{{Refimprove|date=July 2007}}
'''Analog''' (or '''analogue''') '''television''' encodes [[television]] picture and sound information and transmits it as an [[analog signal]], that is say: one in which the message conveyed by the broadcast [[Signal (information theory)|signal]] is a function of deliberate variations in the amplitude and/or [[frequency]] of the signal. All systems preceding [[digital television]], such as [[NTSC]], [[PAL]] or [[SECAM]] are analog television systems.

Broadcasters using analog television systems encode their signal using [[NTSC]], [[PAL]] or [[SECAM]] analog encoding and then modulate this signal onto a [[Very high frequency|VHF]] or [[Ultra high frequency|UHF]] carrier. An analog television picture is "drawn" on the screen an entire frame each time, in the manner of a motion picture (cinematograph) film, irrespective of the picture content.

==Analog television technology==
Analog television, like all other motion picture systems, exploits the properties of the human eye to create the illusion of moving images. The human eye retains an image for a fraction of a second, which is called "persistence of vision". Due to the persistence of vision effect, a rapid sequence of images will be perceived as an integrated moving image. If the rate of frames is too low, such as 16 frames per second, the moving images will seem jumpy and jerky. Frame rates of 24 frames per second were used for motion pictures to create a smooth moving image. When [[NTSC]] television standards were developed, 30 Hz was chosen at the frame rate, and then later 29.97 Hz. The [[PAL]] system has a frame rate of 25 frames per second.

When onscreen images are bright, the persistence of vision effect does not last as long, which meant that more frames had to be projected per second. Motion picture projectors resolve this problem by using shutters. Since shutters cannot be used for televisions, television engineers increased the repetition rate to two "flashes" per frame by interlacing and scanning a single frame two times. These interlacing repeated frames do come at a cost, though; in some cases, the repeated frames cause aberrations such as serrations on the edge of moving objects, misalignment, interline flicker, or a shimmering effect.

In black and white television based on a cathode ray tube (CRT), a single electron beam scans a phosphor screen from left to right and then returns to the top. The electron beam is brightness-modulated to create intensity changes which cause the different shades of grey. Analogue television equipment has been manufactured using alternative forms of display, such as LCD, but the picture display is still updated a frame at a time in the same manner as the flying-spot CRT.

To support color signals contained in the broadcast, a color synchronization signal called a "color burst" is added to the basic black and white information. When color television was introduced, engineers ensured that black and white televisions would still be able to display signals that were broadcast in color. To do this, the original monochrome information is still transmitted in the color signal, and then the color difference information is added on top.

Three major standards for television are American [[NTSC]] (National Television Systems Committee) color television system, the European [[PAL]] (Phase Alternation Line rate) and the French-Former Soviet Union [[SECAM]] (Sequential Couleur avec Memoire) standard. The three systems have different numbers of vertical lines. NTSC uses 525 lines (interlaced). In contrast, PAL and SECAM use 625 lines. NTSC displays more frames per second than PAL and SECAM. PAL's color encoding is similar to the NTSC system's. SECAM, though, uses a different modulation approach than PAL or NTSC.

==Digital switchover==
Many countries have, or have decided to, cease analog transmissions to switch to digital broadcasting.
===Switch-off completed===
[[Image:Finnishanalog.jpg|thumb|200px|Notice on Finnish analog TV, telling people about the shutdown.]]
* [[Luxembourg]] was the first country to complete the move to digital broadcasting on [[1 September]] [[2006]].

* [[The Netherlands]] moved to digital broadcasting on [[11 December]] 2006. The switch-off was helped greatly by the fact that about 90% of the households have cable that continues to use analog distribution.

* [[Finland]] completed its switch-off on [[1 September]] [[2007]].

* [[Andorra]] completed its switch-off on [[25 September]] 2007.

