM instead, the way DVB_T is transmitted in... Quadrature amplitude modulation (QAM) is a modulation scheme which conveys data by changing (modulating) the amplitude of two carrier waves. ...


DVB-T

DVB-T uses coded orthogonal frequency division multiplexing (COFDM), which uses as many as 8000 independent carriers, each transmitting data at a comparatively low rate. This system was designed to provide superior immunity from multipath interference, and has a choice of system variants which allow data rates from 4 MBit/s up to 24 MBit/s. One U.S. broadcaster, Sinclair Broadcasting, petitioned the Federal Communications Commission to permit the use of COFDM instead of 8-VSB, on the theory that this would improve prospects for digital TV reception by households without outside antennas (a majority in the U.S.), but this request was denied. (However, one U.S. digital station, WNYE-DT in New York, was temporarily converted to COFDM modulation on an emergency basis for datacasting information to emergency services personnel in lower Manhattan in the aftermath of the September 11 terrorist attacks.) DVB-T stands for Digital Video Broadcasting - Terrestrial and it is the DVB European consortium standard for the broadcast transmission of digital terrestrial television. ... Orthogonal frequency division modulation (OFDM, also called orthogonal frequency division multiplexing) is a technique for the modulation of digital information onto an analog carrier electromagnetic (e. ... Multipath interference is a phenomenon in the physics of waves whereby a wave from a source travels to a detector via two or more paths and, under the right condition, the two (or more) components of the wave interfere. ... The Sinclair Broadcast Group (SBG) is the operator of the largest number of local television stations in the United States, with a total of 62 stations across the country in 39 small and medium markets. ... The FCCs official seal. ... New York, New York and NYC redirect here. ... Datacasting is the broadcasting of data over a wide area via radio waves. ... Manhattan is a borough of New York City, New York, USA, coterminous with New York County. ... A sequential look at United Flight 175 crashing into the south tower of the World Trade Center The September 11, 2001 attacks (often referred to as 9/11—pronounced nine eleven or nine one one) consisted of a series of coordinated terrorist[1] suicide attacks upon the United States, predominantly...


DVB-S

DVB-S is the original Digital Video Broadcasting forward error coding and modulation standard for satellite television and dates from 1995. It is used via satellites serving every continent of the world, this is even true in North America. DVB-S is used in both MCPC and SCPC modes for broadcast network feeds, as well as for direct broadcast satellite services like Sky Digital (UK & Ireland) via Astra in Europe, Dish Network in the U.S., and Bell ExpressVu in Canada. The transport stream delivered by DVB-S is mandated as MPEG-2. DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 300 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC... Artists impression of a Boeing 601 satellite, as configured for digital television transmission by SES Astra Satellite television is television delivered by way of communications satellites, as compared to conventional terrestrial television and cable television. ... World map showing North America A satellite composite image of North America. ... This article needs more context around or a better explanation of technical details to make it more accessible to general readers and technical readers outside the specialty, without removing technical details. ... Single channel per carrier (SCPC) refers to using a single signal at a given frequency and bandwidth. ... A broadcast network is an organization, such as a corporation or other association, that provides live or recorded content, such as movies, newscasts, sports, and public affairs programs for broadcast over a group of radio or television stations. ... 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. ... Sky Digital is the brand name for British Sky Broadcastings digital satellite television service, transmitted from SES Astra satellites located at 28. ... SES Astra SA, a subsidiary of SES Global, is a Luxembourg-based (in Betzdorf) corporation which owns and operates the Astra series of geostationary satellites, which transmit approximately 1100 analogue and digital television and radio channels via 176 transponders to 91 million households across Europe. ... DISH Network is a direct broadcast satellite (DBS) service that provides satellite television and audio programming to households and businesses in the United States, owned by parent company EchoStar Communications Corporation. ... For other uses, see United States (disambiguation) and US (disambiguation). ... This article contains a trivia section. ... Streaming media are media that are consumed (read, heard, viewed) while it is being delivered. ...


