View source for PALplus

{{Short description|Analogue widescreen television broadcasting system}}
{{Multiple issues|
{{More citations needed|date=May 2023}}
{{Original research|date=May 2023}}
}}
[[File:PALplus pattern of the Philips PM5420.png|thumb|PALplus pattern of the [[Philips circle pattern|Philips PM5420]] test pattern generator]]

'''PALplus'''<ref name="auto">{{cite web |title=Recommendation ITU-R BT.1197-1 Enhanced wide-screen PAL TV transmission system (the PALplus system) |url=https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.1197-1-199802-W!!PDF-E.pdf |website=itu.int}}</ref> (or ''PAL+'') is an analogue television broadcasting system aimed to improve and enhance the [[PAL]] format by allowing [[16:9]] (or 1.77:1) [[aspect ratio]] broadcasts, while remaining compatible with existing television receivers,<ref name="auto2">{{cite web |url=https://assets.fluke.com/appnotes/it_products/B0291A-16U9509_NL_EN.pdf |title=Fluke PM5420 Application Note PALplus |website=assets.fluke.com |access-date=12 January 2022 |archive-url=https://web.archive.org/web/20160303224309/https://assets.fluke.com/appnotes/it_products/B0291A-16U9509_NL_EN.pdf |archive-date=3 March 2016 |url-status=dead}}</ref> defined by [[International Telecommunication Union]] (ITU) recommendation BT.1197-1.<ref name="auto"/> Introduced in 1993,<ref name="auto1">{{cite web |url=https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31993D0424:EN:HTML |title=EUR-Lex - 31993D0424 - EN |website=Official Journal L 196 |date=5 August 199 |pages=48–54}}</ref> it followed experiences with the [[HD-MAC]] (high definition) and [[D2-MAC]], hybrid analogue-digital widescreen formats that were incompatible with PAL receivers. It was developed at the [[Technical University of Dortmund|University of Dortmund]] in [[Germany]], in cooperation with German terrestrial broadcasters and European and Japanese manufacturers. The system had some adoption across Europe during the late 1990s and helped introduce widescreen TVs in the market, but never became mainstream.{{Citation needed|date=May 2024}} 

A similar system, developed in Japan at the same time and named [[Clear-Vision|EDTV-II/ Wide-aspect Clear-vision]], allows for 16:9 NTSC broadcasts.'''<ref>{{cite journal |last1=Nakayama |first1=K. |last2=Kojima |first2=T. |last3=Miyaguchi |first3=H. |last4=Sawaragi |first4=T. |last5=Yaguchi |first5=Y. |date=August 5, 1995 |title=EDTV-II decoder by SVP2 (the 2nd generation of scan-line video processor) |url=https://ieeexplore.ieee.org/document/468089 |journal=IEEE Transactions on Consumer Electronics |volume=41 |issue=3 |pages=634–642 |doi=10.1109/30.468089 |via=IEEE Xplore |url-access=subscription}}</ref><ref>{{cite web |title=The Journal of the Institute of Television Engineers of Japan |url=https://www.jstage.jst.go.jp/browse/itej1978/49/9/_contents/-char/en |website=www.jstage.jst.go.jp}}</ref><ref name=":8">{{cite web |last=FUKINUKI |first=Takahiko |title=EDTV |date=March 1991 |url=https://search.ieice.org/bin/summary.php?id=e74-b_3_540}}</ref><ref name=":13">{{cite news |last=Pollack |first=Andrew |date=September 15, 1994 |title=Japanese Taking to Wide-Screen TV |work=The New York Times |url=https://www.nytimes.com/1994/09/15/business/japanese-taking-to-wide-screen-tv.html |via=NYTimes.com}}</ref><ref>{{cite web |title=EDTV2 試験放送 画質評価用スライド放送 |url=https://www.youtube.com/watch?v=K7hFBvAHFq8 |via=www.youtube.com}}</ref>'''

