625 lines

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This article is about the analog standard-definition resolution. For the equivalent digital SD resolution, see 576i.
Analog TV standard by nation; countries using 625-line are in blue.

625-line (or

frames per second. It was eventually adopted by countries using 50 Hz utility frequency as regular TV broadcasts resumed after World War II.[3] With the introduction of color television in the 1960s,[4] it became associated with the PAL and SECAM
analog color systems.

A similar 525-line system was adopted by countries using 60 Hz utility frequency (like the US). Other systems, like 375-line, 405-line, 441-line, 455-line and 819-line existed, but became outdated or had limited adoption.

The modern standard-definition digital video resolution 576i is equivalent and can be used to digitize an analogue 625-line TV signal, or to generate a 625-line compatible analog signal.[5]

History

At the CCIR Stockholm Conference in July 1948 a first 625-line system with a 8 MHz channel bandwidth was proposed by the Soviet Union, based on 1946-48 studies[3] by Mark Krivosheev.[6][7][8][9][10][11][12][13] This was initially known as the I.B.T.O. 625-line system.

At a CCIR Geneva meeting 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 by Telefunken and Walter Bruch, and was supported by Belgium, Denmark, Italy, Netherlands, Sweden and Switzerland.[3]

At a CCIR Geneva meeting in May 1951, the existing VHF broadcast standards were standardized.[3] The older 405-line system was designated CCIR System A, the Gerber Standard was designated System B, the Belgian variant System C and the I.B.T.O. standard System D.

In the 1960s, with the introduction of UHF broadcasts, new 625-line standards were adopted, again with slightly different broadcast parameters, leading to the creation of Systems G, H, I, K and L.

Analog broadcast 625-line television standards

The following International Telecommunication Union standards use 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

The following analog television color systems were used in conjunction with the previous standards (identified by a letter after the colour system indication):

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

Digital video

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

  • 576i, a standard-definition television digital video mode.
  • PAL region
    , a common term regarding video games, meaning regions where the 625-lines PAL standard was traditionally used.
  • PAL/SECAM DVD
  • PAL/SECAM Video CD
  • Rec. 601, a 1982 standard for encoding interlaced analog video signals in digital video form.
  • D-1, a 1986 SMPTE component digital recording video standard.
  • D-2, a 1988 SMPTE composite digital recording video standard.

See also

References

  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. ^ a b c d "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, 625 magazine (in Russian). Archived 2016-03-04 at the Wayback Machine
  9. ^ "M.I. Krivocheev - an engineer's engineer" (PDF). EBU Technical Review. Spring 1993. pp. 27–28. Archived from the original (PDF) on 2004-12-30.
  10. ^ "In the vanguard of television broadcasting - Professor Mark Krivocheev" (PDF). cra.ir. Archived from the original (PDF) on 2007-02-21.
  11. ^ Observer, Reflective (2021-12-23). "Where did 625-line TV come from?". Medium. Retrieved 2021-12-31.
  12. ^ "625-Line Television System Origins - UK Vintage Radio Repair and Restoration Discussion Forum". www.vintage-radio.net. Retrieved 2021-12-31.
  13. ^ "Leader Electronics Corporation". Leader Electronics Corporation.
  14. ^
    doi:10.1049/cp:19940723 – via digital-library.theiet.org. {{cite journal}}: Cite journal requires |journal= (help
    )
  15. ^ a b "625-Line Television Broadcast Standards - UK Vintage Radio Repair and Restoration Discussion Forum". www.vintage-radio.net.
  16. ^ a b "405 Alive - FAQ - 405-Line Television in History". www.bvws.org.uk.
  17. ^ a b "The CCIR, the standards and the TV sets' market in France (1948-1985)" (PDF).
  18. ^
    ISBN 9789401094689
    – via Google Books.
  19. ^ a b "Documents of the XIth Plenary Assembly - Oslo, 1966" (PDF). International Telecommunication Union. Volume V.
  20. ^ a b "World Analogue Television Standards and Waveforms". August 30, 2012. Archived from the original on 30 August 2012.
  21. ^ a b c d e "World Analogue Television Standards and Waveforms". August 30, 2012. Archived from the original on 30 August 2012.
  22. ^ a b c "Section 11A: Characteristics of systems for monochrome and colour television" (PDF). itu.int. Reportt 624-4.
  23. ^ a b ""M.I. Krivosheev: Participation in the development of mass TV broadcasting" - an exhibition at Ostankino TV Center".
  24. ^ a b "Mark Iosifovich Krivosheev (1922-2018)".
  25. ^ a b Reference 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 from the original on 30 August 2012. Retrieved 12 January 2022.
  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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