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This article is about the analog standard-definition resolution. For the equivalent digital SD resolution, see576i.
Analog TV standard by nation; countries using 625-line are in blue.
Image showing the full 625 line raster containing the visible 576 line image area

625-line(orCCIR625/50) is a late 1940sEuropeananalogstandard-definition televisionresolution standard.[1][2]It consists of a 625-lineraster,with 576 lines carrying the visible image at 25interlacedframesper second. It was eventually adopted by countries using 50 Hzutility frequencyas regular TV broadcasts resumed after World War II.[3]With the introduction of color television in the 1960s,[4]it became associated with thePALandSECAManalog color systems.

A similar525-linesystem was adopted by countries using 60 Hz utility frequency (like theUS). Other systems, like375-line,405-line,441-line,455-lineand819-lineexisted, but became outdated or had limited adoption.

The modern standard-definitiondigital videoresolution576iis equivalent and can be used todigitizean analogue 625-line TV signal, or to generate a 625-line compatible analog signal.[5]

History[edit]

At the CCIRStockholmConference in July 1948 a first 625-line system with a 8 MHzchannel bandwidthwas proposed by theSoviet Union,based on 1946-48 studies[3]byMark Krivosheev.[6][7][8][9][10][11][12][13]This was initially known as theI.B.T.O.625-line system.

At a CCIRGenevameeting in July 1950, Dr. Gerber (a Swiss engineer), proposed a modified 625-line system using a 7 MHz channel bandwidth - informally known as the "Gerber Standard". The system was based on work byTelefunkenandWalter Bruch,and was supported byBelgium,Denmark,Italy,Netherlands,SwedenandSwitzerland.[3]

At a CCIR Geneva meeting in May 1951, the existingVHFbroadcast standards were standardized.[3]The older 405-line system was designatedCCIR System A,the Gerber Standard was designatedSystem B,the Belgian variantSystem Cand the I.B.T.O. standardSystem D.

In the 1960s, with the introduction ofUHFbroadcasts, new 625-line standards were adopted, again with slightly different broadcast parameters, leading to the creation of SystemsG,H,I,KandL.

Analog broadcast 625-line television standards[edit]

The followingInternational Telecommunication Unionstandardsuse 625-lines:

World analog 625-line television systems[14]
ITU System Letter Designation

B

[15][16][17][18]

C

[19][20][21]

D

[22][21][23][24]

G

[25]

H

[25]

I

[26]

K

[22][27]

 K1

L

[28][21]

N

[29][30]

Previous designation

Gerber Standard

[15][16][17][18]

Belgian 625-line system

[19][20][21]

I.B.T.O.625-line system

[22][21][23][24]
Band VHF VHF VHF UHF UHF UHF UHF VHF/UHF VHF/UHF VHF/UHF
Introduced 1950 1953 1948 1961 1961 1962 1961 1964 1961 1951
Channel bandwidth (MHz) 7 7 8 8 8 8 8 8 8 6
Video bandwidth (MHz) 5 5 6 5 5 5.5 6 6 6 4.2
Vision sound carrier separation (MHz) +5.5 +5.5 +6.5 +5.5 +5.5 +5.9996 +6.5 +6.5 -6.5 +4.5
Vestigial sideband (MHz) 0.75 0.75 0.75 0.75 1.25 1.25 0.75 1.25 1.25 0.75
Vision modulation (+, -) - + - - - - - - + -
Sound modulation (AM, FM) FM AM FM FM FM FM FM FM AM FM
Frequency of chrominance subcarrier (MHz) 4.43 none 4.43 4.43 4.43 4.43 4.43 4.43 4.43 3.58
Vision/sound power ratio 5:1 5:1 5:1 5:1 8:1
Usual color PAL/SECAM none SECAM/PAL PAL/SECAM PAL PAL SECAM/PAL SECAM SECAM PAL
Assumed display device gamma[31][14] 2.8 2.0 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8

Analog color 625-line television systems[edit]

The followinganalog televisioncolor systems were used in conjunction with the previous standards (identified by a letter after the colour system indication):

  • PALanalog color television system (ex: PAL-B, PAL-D, etc.)
  • SECAManalog color television system (ex: SECAM-D, SECAM-L, etc.)

