Editing PAL (section)

== PAL broadcast systems ==
The PAL colour system is usually used with a video format that has 625 lines per frame (576 visible lines, the rest being used for other information such as sync data and captioning) and a [[refresh rate]] of 50&nbsp;[[Interlaced video|interlaced]] fields per second (compatible with 25&nbsp;full frames per second), such systems being '''B''', '''G''', '''H''', '''I''', and '''N''' (see [[Broadcast television systems#ITU identification scheme|broadcast television system]]s for the technical details of each format).

This ensures video interoperability. However, as some of these standards ('''B/G/H''', '''I''' and '''D/K''') use different sound carriers (5.5&nbsp;MHz, 6.0&nbsp;MHz and 6.5&nbsp;MHz respectively), it may result in a video image without audio when viewing a signal broadcast over the air or cable. Some countries in [[Eastern Europe]] which formerly used [[SECAM]] with systems '''D''' and '''K''' have switched to PAL while leaving other aspects of their video system the same, resulting in the different sound carrier. Instead, other European countries have changed completely from SECAM-D/K to PAL-B/G.<ref name="ebu">{{cite web |title=Changes to the terrestrial television systems in Central and East European countries |url=http://tech.ebu.ch/docs/i/i033.pdf |access-date=11 September 2010 |publisher=[[European Broadcasting Union|EBU]] |archive-date=17 July 2011 |archive-url=https://web.archive.org/web/20110717135202/http://tech.ebu.ch/docs/i/i033.pdf |url-status=live}}</ref>

The PAL-N system has a different sound carrier, and also a different colour subcarrier, and decoding on incompatible PAL systems results in a black-and-white image without sound.

The PAL-M system has a different sound carrier and a different colour subcarrier, and does not use 625 lines or 50&nbsp;frames/second. This would result in no video or audio at all when viewing a European signal.

{| class="wikitable"
|+ Differences between PAL variants<ref name="auto"/>
|- style="font-weight:bold;"
! style="font-weight:normal;" |
! | PAL B
! | PAL G, H
! | PAL I
! | PAL D/K, L
! | PAL N
! | PAL M
|-
| style="font-weight:bold;" | [[ITU radio bands|Transmission band]]
| [[Very high frequency|VHF]]
| [[Ultra high frequency|UHF]]
| colspan="4" | VHF/UHF
|-
| style="font-weight:bold;" | [[Field (video)|Fields]]
| colspan="5" | 50
| 60
|-
| style="font-weight:bold;" | [[Scan lines]]
| colspan="5" | [[625 lines|625]]
| [[525 lines|525]]
|-
| style="font-weight:bold;" | [[Raster scan|Active lines]]
| colspan="5" | 576
| 480
|-
| style="font-weight:bold;" | [[Bandwidth (signal processing)|Channel bandwidth]]
| 7&nbsp;MHz
| colspan="3" | 8&nbsp;MHz
| colspan="2" | 6&nbsp;MHz
|-
| style="font-weight:bold;" | [[Video bandwidth]]
| colspan="2" | 5.0&nbsp;MHz
| 5.5&nbsp;MHz
| 6.0&nbsp;MHz
| colspan="2" | 4.2&nbsp;MHz
|-
| style="font-weight:bold;" | Vision/Sound carrier spacing
| colspan="2" | 5.5&nbsp;MHz
| 6.0&nbsp;MHz
| 6.5&nbsp;MHz
| colspan="2" | 4.5&nbsp;MHz
|-
| style="font-weight:bold;" | Colour [[Subcarrier]]
| colspan="4" | 4.43361875&nbsp;MHz
| 3.58205625&nbsp;MHz
| 3.575611&nbsp;MHz
|-
| style="font-weight:bold;" | Assumed Receiver<br />[[Gamma correction]]
| colspan="5" | 2.8
| 2.2
|}

=== System A ===
The BBC tested their pre-war (but still broadcast until 1985) [[405-line television system|405-line]] monochrome system ([[CCIR System A]]) with all three colour standards including PAL, before the decision was made to abandon 405 and transmit colour on 625/[[CCIR System I|System I]] only.

=== PAL-B/G/D/K/I ===
Many countries have turned off analogue transmissions, so the following does not apply anymore, except for using devices which output RF signals, such as [[Digital video recorder|video recorder]]s.

