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343-line television system

From Wikipedia, the free encyclopedia

Iconoscope television cameras at NBC in 1937.  Eddie Albert and Grace Brandt reprised their radio show, The Honeymooners-Grace and Eddie Show for television.
Iconoscope television cameras at NBC in 1937. Eddie Albert and Grace Brandt reprised their radio show, The Honeymooners-Grace and Eddie Show for television.

343-line is the number of scan lines in some early electronic monochrome analog television systems. Systems with this number of lines were used with 30 interlaced frames per second the United States by from 1935 to 1938,[1][2][3][4][5][6][7][8] and with 25 interlaced frames per second in the Soviet Union from 1937 onwards.[7][9] A similar system was under development in Poland in 1939.

TV cameras where based on the iconoscope, the primary camera tube used in American broadcasting from 1936 until 1946, when it was replaced by the image orthicon tube.[10][11] Earlier cameras used special spotlights or spinning disks to capture light from a single very brightly lit spot, and were not suitable for broadcasting of outdoor live events.

This early standard was soon replaced by 441-line systems.

United States

343-line broadcasts where introduced by RCA and NBC on November 6, 1936.[1][2][3] Tests started the previous year from New York City (W2XF on the Empire State Building[4]), where NBC converted a radio studio in the Rockefeller Center for television use.[5]

Several prototype TV sets were produced by RCA in 1936,[12] but none was available commercially.[5] Broadcasts were limited to public demonstrations in New York City (RCA)[1][2][3] and Philadelphia (Philco) - to be exact, Philco demonstrated a 345-line system, but in practice both systems were identical.[13][14][15][16][17][18]

The 343-line system was proposed for FCC approval by the Radio Manufacturers Association (RMA) on December 1937.[6] Broadcasts were phased out the following year, in favor of a 441-line system.

Technical details:[3][7][8]

System Lines Frame rate Field Frequency Interlace Channel bandwidth Visual bandwidth Sound offset Vision mod. Sound mod. Aspect Ratio Line frequency
343-line 343 30 60 Hz 2:1 6 MHz 3.29 MHz 3 Neg. AM 4:3 10290 Hz

Soviet Union

A a similar 343-line system was tested in the Soviet Union (Moscow) from 1937 onwards.[7][9] RCA provided broadcast equipment and documentation for the TV sets,[7] that were then produced locally.[9] The system was adapted for 50Hz mains electricity, with a field rate of 50hz. The first experimental transmissions happened on March 9, 1937 followed by regular broadcasts on December 31, 1938.[7]

Poland

In 1939 a 343-line system was under development in Poland, publicly demonstrated during the Warsaw Radio Exhibition on August. Regular operations were planned for the beginning of 1940, but work stopped due to the outbreak of World War II.

References

  1. ^ a b c "Recent Progress in Television Technique" (PDF). Proceedings of the Radio Club of America. 17, No.1 (February). 1940.
  2. ^ a b c "RCA Displays 343-Line TV". June 27, 2017.
  3. ^ a b c d Marshall, Paul (2011). Inventing Television: Transnational Networks of Co-operation and Rivalry, 1870-193 (PDF). University of Manchester.
  4. ^ a b "Radio-News-1937-10" (PDF).
  5. ^ a b c "RCA's Television Field Trials". www.earlytelevision.org.
  6. ^ a b Huff, W. A. Kelly (June 23, 2001). Regulating the Future: Broadcasting Technology and Governmental Control. Greenwood Publishing Group. ISBN 9780313314681 – via Google Books.
  7. ^ a b c d e f "RCA's Russian Television Connection". www.earlytelevision.org.
  8. ^ a b Herbert, Stephen (June 23, 2004). A History of Early Television. Taylor & Francis. ISBN 9780415326674 – via Google Books.
  9. ^ a b c "TK-1". www.earlytelevision.org.
  10. ^ "R.C.A. Officials Continue to Be Vague Concerning Future of Television". The Washington Post. 1936-11-15.
  11. ^ Abramson, Albert (2003). The history of television, 1942 to 2000. McFarland. p. 18. ISBN 978-0-7864-1220-4. Retrieved 2010-01-10.
  12. ^ "Early Electronic Television - RCA". Early Television Museum.
  13. ^ "Philco Television" (PDF). Radio Engineering (September): 9. 1936.
  14. ^ "Early Philco Television Development – Philco Library".
  15. ^ Murray, Albert (1938). "RMA Completes Television Standards" (PDF). Electronics (July): 28.
  16. ^ "The Deseret News - Google News Archive Search". news.google.com.
  17. ^ "Network TV". www.aes-media.org.
  18. ^ Abramson, Albert (June 27, 1955). "Electronic Motion Pictures". University of California Press – via Google Books.
This page was last edited on 27 July 2022, at 02:40
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