Digital video[edit]

625-lines is sometimes mentioned when digitizing analog video, or when outputting digital video in a standard-definition analog compatible format.

See also[edit]

References[edit]

  1. ^Observer, Reflective (December 23, 2021)."Where did 625-line TV come from?".
  2. ^"Televisionen - Das Fernsehen in der UdSSR / TV in the USSR Die Geschichte des Fernsehens in Russland".www.scheida.at.
  3. ^abcd"Piet's Home-built Television".Maximus R&D.
  4. ^"Television broadcasting 1960-70: BBC 625-line services and the introduction of colour"(PDF).
  5. ^"What means 576i?".Afterdawn.com.
  6. ^""M.I. Krivosheev: participation in the development of mass TV broadcasting" - an exhibition at Ostankino TV Center ".eng.rscc.ru.
  7. ^"Mark Iosifovich Krivosheev (1922-2018)".ITU.
  8. ^On the beginning of broadcast in 625-lines 60 year s ago,625magazine (in Russian).Archived2016-03-04 at theWayback Machine
  9. ^"M.I. Krivocheev - an engineer's engineer"(PDF).EBU Technical Review.Spring 1993. pp. 27–28. Archived fromthe original(PDF)on 2004-12-30.
  10. ^"In the vanguard of television broadcasting - Professor Mark Krivocheev"(PDF).cra.ir.Archived fromthe original(PDF)on 2007-02-21.
  11. ^Observer, Reflective (2021-12-23)."Where did 625-line TV come from?".Medium.Retrieved2021-12-31.
  12. ^"625-Line Television System Origins - UK Vintage Radio Repair and Restoration Discussion Forum".www.vintage-radio.net.Retrieved2021-12-31.
  13. ^"Leader Electronics Corporation".Leader Electronics Corporation.
  14. ^abSuzuki, N.; Fukinuki, T.; Kageyama, M.; Ishikura, K.; Yoshigi, H. (January 1, 1994)."Multiplexing scheme of helper signals on bars in EDTV-II".International Broadcasting Convention - IBC '94.Vol. 1994. pp. 32–36.doi:10.1049/cp:19940723– via digital-library.theiet.org.
  15. ^ab"625-Line Television Broadcast Standards - UK Vintage Radio Repair and Restoration Discussion Forum".www.vintage-radio.net.
  16. ^ab"405 Alive - FAQ - 405-Line Television in History".www.bvws.org.uk.
  17. ^ab"The CCIR, the standards and the TV sets' market in France (1948-1985)"(PDF).
  18. ^abMagnetic Recording Handbook.Springer Science & Business Media. December 6, 2012.ISBN9789401094689– via Google Books.
  19. ^ab"Documents of the XIth Plenary Assembly - Oslo, 1966"(PDF).International Telecommunication Union. Volume V.
  20. ^ab"World Analogue Television Standards and Waveforms".August 30, 2012. Archived fromthe originalon 30 August 2012.
  21. ^abcde"World Analogue Television Standards and Waveforms".August 30, 2012. Archived fromthe originalon 30 August 2012.
  22. ^abc"Section 11A: Characteristics of systems for monochrome and colour television"(PDF).itu.int.Reportt 624-4.
  23. ^ab""M.I. Krivosheev: Participation in the development of mass TV broadcasting" - an exhibition at Ostankino TV Center ".
  24. ^ab"Mark Iosifovich Krivosheev (1922-2018)".
  25. ^abReference Data for Radio Engineers, ITT Howard W.Sams Co., New York, 1977, section 30
  26. ^"Specification of Television Standards for 625-Line System I Transmissions in the United Kingdom"(PDF).
  27. ^"World Analogue Television Standards and Waveforms".www.pembers.freeserve.co.uk.Archived fromthe originalon 30 August 2012.Retrieved12 January2022.
  28. ^Documents of the Xlth Plenary Assembly - Oslo, 1966 - Volume V - Sound Broacasting Television(PDF).International Telecommunication Union. 1967.
  29. ^"Help Guide | On TV color systems".www.sony-asia.com.
  30. ^Tecnologica, Centro de Informacion (January 19, 1999)."Informacion Tecnologica".Centro de Informacion Tecnologica – via Google Books.
  31. ^"C.C.I.R. Report 624-4 Characteristics of television systems, 1990"(PDF).
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