The majority of countries using or having used PAL have television standards with 625 lines and 50&nbsp;fields per second. Differences concern the audio carrier frequency and channel bandwidths. The variants are:
* [[CCIR System B|Standards B]]/[[CCIR System G|G]] are used in most of Western Europe, former Yugoslavia, South Asia, Thailand, Australia, and New Zealand
* [[CCIR System I|Standard I]] in the UK, Ireland, Hong Kong, South Africa, and Macau
* [[CCIR System D|Standards D]]/[[CCIR System K|K]] (along with SECAM usually) in most of Central and Eastern Europe and mainland China.

Systems B and G are similar. System B specifies 7&nbsp;MHz channel bandwidth, while System G specifies 8&nbsp;MHz channel bandwidth. Australia and China used Systems B and D respectively for VHF and UHF channels. Similarly, Systems D and K are similar except for the bands they use: System D is only used on VHF, while System K is only used on UHF. Although System I is used on both bands, it has only been used on UHF in the United Kingdom.

=== PAL-L ===
The PAL-L (Phase Alternating Line with [[CCIR System L]] broadcast system) standard uses the same video system as PAL-B/G/H (625 lines, 50&nbsp;Hz field rate, 15.625&nbsp;kHz line rate), but with a larger 6&nbsp;MHz video bandwidth rather than 5.5&nbsp;MHz and moving the audio subcarrier to 6.5&nbsp;MHz. An 8&nbsp;MHz channel spacing is used for PAL-L, to maintain compatibility with System L channel spacings.

=== PAL-N (Argentina, Paraguay and Uruguay){{Anchor|PAL-N}} ===
The PAL-N standard was created in [[Argentina]], through Resolution No. 100 ME/76,<ref>{{cite web |url=http://www.palermo.edu/ingenieria/TVDIGITALPOSGRADO/3.pdf |title=La TV se muda |author= |access-date=3 April 2024 |language=Spanish |archive-date=6 October 2024 |archive-url=https://web.archive.org/web/20241006175840/http://www.palermo.edu/ingenieria/TVDIGITALPOSGRADO/3.pdf |url-status=live}}</ref> which determined the creation of a study commission for a national color standard. The commission recommended using PAL under [[CCIR System N]] that [[Paraguay]] and [[Uruguay]] also used. It employs the 625 line/50&nbsp;field per second waveform of PAL-B/G, D/K, H, and I, but on a 6&nbsp;MHz channel with a chrominance subcarrier frequency of 3.582056&nbsp;MHz (917/4*H) similar to NTSC (910/4*H).<ref name="auto"/> On the studio production level, standard PAL cameras and equipment were used, with video signals then transcoded to PAL-N for broadcast.<ref>{{cite book |last1=Iazbec |url=https://books.google.com/books?id=UGTKzPeALYYC&dq=PAL-N+%28Argentina%2C+Paraguay+and+Uruguay%29&pg=PA341 |title=Estudio de las tecnicas de transcodificacion de señales de television PAL-B / PAL-N |last2=Soria |last3=Tulli |last4=Gonzalez |date=1999 |publisher=Centro de Informacion Tecnologica |volume=10 |pages=341–349 |language=es |issue=4 |access-date=4 April 2024 |archive-date=6 October 2024 |archive-url=https://web.archive.org/web/20241006175837/https://books.google.com/books?id=UGTKzPeALYYC&dq=PAL-N+%28Argentina%2C+Paraguay+and+Uruguay%29&pg=PA341#v=onepage&q=PAL-N%20(Argentina%2C%20Paraguay%20and%20Uruguay)&f=false |url-status=live}}</ref> This allows 625 line, 50&nbsp;frames per second video to be broadcast in a 6&nbsp;MHz channel, at some cost in [[Television lines|horizontal resolution]].

=== PAL-M (Brazil) ===
{{Main|PAL-M}}

In Brazil, PAL is used in conjunction with the 525 line, 60&nbsp;field/s [[CCIR System M]], using (very nearly) the NTSC colour subcarrier frequency. Exact colour subcarrier frequency of PAL-M is 3.575611&nbsp;MHz, or 227.25 times System M's horizontal scan frequency. Almost all other countries using system M use NTSC.

The PAL colour system (either baseband or with any RF system, with the normal 4.43&nbsp;MHz subcarrier unlike PAL-M) can also be applied to an NTSC-like [[525 lines|525-line]] picture to form what is often known as "PAL 60" (sometimes "PAL 60/525", "Quasi-PAL" or "Pseudo PAL"). PAL-M (a broadcast standard) however should not be confused with "PAL 60" (a video playback system—see below).