== History ==
The [[Multiplexed Analogue Components|MAC]] family of standards was adopted in Europe in 1983,<ref name="auto12">{{cite web |last=Government of Canada |first=Public Works and Government Services Canada |date=8 October 2009 |title=D2-MAC [1 record] - TERMIUM Plus® — Search - TERMIUM Plus® |url=https://www.btb.termiumplus.gc.ca/tpv2alpha/alpha-eng.html?lang=eng&i=1&index=ent&codom2nd_wet=1&srchtxt=D2-MAC |website=www.btb.termiumplus.gc.ca}}</ref> primarily for [[Satellite television#Direct-to-home and direct broadcast satellite|Direct Broadcasting by Satellite (DBS)]] services. This was an evolution from older color TV systems (such as PAL or [[SECAM]]) fixing the problems of interference between [[luminance]] and [[chrominance]], and providing a stepping stone for a future HDTV system. <ref>{{cite book |last=ITU Radiocommunication Assembly |url=https://extranet.itu.int/brdocsearch/R-REC/R-REC-BO/R-REC-BO.650/R-REC-BO.650-2-199203-I/R-REC-BO.650-2-199203-I!!PDF-E.pdf#page=18 |title=Recommendation ITU-R BO.650-2 - Standards for conventional television systems for satellite broadcasting in the channels defined by Appendix 30 of the Radio Regulations |year=1992 |pages=18}}</ref><ref name="auto12"/>  In 1986, a new [[High-definition television|high definition]] broadcasting standard, HD-MAC, was presented, offering twice the number of scanning lines compared to PAL.<ref name="auto5">{{cite book |last=Pauchon |url=https://tech.ebu.ch/docs/techreview/trev_253-analogue.pdf |title=EBU Technical Review |publisher=EBU |year=1992 |edition=Autumn |pages=6–19 |chapter=Analogue HDTV in Europe}}</ref> A transitional standard, D2-MAC was established.<ref>{{cite web |date=8 October 2009 |title=D2-MAC &#91;1 record&#93; - TERMIUM Plus® — Search - TERMIUM Plus® |url=https://www.btb.termiumplus.gc.ca/tpv2alpha/alpha-eng.html?lang=eng&i=1&index=ent&codom2nd_wet=1&srchtxt=D2-MAC}}</ref> It had the same number of lines as PAL, but like HD-MAC it was designed for 16:9 widescreen content. 

In 1989, the PALplus strategy group was founded. The goal was to develop an enhanced system for terrestrial transmission compatible with PAL. European terrestrial broadcasters felt the need to better position themselves in order to compete with satellite and cable operators, in view of the introduction of MAC widescreen broadcasts. While not attempting to produce HDTV standards of quality, the new format was meant to improve PAL in the following areas:
* Wider aspect ratio, but with acceptable effects on the traditional [[Fullscreen (aspect ratio)|4:3]] (or 1.33:1) screen
* Reduced level of artefacts, such as [[Composite video#Composite artifacts|cross-color]]
* Better sound system
* Improved [[Display resolution|resolution]]
* Compatibility with existing receivers.<ref>{{cite book |url=https://books.google.com/books?id=NWUQBwAAQBAJ&q=palplus+high+definition&pg=PA9|title=Coding and Modulation for Digital Television |author=Gordon M. Drury, Garik Markarian, Keith Pickavance |date=11 April 2006 |publisher=Springer |isbn=9780306470363}}</ref>

In the beginning, the task group consisted of the public broadcasting corporations of Germany ([[ARD (broadcaster)|ARD]] and [[ZDF]]), Austria ([[ORF (broadcaster)|ORF]]), Switzerland ([[Swiss Broadcasting Corporation|SRG]]) and the United Kingdom ([[BBC]] and [[United Kingdom Independent Broadcasting|UKIB]], United Kingdom Independent Broadcasters) together with the consumer electronics manufacturers [[Grundig]], [[Nokia]], [[Philips]] and [[Vantiva|Thomson]].<ref>{{Cite web|url=https://tech.ebu.ch/docs/techreview/trev_253-analogue.pdf|title=EBU Technical Review - Analogue HDTV in Europe, Autumn 1992}}</ref> [[Sony]] as well as the Spanish ([[RTVE]]) and Portuguese ([[Rádio e Televisão de Portugal|RTP]]) broadcasters joined the group later on.

