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NTSC, named after the National Television System Committee,[1] is the analog television color system that was introduced in North America in 1954 and stayed in use until digital conversion. It was one of three major analog color television standards, the others being PAL and SECAM.

All the countries using NTSC are currently in the process of conversion, or have already converted to the ATSC standard, or to DVB, ISDB, or DTMB.

This page primarily discusses the NTSC color encoding system. The articles on broadcast television systems and analog television further describe frame rates, image resolution, and audio modulation.

Geographic reach

The NTSC standard was used in most of North America, western South America, Liberia, Myanmar, South Korea, Taiwan, Philippines, Japan, and some Pacific island nations and territories (see map).

Digital conversion

Most countries using the NTSC standard, as well as those using other analog television standards, have switched to, or are in process of switching to, newer digital television standards, with there being at least four different standards in use around the world. North America, parts of Central America, and South Korea are adopting or have adopted the ATSC standards, while other countries, such as Japan, are adopting or have a

All the countries using NTSC are currently in the process of conversion, or have already converted to the ATSC standard, or to DVB, ISDB, or DTMB.

This page primarily discusses the NTSC color encoding system. The articles on broadcast television systems and analog television further describe frame rates, image resolution, and audio modulation.

The NTSC standard was used in most of North America, western South America, Liberia, Myanmar, South Korea, Taiwan, Philippines, Japan, and some Pacific island nations and territories (see map).

Digital conversion

Most countries using the NTSC standard, as well as those using other analog television standards, have switched to, or are in process of switching to, newer digital television standards, with there being at least four different standards in use around the world. North America, parts of Central America, and South Korea are adopting or have adopted the ATSC standards, while other countries, such as Japan, are adopting or have adopted other standards instead of ATSC. After nearly 70 years, the majority of over-the-air NTSC transmissions in the United States ceased on January 1, 2010,[2] and by August 31, 2011[3] in Canada and most other NTSC markets.[4] The majority of NTSC transmissions ended in Japan on July 24, 2011, with the Japanese prefectures of Iwate, Miyagi, and Fukushima ending the next year.[3] After a pilot program in 2013, most full-power analog stations in Mexico left the air on ten dates in 2015, with some 500 low-power and repeater stations allowed to remain in analog until the end of 2016. Digital broadcasting allows higher-resolution television, but digital standard definition television continues to use the frame rate and number of lines of resolution established by the analog NTSC standard.

History

The first NTSC standard was developed in 1941 and had no provision for color. In 1953, a second NTSC standard was adopted, which allowed for color television broadcasting which was compatible with the existing stock of black-and-white receivers. NTSC was the first widely adopted broadcast color system and remained dominant until the 2000s, when it started to be replaced with different digital standards such as ATSC and others.

The National Television System Committee was established in 1940 by the United States Federal Communications Commission (FCC) to resolve the conflicts between companies over the introduction of a nationwide analog television system in the United States. In March 1941, the committee issued a technical standard for black-and-white television that built upon a 1936 recommendation made by the Radio Manufacturers Association (RMA). Technical advancements of the vestigial side band technique allowed for the opportunity to increase the image resolution. The NTSC selected 525 scan lines as a compromise between RCA's 441-scan line standard (already being used by RCA's NBC TV network) and Philco's and DuMont's desire to increase the number of scan lines to between 605 and 800.[5] The standard recommended a frame rate of 30 frames (images) per second, consisting of two interlaced fields per frame at 262.5 lines per field and 60 fields per second. Other sta

Most countries using the NTSC standard, as well as those using other analog television standards, have switched to, or are in process of switching to, newer digital television standards, with there being at least four different standards in use around the world. North America, parts of Central America, and South Korea are adopting or have adopted the ATSC standards, while other countries, such as Japan, are adopting or have adopted other standards instead of ATSC. After nearly 70 years, the majority of over-the-air NTSC transmissions in the United States ceased on January 1, 2010,[2] and by August 31, 2011[3] in Canada and most other NTSC markets.[4] The majority of NTSC transmissions ended in Japan on July 24, 2011, with the Japanese prefectures of Iwate, Miyagi, and Fukushima ending the next year.[3] After a pilot program in 2013, most full-power analog stations in Mexico left the air on ten dates in 2015, with some 500 low-power and repeater stations allowed to remain in analog until the end of 2016. Digital broadcasting allows higher-resolution television, but digital standard definition television continues to use the frame rate and number of lines of resolution established by the analog NTSC standard.

History

color television broadcasting which was compatible with the existing stock of black-and-white receivers. NTSC was the first widely adopted broadcast color system and remained dominant until the 2000s, when it started to be replaced with different digital standards such as ATSC and others.