DVB-C

DVB-C stands for Digital Video Broadcasting - Cable and it is the DVB European consortium standard for the broadcast transmission of digital television over cable. This system transmits an MPEG-2 family digital audio/video stream, using a QAM modulation with channel coding. Official DVB logo, found on compliant devices DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 270 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute... 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. DTV uses digital modulation data, which is digitally compressed and requires decoding by a specially designed television set, or a... Coaxial Cable For the weapon, see coaxial weapon. ... MPEG-2 is a standard for the generic coding of moving pictures and associated audio information [1]. It is widely used around the world to specify the format of the digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. ... QAM is a TLA that may stand for: Quadrature amplitude modulation Quality Assurance Management (qam. ... In digital telecommunications, channel coding is a pre-transmission mapping applied to a digital signal or data file, usually designed to make error-correction possible. ...


ISDB

The ISDB system differ mainly in the modulations used, due to the requirements of different frequency bands. The 12 GHz band ISDB-S uses PSK modulation, 2.6 GHz band digital sound broadcasting uses CDM and ISDB-T (in VHF and/or UHF band) uses COFDM with PSK/QAM. It is used mainly in Japan. Integrated Services Digital Broadcasting (ISDB) is the digital television (DTV) and digital audio broadcasting (DAB) format. ...


See also

Transmission technology standards

Defunct analog systems The lists of television channels are grouped by name, country or language: // List of television channels in Africa List of television stations in Central and Western Asia List of television stations in Eastern and Southern Asia List of television stations in Southeast Asia List of television channels in Europe List... The following tables show the frequencies assigned to broadcast television channels in various regions of the world, along with the ITU letter designator for the system used. ... Display standards comparison The display resolution of a digital television or computer display typically refers to the number of distinct pixels in each dimension that can be displayed. ... Amateur television (ATV) is the hobby of transporting broadcast-quality video and audio over radio waves allocated for amateur radio using the broadcast standards of NTSC in North America and Japan, and PAL or SECAM in Europe and elsewhere, using the full refresh rates of those standards. ... North America cable television broadcast band Channels T-7 through T-14 are sub-band channels and are not used for normal television channel distribution. ...

  • 405 lines
  • 819 lines
  • MUSE an Analog high-definition television system still in use in Japan until 2007.

Analog television systems 405 line is the name of a monochrome analogue television broadcasting system in operation in the UK between 1936 and 1985, and also used for some time in Ireland and Hong Kong. ... Historically, the term high-definition television was first used to refer to television standards developed in the 1930s to replace early experimental systems with as few as 12 lines. ... Japan had the earliest working HDTV system, with design efforts going back to 1979. ... Historically the term high-definition television was first used to refer to television standards developed in the 1930s to replace early experimental systems with as few as 12 lines. ...

  • NTSC (525/60) except PAL-M (525/60)
  • NTSC-US a North American NTSC designator (marketing related)
  • PAL-M (television)
  • PAL (625/50) except PAL-M (525/60)
  • PALplus
  • SECAM

Analog television system audio The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... NTSC-US is a videogame territory which covers the North American continent. ... PAL-M is the TV system used in Brazil. ... Television encoding systems by nation. ... PALplus is an extension of the PAL analogue broadcasting system for transmitting 16:9 programs without sacrificing vertical resolution. ... SECAM, also written SÉCAM (Séquentiel couleur à mémoire, French for Sequential Color with Memory), is an analog color television system first used in France. ...

  • NICAM (digital, analog pre-emphasis curve)
  • BTSC
  • Zweiton
  • The defunct MUSE system had a very unusual digital audio subsystem completely unrelated to NICAM.

Digital television systems NICAM (known also as NICAM 728, after the 728 kbit/s bitstream it is sent over), Near Instantaneous Companded Audio Multiplex, is a format for digital sound on analogue television transmissions. ... Multichannel television sound, better known as MTS (often still as BTSC, for the Broadcast Television Systems Committee that created it), is the method of encoding three additional channels of audio into an NTSC-format audio carrier. ... Zweiton (two sounds) is a two-channel television sound transmission system used in Germany and other countries. ... NICAM (known also as NICAM 728, after the 728 kbit/s bitstream it is sent over), Near Instantaneous Companded Audio Multiplex, is a format for digital sound on analogue television transmissions. ...