At the Berlin [[IFA Berlin|IFA]] 1991, a first PALplus test transmission was demonstrated<ref>{{cite web |url=https://patents.google.com/patent/EP0654950A2/en |title=Method for measuring, adjusting and/or equalizing transmission channels and/or television signal decoders}}</ref><ref>{{cite web |url=https://www.thefreelibrary.com/HDTV+on+world+stage.-a011514191 |title=HDTV on world stage. - Free Online Library |website=www.thefreelibrary.com}}</ref>

At the Berlin IFA 1993, the first experimental PALplus broadcasts began.<ref>{{cite book |chapter-url=https://ieeexplore.ieee.org/document/738124|title=The PALpus project: conception to introduction |first=R.J.G. |last=Ellis |chapter=The PALplus project: Conception to introduction |date=September 19, 1994 |volume=1994 |pages=8–19 |via=IEEE Xplore |doi=10.1049/cp:19940720|doi-broken-date=7 December 2024 }}</ref> In the same year, the [[European Union]] approved a plan to support the production and broadcast of 16:9 programs.<ref name="auto1"/><ref>{{cite book |url=http://aei.pitt.edu/3115/1/3115.pdf |title=Second annual report on progress in Implementing the action plan for the introduction of advanced television services in Europe |publisher=Commission of the European Communities |year=1996}}</ref>

In 1994, broadcasters began adopting the format. In the United Kingdom, [[Channel 4]] starts to broadcast using the system in October.<ref name=":0">{{cite web |url=https://www.newscientist.com/article/mg14319383-400-technology-wide-screens-split-bbc-and-channel-4ry-fox/ |title=Technology: Wide screens split BBC and Channel 4ry Fox |website=New Scientist}}</ref><ref name=":1">{{cite web |url=https://the-media-leader.com/c4-emits-widescreen-formats/ |title=C4 Emits Widescreen Formats - The Media Leader |date=August 3, 1994}}</ref> Nokia launched the first PALplus TV set in Germany.

In 1995, the International Telecommunication Union publishes recommendation BT.1197-1, defining the PALplus system.<ref name="auto"/> Originally, the PALplus consortium included the following manufacturers: Philips, Grundig, Thomson, Nokia and Sony. One of the four big Korean electronics manufacturers, [[Samsung]], joined the PALplus consortium that year.<ref name="rec-bt1197">{{cite web |title=Recommendation ITU-R BT.1197-1: Enhanced wide-screen PAL TV transmission system (the PALplus system) |url=https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.1197-1-199802-W!!MSW-E.doc}}</ref> [[Videocassette recorder|VCR]] manufacturers associated with the PALplus consortium were expected to launch updated [[VHS]] and [[S-VHS]] home recorders soon. The cost increment compared to conventional PAL VCRs was expected to be small.<ref name="rec-bt1197"/> PALplus was one of the highlights of the Berlin IFA 1995 edition.<ref>{{cite web |url=https://berlin.barwick.de/freetime-leisure/events/ifa-internationale-funkausstellung.html#highlights |title=» IFA - Internationale Funkausstellung - Berlin Guide in English |website=berlin.barwick.de}}</ref>

In January 1996, the PALplus board published the specifications of the standard in order to support the further dissemination of this standard for wide-screen transmissions. After German broadcasters started to broadcast some of their programmes using the format, the board ended its work by the end of that same year.{{Original research inline|date=May 2023}}

At the beginning of 1998, PALplus programmes were broadcast on a regular basis in nine European countries, which made PALplus the mostly used standard for widescreen transmissions in Europe at that time. Evaluations, performed by [[International Telecommunication Union|ITU]] and [[European Broadcasting Union|EBU]] engineers in 1995-1998 concluded that the use of down-converted HDTV source material, as well as high-quality widescreen standard definition content, could be a significant benefit to the PALplus picture quality. Moreover, the experts felt that PALplus would not be out of place in an HDTV environment at viewing distances equal or farther to four heights of a television set. It was presumed that the standard method of display of a PALplus signal would be in 625-line interlaced (50&nbsp;Hz) form, although other display formats (for example, 50&nbsp;Hz [[Progressive scan|progressive]], 100&nbsp;Hz interlace, or 100&nbsp;Hz progressive) could be receiver options.{{Citation needed|date=May 2023}}

== Countries and territories that used PALplus ==<!-- This is information that is truly a list in nature.  Converting it to prose would obfuscate it and make it harder to read, use, edit and update.  Please do not tag this genuine list for conversion to "prose" -->

The following countries and territories used the PALplus system:
* {{flag|Austria}}
* {{flag|Belgium}}
* {{flag|Finland}}
* {{flag|Germany}}
* {{flag|Greece}}
* {{flag|Ireland}}
* {{flag|Italy}}
* {{flag|Netherlands}}
* {{flag|Poland}}
* {{flag|Portugal}}
* {{flag|Spain}}
* {{flag|UK}}