The National Television System Committee was established in 1940 by the United States Federal Communications Commission (FCC) to resolve the conflicts between companies over the introduction of a nationwide analog television system in the United States. In March 1941, the committee issued a technical standard for Federal Communications Commission (FCC) to resolve the conflicts between companies over the introduction of a nationwide analog television system in the United States. In March 1941, the committee issued a technical standard for black-and-white television that built upon a 1936 recommendation made by the Radio Manufacturers Association (RMA). Technical advancements of the vestigial side band technique allowed for the opportunity to increase the image resolution. The NTSC selected 525 scan lines as a compromise between RCA's 441-scan line standard (already being used by RCA's NBC TV network) and Philco's and DuMont's desire to increase the number of scan lines to between 605 and 800.[5] The standard recommended a frame rate of 30 frames (images) per second, consisting of two interlaced fields per frame at 262.5 lines per field and 60 fields per second. Other standards in the final recommendation were an aspect ratio of 4:3, and frequency modulation (FM) for the sound signal (which was quite new at the time).

In January 1950, the committee was reconstituted to standardize color television. The FCC had briefly approved a color television standard in October 1950, which was developed by CBS.[6] The CBS system was incompatible with existing black-and-white receivers. It used a rotating color wheel, reduced the number of scan lines from 525 to 405, and increased the field rate from 60 to 144, but had an effective frame rate of only 24 frames per second. Legal action by rival RCA kept commercial use of the system off the air until June 1951, and regular broadcasts only lasted a few months before manufacture of all color television sets was banned by the Office of Defense Mobilization in October, ostensibly due to the Korean War.[7] CBS rescinded its system in March 1953,[8] and the FCC replaced it on December 17, 1953, with the NTSC color standard, which was cooperatively developed by several companies, including RCA and Philco.[9]

In December 1953, the FCC unanimously approved what is now called the NTSC color television standard (later defined as RS-170a). The compatible color standard retained full backward compatibility with then-existing black-and-white television sets. Color information was added to the black-and-white image by introducing a color subcarrier of precisely 315/88 MHz (usually described as 3.579545 MHz±10 Hz[10] or about 3.58 MHz). The precise frequency was chosen so that horizontal line-rate modulation components of the chrominance signal fall exactly in between the horizontal line-rate modulation components of the luminance signal, thereby enabling the chrominance signal to be filtered out of the luminance signal with minor degradation of the luminance signal. (Also, minimize the visibility on existing sets that do not filter it out.) Due to limitations of frequency divider circuits at the time the color standard was promulgated, the color subcarrier frequency was constructed as composite frequency assembled from small integers, in this case 5×7×9/(8×11) MHz.[11] The horizontal line rate was reduced to approximately 15,734 lines per second (3.579545×2/455 MHz = 9/572 MHz) from 15,750 lines per second, and the frame rate was reduced to 30/1.001 ≈ 29.970 frames per second (the horizontal line rate divided by 525 lines/frame) from 30 frames per second. These changes amounted to 0.1 percent and were readily tolerated by then-existing television receivers.[12][13]

The first publicly announced network television broadcast of a program using the NTSC "compatible color" system was an episode of NBC's Kukla, Fran and Ollie on August 30, 1953, although it was viewable in color only at the network's headquarters.[14] The first nationwide viewing of NTSC color came on the following January 1 with the coast-to-coast broadcast of the Tournament of Roses Parade, viewable on prototype color receivers at special presentations across the country. The first color NTSC television camera was the RCA TK-40, used for experimental broadcasts in 1953; an improved version, the TK-40A, introduced in March 1954, was the first commercially available color television camera. Later that year, the improved TK-41 became the standard camera used throughout much of the 1960s.

The NTSC standard has been adopted by other countries, including most of the Americas and Japan.

With the advent of digital television, analog broadcasts are being phased out. Most US NTSC broadcasters were required by the FCC to shut down their analog transmitters in 2009. Low-power stations, Class A stations and translators were required to shut down by 2015.

NTSC color encoding is used with the System M television signal, which consists of ​301.001 (approximately 29.97) interlaced frames of video per second. Each frame is composed of two fields, each consisting of 262.5 scan lines, for a total of 525 scan lines. 486 scan lines make up the visible raster. The remainder (the vertical blanking interval) allow for vertical synchronization and retrace. This blanking interval was originally designed to simply blank the electron beam of the receiver's CRT to allow for the simple analog circuits and slow vertical retrace of early TV receivers. However, some of these lines may now contain other data such as closed captioning and vertical interval timecode (VITC). In the complete raster (disregarding half lines due to interlacing) the even-numbered scan lines (every other line that would be even if counted in the video signal, e.g. {2, 4, 6, ..., 524}) are drawn in the first field, and the odd-numbered (every other line that would be odd if counted in the video signal, e.g. {1, 3, 5, ..., 525}) are drawn in the second field, to yield a flicker-free image at the field refresh frequency of ​601.001 Hz (approximately 59.94 Hz). For comparison, 576i systems such as PAL-B/G and SECAM use 625 lines (576 visible), and so have a higher vertical resolution, but a lower temporal resolution of 25 frames or 50 fields per second.