* In [[Sweden]], the switch-off of the analog terrestrial network progressed region–by–region. It started on the island of Gotland on [[15 September]] [[2005]], and was completed on [[29 October]] 2007, when the last analogue SVT1 transmitters in Scania and Blekinge were shut down. Cable distributors are allowed to continue broadcasting analogue television.

* [[Switzerland]] began with the switch-off on [[24 July]] 2006 ([[Tessin]]) and continued with [[Engadin]] on [[13 November]] 2006. The switch-off was completed on [[26 November]] 2007.


===Switch-off in progress===

* [[Germany]] started the switch-off at different times in different regions. The first was the Berlin area, where the switch-off began on [[1 November]] [[2002]] and was completed on [[4 August]] [[2003]]. Most other regions have followed, and in most populous areas the switch-off is completed, but a number of regions have not yet started. The switch-off is planned to be completed by the end of 2008.

* In the [[United Kingdom]], the switch-off of all analogue terrestrial TV broadcasts began on the [[17 October]] [[2007]] with [[Whitehaven]] in [[Cumbria]]<ref>{{web cite|url=http://news.bbc.co.uk/1/hi/entertainment/6453087.stm|title=First digital TV switch date set|publisher=[[BBC News]]|accessdate=2007-04-24|date=2007-03-15}}</ref> and will proceed region by region. The last regions will be switched off in [[2012]]. There is a free-to-air Digital Terrestrial replacement called [[Freeview]] that complies with the DVB-T standard. A set-top box can be bought to enable analogue television sets to receive [[Freeview]]. Experts are already predicting what will become of the UK frequencies, including truly wireless broadband, high-definition [[Freeview]] services and interactive services.<ref>{{web cite|url=http://www.computing.co.uk/vnunet/news/2146345/going-happen-uhf-analogue-tv|title=Ofcom ponders future of analogue TV spectrum|publisher=Computing|accessdate=2007-11-02|date=2007-11-21}}</ref>

* [[Austria]] began analog switch-off on [[5 March]] [[2007]], progressing from the west to the east.

* In [[Norway]], the switch-off started in late 2007 and will finish by 2009.

===Switch-off time announced===
* In [[Australia]], the government originally planned a switch-off in 2008. This has now been delayed to a "to be determined" date in 2010-2012. Until that time, free-to-air stations will be simulcast, along with digital only channels like [[ABC2]]. Legislation has required all locally made free-to-air television transmissions to be in 16:9 [[Widescreen]] format since 1999 (a world first). Cable television networks began simulcasting in 2004 and analog cable services were switched off in April 2007.

* [[Belgium]] will switch to digital broadcasting completely by November 2008. It will happen gradually, starting in January.

* In [[Brazil]], free-to-air digital broadcasting will officially start on December 2, 2007 in [[São Paulo]], then in January 2008, [[Brasília]], [[Rio de Janeiro]], and [[Belo Horizonte]]. Digital broadcasts will be phased into the other 23 state capitals by the end of 2009. Remaining cities have until December 31, 2013. Broadcasting companies must simulcast in both analog and digital channels until June 29, 2016, when all analog TV broadcasts will cease.

* In [[Canada]], the main FTA broadcasters ([[Canadian Broadcasting Corporation|CBC]], [[CTV television network|CTV]], and [[Global Television Network|Global]]) have launched HD streams of their programming. Currently, analog and digital broadcasts co-exist, with virtually the only way to receive digital TV via cable or satellite TV. However, in some urban areas like [[Toronto]], it's also possible to pick up [[Digital terrestrial television|DTV]]. Canadian broadcasters must switch to digital over-the air signals by [[31 August]] [[2011]], although exceptions may be made where analog transmissions will not cause interference (e.g. remote areas). <ref>{{cite web |url= http://www.crtc.gc.ca/archive/ENG/Notices/2007/pb2007-53.htm |title= Broadcasting Public Notice CRTC 2007-53: Determinations regarding certain aspects of the regulatory framework for over-the-air television | accessdate= 2007-07-16 |date= [[2007]]-[[05-17]] |publisher= [[Canadian Radio-television and Telecommunications Commission]] }}</ref>

* In [[China]], the switch-off is scheduled to be in 2015.