=== Belgium ===
In [[Belgium]], the Flemish public broadcasting service [[Vlaamse Radio- en Televisieomroep|VRT]] had a policy that all of its self-created TV programmes are broadcast in PALplus.<ref name="auto4">{{cite web |url=https://www.radio-tv-nederland.nl/rbrdx/BRT1%20pal%20plus.jpg |title=BRT PALplus test card image |website=radio-tv-nederland.nl}}</ref> The commercial TV station [[VTM (TV channel)|VTM]] used to broadcast a lot in PALplus. Even the third broadcasting organisation [[ProSiebenSat.1 Media|SBS Belgium]] with its stations [[VT-4|VT4]] and [[Play5|VijfTV]] used to broadcast in PALplus for all of their new productions.

The Walloon public broadcasting service [[RTBF]] used to broadcast 16:9 programmes that it purchased in PALplus, but preferred creating their own programmes in 4:3. Walloon commercial TV station [[RTL-TVI]] used to broadcast almost all its shows in PALPlus.<ref>{{cite web |url=https://www.youtube.com/watch?v=TNYEoTJ1r8A |title=RTL-TVI Fermeture Antenne Mai 1997 + Mire PALPlus |via=www.youtube.com}}</ref>

In 2010, Belgium switched off analog television broadcast.<ref>{{cite web |url=https://www.broadbandtvnews.com/2010/02/08/belgium-completes-analogue-switchover/ |title=Belgium completes analogue switchover |date=February 8, 2010 |website=Broadband TV News}}</ref>

=== Finland ===
In [[Finland]], the commercial broadcaster [[MTV3]] started broadcasting the youth music program ''Jyrki'' in PALplus format on August 18, 1997.<ref>{{cite web |title=HIM Live @ MTV3 Jyrki Ville Valo Birthday 1999 |url=https://www.youtube.com/watch?v=_R5WPspX3mc |via=www.youtube.com}}</ref><ref>{{cite web |title=Plan E live interview @ MTV3 Jyrki (1999) |url=https://www.youtube.com/watch?v=16fLiV0nbxM |via=www.youtube.com}}</ref> The experiment ended when the program ended some four years later.

In 2007, Finland switched off analog television broadcast.<ref name="50countriesoff" />

=== Germany ===
In Germany, all public broadcasters ([[Das Erste|ARD]],<ref>{{cite web |url=https://www.flickr.com/photos/tim_anderson/51589149554/ |title=Astra ARD PAL Plus |date=October 8, 2021 |via=Flickr}}</ref><ref>{{cite web |url=https://www.youtube.com/watch?v=biodT3rxFK4 |title=Test Card Telefunken FuBK PALplus |via=www.youtube.com}}</ref> ZDF, ''etc.'') complied with this standard. However, private broadcasters ([[RTL Television|RTL]], [[ProSieben]], ''etc'') have shown no interest in either this standard or in the 16:9 format.{{Dubious|date=March 2010}}{{Citation needed|date=March 2010}}

Pay-per-view channels such as those on [[Sky Deutschland|Sky]] often broadcast in 16:9, but use a different standard that requires another kind of decoder.

In 2008, Germany began switching off analog television broadcast.<ref name="50countriesoff">{{cite web |url=https://www.atsc.org/news/nearly-50-countries-switch-off-analog-tv/ |title=Nearly 50 Countries Switch Off Analog TV |date=July 7, 2015 |website=ATSC: NextGen TV}}</ref>

=== Greece ===
In [[Greece]], there were sporadic PALplus broadcasts on the national television ([[Hellenic Broadcasting Corporation|E.R.T.]] - Hellenic Radio Television). Throughout the '90s several attempts from commercial broadcasters in adopting the system failed due to lack of popularity.

As some of the repeaters of ERT's channels were fed via [[OTE]] (Greek public telecom provider) in uncompressed form over terrestrial links, and others via [[Nova (Greece)|NOVA]] (Greece's only satellite platform) using [[Moving Picture Experts Group|MPEG]] encoding, Palplus wasn't available on all areas. The heavy MPEG [[Code|encoding]] on NOVA [[Degradation (telecommunications)|degraded]] WSS signaling and the additional information embedded in PALplus, making it undecodable.