History High-definition television (HDTV) means broadcast of television signals with a higher resolution than traditional formats (NTSC, SECAM, PAL) allow. ... The Moving Picture Experts Group or MPEG is a working group of ISO/IEC charged with the development of video and audio encoding standards. ... Established in 1982, the Advanced Television Systems Committee (ATSC) is the group that developed the ATSC digital television standard for the United States, also adopted by Canada, Mexico, South Korea, and recently Honduras and is being considered by other countries. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... Advance Television Systems Committe (ATSC) tuner allows reception of over the air high definition digital television signals in North America and South Korea. ... DVB-T stands for Digital Video Broadcasting - Terrestrial and it is the DVB European consortium standard for the broadcast transmission of digital terrestrial television. ... Television encoding systems by nation. ... PALplus is an extension of the PAL analogue broadcasting system for transmitting 16:9 programs without sacrificing vertical resolution. ... SECAM, also written SÉCAM (Séquentiel couleur à mémoire, French for Sequential Color with Memory), is an analog color television system first used in France. ... Integrated Services Digital Broadcasting (ISDB) is the digital television (DTV) and digital audio broadcasting (DAB) format. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ...

// The title of Oldest Television Station is a controversial one, but can be assumed from several in Europe (particularly of England and Germany), and in the United States. ... A number of experimental and broadcast pre World War II systems were tested. ...

References

The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ...

External links


edit Video formats
Analog broadcast
525 lines: NTSC | NTSC-J | PAL-M
625 lines: PAL | PAL-N | PALplus | SECAM
Defunct systems: Pre-1940 | 405 lines | 819 lines | Baird-Nipkow | MAC | MUSE
Multichannel audio: BTSC (MTS) | NICAM-728 | Zweiton (A2, IGR)
Hidden signals: Captioning | Teletext | CGMS-A | GCR | PDC | VBI | VEIL | VITC | WSS | XDS
Digital broadcast
Interlaced: SDTV (480i, 576i) | HDTV (1080i)
Progressive: LDTV (240p, 288p, 1seg) | EDTV (480p, 576p) | HDTV (720p, 1080p)
DVB standards: MPEG-2: ATSC, DVB (S(2)/T/C/IP), ISDB | MPEG-4: SBTVD, DVB (S(2)/T/C/IP)
Multichannel audio: AAC (5.1) | Musicam | PCM | LPCM
Hidden signals: Captioning | Teletext | (CPCM/Broadcast flag) | AFD | EPG
Digital cinema: UHDV (2540p, 4320p) | 22.2 audio
Technical issues: 14:9 | MPEG transport | Standards conversion | Video processing | VOD

  Results from FactBites:
 
Broadcast television system - Gurupedia (1592 words)
An analogue television system includes several components: a set of technical parameters for the broadcast signal, a system for encoding color, and possibly a system for encoding multi-channel audio.
Most video systems were defined to use negative modulation to reduce the appearance of noise, on the theory that dark spots in the image would be less noticeable than bright white spots in the image, given a particularly common sort of noise.
The principal systems are NICAM, which uses a digital audio encoding; double-FM, in which case each audio channel is separately modulated in FM and added to the broadcast signal; and BTSC, which multiplexes additional audio channels on the existing FM audio carrier.
Broadcast television system - Wikipedia, the free encyclopedia (2499 words)
All current analogue television systems are interlaced; that is to say, alternate rows of the frame are transmitted in sequence, followed by the remaining rows in their sequence.
All analogue television systems use vestigial sideband modulation, a form of amplitude modulation in which the lower sideband is incompletely suppressed.
System A was tested with all three colour systems, and production equipment was designed and ready to be built; system A might have survived, as NTSC-A, had the British government not decided to harmonize with the rest of Europe on a 625-line video standard, implemented in Britain as PAL-I on UHF only.
  More results at FactBites »

 
 

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