The NTSC field refresh frequency in the black-and-white system originally exactly matched the nominal 60 Hz frequency of alternating current power used in the United States. Matching the field refresh rate to the power source avoided intermodulation (also called beating), which produces rolling bars on the screen. Synchronization of the refresh rate to the power incidentally helped frequency of alternating current power used in the United States. Matching the field refresh rate to the power source avoided intermodulation (also called beating), which produces rolling bars on the screen. Synchronization of the refresh rate to the power incidentally helped kinescope cameras record early live television broadcasts, as it was very simple to synchronize a film camera to capture one frame of video on each film frame by using the alternating current frequency to set the speed of the synchronous AC motor-drive camera. When color was added to the system, the refresh frequency was shifted slightly downward by 0.1% to approximately 59.94 Hz to eliminate stationary dot patterns in the difference frequency between the sound and color carriers, as explained below in "Color encoding". By the time the frame rate changed to accommodate color, it was nearly as easy to trigger the camera shutter from the video signal itself.

The actual figure of 525 lines was chosen as a consequence of the limitations of the vacuum-tube-based technologies of the day. In early TV systems, a master voltage-controlled oscillator was run at twice the horizontal line frequency, and this frequency was divided down by the number of lines used (in this case 525) to give the field frequency (60 Hz in this case). This frequency was then compared with the 60 Hz power-line frequency and any discrepancy corrected by adjusting the frequency of the master oscillator. For interlaced scanning, an odd number of lines per frame was required in order to make the vertical retrace distance identical for the odd and even fields, which meant the master oscillator frequency had to be divided down by an odd number. At the time, the only practical method of frequency division was the use of a chain of vacuum tube multivibrators, the overall division ratio being the mathematical product of the division ratios of the chain. Since all the factors of an odd number also have to be odd numbers, it follows that all the dividers in the chain also had to divide by odd numbers, and these had to be relatively small due to the problems of thermal drift with vacuum tube devices. The closest practical sequence to 500 that meets these criteria was 3×5×5×7=525. (For the same reason, 625-line PAL-B/G and SECAM uses 5×5×5×5, the old British 405-line system used 3×3×3×3×5, the French 819-line system used 3×3×7×13 etc.)

The original 1953 color NTSC specification, still part of the United States Code of Federal Regulations, defined the colorimetric values of the system as follows:[15]