=== Italy ===
It was used by broadcasters such as [[RAI]] (Italy).<ref>{{cite web |title=Television Graphics Around the World |url=http://www.meldrum.co.uk/mhp/testcard/around_world.html |website=www.meldrum.co.uk}}</ref>

=== Ireland ===
[[RTÉ]] Ireland’s public service broadcaster, began to broadcast widescreen programming in 1995, initially on [[RTE2|Network 2]] Television in a special slot, mostly focused on documentaries, music and feature films, but over time more widescreen programming was introduced.<ref>{{cite web |title=RTÉ announces the introduction of widescreen television broadcasting throughout the country on an experimental basis. |url=https://www.rte.ie/archives/2012/1022/342615-widescreen-broadcasting-explained-1995 |website=RTÉ Archives}}</ref>

=== Netherlands ===
In the [[Netherlands]], the public broadcasters used PALplus up to 2005.<ref>{{Cite web|url=https://www.youtube.com/watch?v=4fSH11pCqVA|title=Pal plus info 1998|via=www.youtube.com}}</ref><ref>{{cite web|url=https://www.youtube.com/watch?v=oYGxuIPByRU |title=Testbeeld NOZEMA Ned 3 PALplus met radio 18-9-1998 |via=www.youtube.com}}</ref> With the switch to [[DVB|digital television]] and anamorphic widescreen, the system was discontinued with the end of terrestrial analogue broadcasts in November 2006. Analog broadcasts continued on cable operations, but PALplus wasn't used for down conversion on those services.

=== Poland ===
In [[Poland]], the only documented use of PALplus is by [[TVP Polonia|TV Polonia]] on December 31, 1996.<ref>{{cite web |archive-url=https://web.archive.org/web/20151004151919/http://www.archiwum.wyborcza.pl/Archiwum/1,0,234581,19961223RP-DGW,PalPlus_na_sylwestra,.html |title=PalPlus na sylwestra - Gazeta Wyborcza |url=http://www.archiwum.wyborcza.pl/Archiwum/1%2C0%2C234581%2C19961223RP-DGW%2CPalPlus_na_sylwestra%2C.html |archive-date=2015-10-04 |via=archiwum.wyborcza.pl}}</ref><ref>{{cite web |url=https://www.youtube.com/watch?app=desktop&v=h9iOETx7ro8 |title=Premiera PALplus [16:9] w TVP - 31.12.1996 r. |via=www.youtube.com}}</ref>

=== Portugal ===
In [[Portugal]], the private broadcaster [[Televisão Independente|TVI]] began broadcasting movies in PALplus in 1994,<ref>{{cite web |url=https://www.youtube.com/watch?v=iZOTBdljq30 |title=4 TVI a Emitir em PAL PLUS 1994 Sozinho em Casa|via=www.youtube.com}}</ref> but some years after it left the standard behind.

The public broadcaster RTP started using the format on December 5, 1997.<ref>{{cite web |url=http://www.cinedie.com/169.htm |title=16:9 |website=www.cinedie.com}}</ref>

The system was used to broadcast selected programs (about five programs each day) and some widescreen movies on analog terrestrial broadcasts. Cable distributors occasionally strip the signal of the [[Widescreen signaling|WSS bits]], rendering the system inoperative. Also, when [[Digital terrestrial television|Digital Terrestrial Television]] broadcasts started, there was no dedicated [[Anamorphic format|anamorphic]] [[simulcast]] for the digital channels. Therefore, PALPlus over terrestrial analog PAL broadcasts remained the only source of 576 lines widescreen TV in Portugal for many years.

Since the middle of 2010 PALplus was dropped in favor of regular [[Letterboxing (filming)|16:9 letterbox]], because the system caused considerable image degradation (with an effective horizontal resolution of only about ~400px compared to 720px of a digital [[Standard-definition television|SDTV]] image) when used on digital transmissions without any decoding.

With the end of analog broadcasts by 2012, the system became officially obsolete.