* In [[Denmark]], digital transmission has started and the analog net will be closed at the end of October 2009.

* In [[Republic of Ireland|Ireland]] DVB-T trials are being held but the digital switch-over, which was intended to begin in 2008 has been postponed indefinitely.

* In [[Japan]], analog transmissions will be terminated nationwide in July 2011.

* In [[Malaysia]], Information Ministry was planning to shut down the country's analog television system in phases beginning from 2009 and set to convert to full digital TV in 2015.

* In [[New Zealand]], It was announced on the 29 November 2007 That the analogue TV broadcasts will end within the next 6 to 10 years and expect a switch off date to be announced by 2012. Digital broadcast via Free View become available late 2007.

* In [[Slovenia]], analog transmissions will be terminated on [[31 December]] [[2010]].

* In [[Spain]], the switch-off will be completed on [[3 April]] [[2010]].

* In [[Ukraine]], analog transmissions will be terminated on [[17 July]] [[2015]].[http://comments.com.ua/?spec=1173973950&sart=1173974411]

* In the [[United States]] by no later than [[February 17]], [[2009]], all U.S. television broadcasts will be exclusively digital, by order of the [[Federal Communications Commission]], with legislation setting this deadline signed into law in early 2006.<ref>Section 3002 of the [[Deficit Reduction Act of 2005]], Pub. L. No. 109-171, 120 Stat. 4 (February 8, 2006), amending the [[Communications Act of 1934]], section 309(j)(14), codified at {{usc|47|309(j)(14)}}.</ref> Furthermore, starting [[March 1]], [[2007]], new television sets that receive signals over-the-air, including pocket sized portable televisions, must include digital tuners (for HD or SD broadcasts, or both).<ref>{{web cite|url=http://www.boston.com/business/technology/articles/2007/02/26/fcc_rule_requires_all_new_tvs_to_be_digital/|title=FCC rule requires all new TVs to be digital|publisher=[[The Boston Globe]]|accessdate=2007-04-24|date=2007-02-26}}</ref> Currently, most U.S. broadcasters are beaming their signals in both analog and digital formats; a few are digital-only. Citing the bandwidth efficiency of digital TV, after the analog switch-off the FCC will auction off channels 52–59 (the lower half of the 700&nbsp;MHz band) for other communications traffic<ref>{{cite web |url= http://wireless.fcc.gov/services/index.htm?job=service_home&id=lower700 |title= FCC: Wireless Services: Lower 700 MHz |accessdate= 2007-05-09 |date= [[2004]]-[[10-28]] |publisher= [[Federal Communications Commission]] }}</ref>, completing the reallocation of broadcast channels 52–69 that began in the late 1990s. The analog switch-off ruling, which so far has met little opposition from consumers or manufacturers, would render all non-digital televisions obsolete within 2 years. The FCC has determined that an external tuning device can simply be added to non-digital televisions to lengthen their useful lifespan. (However, as of March 2007, external tuning devices are not widely available, are relatively expensive, and require bulky AC power supplies.) Currently, even the earliest televisions continue to work with present broadcast standards. This mandate was designed to help provide a painless transition to the new standards. On [[September 12]], [[2007]], the FCC voted 5-0 on requiring cable operators to make local broadcasts available to their users, even those with analog television. This requirement lasts until 2012, when the FCC will review the case again.

==Common analog television systems==
* [[NTSC]]
* [[PAL]]
* [[SECAM]]
* [[Slow-scan television]]
* [[Narrow-bandwidth television]]

{{Wireless video}}
==See also==
* [[Broadcast television system]]
* [[Terrestrial television]]
* [[Analog transmission]]

==References==
{{reflist|1}}

[[Category:Film and video technology]]
[[Category:History of television]]

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