=== Spain ===
In [[Spain]], the system was used by the public broadcaster RTVE.<ref name="auto3">{{cite web |url=http://ing-sat.what.hu/testcard-sat/spain.htm |title=Spain |website=ing-sat.what.hu}}</ref> The Catalan public television, [[TV3 (Catalonia)|TV3]], trialed the PALplus format in 1994, with a weekly broadcast of a film in this format.<ref>{{cite web |url=https://1library.co/article/los-servicios-interactivos-en-la-televisi%C3%B3-de-catalunya.zkx53w4y |title=Los servicios interactivos en la Televisió de Catalunya |website=1library.co}}</ref> Other public regional stations (like Galicia's [[Corporación Radio e Televisión de Galicia|CRTVG]]) tested the format too, but after these trials the technology was dropped and 16:9 digital broadcasts were not introduced until 2007.

=== United Kingdom ===
In the United Kingdom, Channel 4 adopted the system to broadcast selected films after October 1994.<ref name=":0" /><ref name=":1" /> Some programmes, including ''[[Fifteen to One]]'' and the omnibus edition of ''[[Brookside (TV series)|Brookside]]'' were also broadcast this way. BBC didn't adopt the system, opting instead for digital widescreen broadcasts.<ref name=":0" /> All of the six main broadcasters, BBC, [[ITV (TV network)|ITV]], Channel 4, [[Channel 5 (British TV channel)|Five]], [[Sky UK|Sky]] and [[Virgin Media]], now broadcast in digital.

Analog television broadcast was switched off in the United Kingdom in 2012.<ref>{{cite news|url=https://www.bbc.com/news/av/technology-20054117|title=UK completes TV switchover|work=BBC News}}</ref>

== Operation ==
A standard PAL receiver will display the 16:9 image in letterbox format with 432 active lines. This reproduces noticeably less detail than the 576 lines used for 4:3 broadcasts. A '''PALplus''' receiver can use extra information hidden in the black bars above and below the image to fully recover the 576 lines of vertical resolution.<ref name="auto2"/>

For compatibility reasons, the horizontal bandwidth remains at 5.0&nbsp;[[Hertz|MHz]]. This means that a PALplus signal provides no extra horizontal resolution to compensate for the image being stretched across a wider screen. The result is a horizontal resolution that is 73% of the vertical resolution, or 51% when the [[Kell factor]] is ignored.

A special signal tells the receiver when PALplus is in use, and also whether the original content was [[Interlaced video|interlace]]d ("Camera mode" or 50i) or [[progressive scan]]ned ("Film mode" or 25p) - see [[List of broadcast video formats]]. An additional signal can enable a "[[Ghosting (television)|Ghost]] Cancellation" feature.

A separate feature related to PALplus is '''ColourPlus''', which improves colour decoding performance.<ref name="auto2"/>

=== Extensions ===
The PALplus standard comprises three extensions to standard PAL:<ref name=autogenerated2>{{cite web |archive-url=https://web.archive.org/web/20160303233323/http://stoneship.org.uk/~steve/palplus.html |archive-date=3 March 2016 |title=All You Ever Wanted to Know About PALplus but were Afraid to Ask |url=http://stoneship.org.uk/~steve/palplus.html}}</ref>

==== Vertical helper ====
A broadcaster creates a PALplus signal by scaling an [[Anamorphic widescreen|anamorphic]] 16:9 picture with 576 lines down to 432 lines, so that the picture appears [[Letterboxing (filming)|letterboxed]] on a regular PAL TV set. For [[Luma (video)|luminance]], the scaling is done using a pair of matching [[Low-pass filter|low-pass]] and [[High-pass filter|high-pass filters]], with the low-pass result being the regular PAL compatible letterbox broadcast. One out of every 4 lines of the high-pass result is hidden in the remaining 144 black letterbox lines at the top and bottom of the picture, using the [[YUV|U]] [[Subcarrier|colour subcarrier]]. The filtering is such that this is enough to restore the complete 576 line resolution. The use of the colour subcarrier means these signals appear as very dark blue and yellow patterns on black bars on a regular 4:3 PAL TV set.

The 16:9 PAL-plus receiver combines 432 normally visible lines plus 144 helper lines, restoring the original 576 lines. In "Film mode" (progressive scan), this operation is performed on a per-[[Film frame|frame]] basis, while in "Camera mode" ([[Interlaced video|interlaced]]) the operation is performed per-[[Field (video)|field]].

==== Colour-plus (or Clean PAL) ====
The PAL colour carrier is modulated making use of [[correlation]] between 2 fields, in order to give a cleaner luminance/[[chrominance]] separation in the PALplus receiver. It is used with signals with high horizontal luminance frequencies (3&nbsp;MHz) that share the spectrum with the chrominance signals. Colour pictures on both standard and PALplus receivers are enhanced.

For progressive "Film mode" material, "Fixed" Colour-Plus is used, as there is no motion between the image fields.
For camera based images, "Motion Adaptive Color-Plus" (MACP) is used based on movement.

==== Signaling bits ====
A special [[Widescreen signaling|WSS signal]] tells the receiver whether 4:3/16:9/PALplus is in use, and also whether the original content was interlaced ("Camera mode") or progressive scanned ("Film mode"). An additional signal can enable a "[[ghosting (television)|Ghost]] Cancellation" feature. The bandwidth of these bits is low enough to be recorded on VHS and allow the receiver to switch to the proper format.

== PALplus compatible sets ==
<!-- Deleted image removed: [[File:Philips 28PW9763 CRT television user manual.jpg|right|300px|thumb|Philips 28PW9763 CRT TV set (1998 brochure)]] -->

The standard permits using the mark "PALplus" if the vertical helper reconstruction is implemented, with Colour-plus being optional.

Some PALPlus compatible sets:<ref name=autogenerated2 />
* Grundig: MFW82-710/9, MFW82-720/9, MFW82-730/9 DVD, M82-169/9
* Nokia: Nokia 8297, Nokia 7297, Nokia 6197
* Philips: 28PW9525, 32PW9525, 36PW9525
* [[Schneider Rundfunkwerke|Schneider]]: Scinema 28-100T, Scinema 2810, Scinema 3000
* Sony: KV-W 3213D, KV-32W3(S)

PALplus set top decoders:<ref>{{cite web |url=http://www.pix.net/mirrored/discordia.org.uk/~steve/palplus.html#hotlinks |title=PALplus |website=www.pix.net}}</ref>
* Nokia 1724
* Philips: 22AV1012, 22AV1401

Most widescreen sets without any PALplus processing will switch the display format automatically between 4:3 and 16:9, based on the [[Widescreen signaling|WSS signaling bits]]. These sets will simply zoom the centre 432 lines of the 16:9 letterboxed image to fill all of the 16:9 frame, without recovering any of the extra vertical line resolution.

== See also ==
* [[Clear-Vision]] (a similar system for NTSC broadcasts)
* [[High-definition television|HDTV]]
* [[DVB]]
* [[PAL]]
* [[Broadcast television systems]]
* [[Widescreen#Television|Widescreen television]]
* [[Widescreen signaling]]

== References ==
{{reflist}}

== External links ==
* [https://www.etsi.org/deliver/etsi_i_ets/300700_300799/300731/01_60/ets_300731e01p.pdf ETSI PALplus specification]
* [https://web.archive.org/web/20160303233323/http://stoneship.org.uk/~steve/palplus.html All You Ever Wanted to Know About PALplus but were Afraid to Ask] (Archived copy)
* [http://wgpi.tsc.uvigo.es/libro/actual/palplus.htm TV Express (in Spanish)]
* {{webarchive |url=https://web.archive.org/web/20120305002124/https://www.nalanda.nitc.ac.in/industry/appnotes/Intersil/an9764.pdf |date=5 March 2012 |title=PALplus Overview}}. Intersil Corporation.
* [http://www.ahok.de/dt/palplus.html Vom Kupferstich zu PALplus (German)]
* {{webarchive |url=https://web.archive.org/web/20160303224309/https://assets.fluke.com/appnotes/it_products/B0291A-16U9509_NL_EN.pdf |date=3 March 2016 |title=PALplus}}. Fluke Corporation.
* [http://www.radiomuseum.org/forum/fernsehen_mit_format.html Fernsehen mit Format - 4:3 contra 16:9 (German)]
* {{cite web |url=https://tvark.org/?page=1613 |title=16x9 & Line-Up Cards |last=Bergstam |first=Thomas |publisher=[[TVARK]] |access-date=27 October 2021}}
* [http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31993D0424:EN:HTML SCADplus: 16:9 Action plan for the television in the 16:9 screen format - European Union]

{{Video formats}}
{{Analogue TV transmitter topics}}

[[Category:Television technology]]
[[Category:Television transmission standards]]
[[Category:Video formats]]
[[Category:German inventions]]
[[Category:1993 introductions]]
[[Category:1993 establishments in the European Union]]