See also

Notes

  1. ^ National Television System Committee (1951–1953), [Report and Reports of Panel No. 11, 11-A, 12-19, with Some supplementary references cited in the Reports, and the Petition for adoption of transmission standards for color television before the Federal Communications Commission, n.p., 1953], 17 v. illus., diagrs., tables. 28 cm. LC Control No.:54021386 Library of Congress Online Catalog
  2. ^ Digital Television. FCC.gov. Retrieved on 2014-05-11.
  3. ^ a b DTV and Over-the-Air Viewers Along U.S. Borders. FCC.gov. Retrieved on 2014-05-11.
  4. ^ Canada... PAL or NTSC?. VideoHelp Forum Retrieved on 2015-01-23.
  5. ^ What actually occurred was the RCA TG-1 synch generator system was upgraded from 441 lines per frame, 220.5 lines per field, interlaced, to 525 lines per frame 262.5 lines per field, also interlaced, with minimal additional changes, particularly not those affecting the vertical interval, which, in the extant RCA system, included serrated equalizing pulses bracketing the vertical sync pulse, itself being serrated. For RCA/NBC, this was a very simple change from a 26,460 Hz master oscillator to a 31,500 Hz master oscillator, and minimal additional changes to the generator's divider chain. The equalizing pulses and the serration of the vertical sync pulse were necessary because of the limitations of the extant TV receiver video/sync separation technology, thought to be necessary because the sync was transmitted in band with the video, although at a quite different DC level. The early TV sets did not possess a DC restorer circuit, hence the need for this level of complexity. In-studio monitors were provided with separate horizontal and vertical sync, not composite synch and certainly not in-band synch (possibly excepting early color TV monitors, which were often driven from the output of the station's colorplexer).
  6. ^ A third line sequential system from Color Television Inc. (CTI) was also considered. The CBS and final NTSC systems were called field-sequential and dot-sequential systems, respectively.
  7. ^ "Color TV Shelved As a Defense Step", The New York Times, October 20, 1951, p. 1. "Action of Defense Mobilizer in Postponing Color TV Poses Many Question for the Industry", The New York Times, October 22, 1951, p. 23. "TV Research Curb on Color Avoided", The New York Times, October 26, 1951. Ed Reitan, CBS Field Sequential Color System Archived 2010-01-05 at the Wayback Machine, 1997. A variant of the CBS system was later used by NASA to broadcast pictures of astronauts from space.
  8. ^ "CBS Says Confusion Now Bars Color TV," Washington Post, March 26, 1953, p. 39.
  9. ^ "F.C.C. Rules Color TV Can Go on Air at Once", The New York Times, December 19, 1953, p. 1.
  10. ^ "73.682" (PDF). www.govinfo.gov. FCC. Retrieved 22 January 2019.
  11. ^ The master oscillator is 315/22 = 14.31818 MHz, from which the 3.579545 color burst frequency is obtained by dividing by four; and the 31 kHz horizontal drive and 60 Hz vertical drive are also synthesized from that frequency. This facilitated a conversion to color of the then common, but monochrome, RCA TG-1 synchronizing generator by the simple expedient of adding-on an external 14.31818 MHz temperature-controlled oscillator and a few dividers, and inputting the outputs of that chassis to certain test points within the TG-1, thereby disabling the TG-1's own 31500 Hz reference oscillator.
  12. ^ "Choice of Chrominance Subcarrier Frequency in the NTSC Standards," Abrahams, I.C., Proc. IRE, Vol. 42, Issue 1, p.79–80
  13. ^ "The Frequency Interleaving Principle in the NTSC Standards," Abrahams, I.C., Proc. IRE, vol. 42, Issue 1, p. 81–83
  14. ^ "NBC Launches First Publicly-Announced Color Television Show", Wall Street Journal, August 31, 1953, p. 4.
  15. ^ 47 CFR § 73.682 (20) (iv)
  16. ^ DeMarsh, Leroy (1993): TV Display Phosphors/Primaries — Some History. SMPTE Journal, December 1993: 1095–1098. doi:10.5594/J01650
  17. ^ a b c International Telecommunications Union Recommendation ITU-R 470-6 (1970–1998): Conventional Television Systems, Annex 2.
  18. ^ Society of Motion Picture and Television Engineers (1987–2004): Recommended Practice RP 145-2004. Color Monitor Colorimetry.
  19. ^ Society of Motion Picture and Television Engineers (1994, 2004): Engineering Guideline EG 27-2004. Supplemental Information for SMPTE 170M and Background on the Development of NTSC Color Standards, pp. 9
  20. ^ Advanced Television Systems Committee (2003): ATSC Direct-to-Home Satellite Broadcast Standard Doc. A/81, pp.18
  21. ^ European Broadcasting Union (1975) Tech. 3213-E.: E.B.U. Standard for Chromaticity Tolerances for Studio Monitors.
  22. ^ Poynton's Color FAQ by Charles Poynton
  23. ^ CCIR Report 308-2 Part 2 Chapter XII – Characteristics of Monochrome Television Systems (1970 edition).
  24. ^ VWestlife's Camcorder Tests & More (6 January 2010). "Recording PAL and 625-line 50 Hz NTSC video on a U.S. VCR" – via YouTube.
  25. ^ "Variants of NTSC standard". 2018-03-25.
  26. ^ Jain, Anal K., Fundamentals of Digital Image Processing, Upper Saddle River, NJ: Prentice Hall, 1989, p. 82.
  27. ^ "LM1881 Video Sync Separator" (PDF). 2006-03-13. Archived from the original (PDF) on 2006-03-13.
  28. ^ Waveform Mons & Vectorscopes. Danalee.ca. Retrieved on 2014-05-11.
  29. ^ SMPTE EBU timecode by Phil Rees. Philrees.co.uk. Retrieved on 2014-05-11.
  30. ^ Technical Introduction to Timecode Archived 2007-07-10 at the Wayback Machine. Poynton.com. Retrieved on 2014-05-11.
  31. ^ Tools | The History Project. Experimentaltvcenter.org. Retrieved on 2014-05-11.
  32. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax Michael Hegarty; Anne Phelan; Lisa Kilbride (1 January 1998). Classrooms for Distance Teaching and Learning: A Blueprint. Leuven University Press. pp. 260–. ISBN 978-90-6186-867-5.
  33. ^ "BBC's All-Digital TV Output Plans 'On Course'". 9 March 2016.
  34. ^ Canadian Radio-television and Telecommunications Commission (CRTC) Press release May 2007 Archived 2007-05-19 at the Wayback Machine
  35. ^ "Archived copy". Archived from the original on September 28, 2019. Retrieved February 8, 2020.CS1 maint: archived copy as title (link)
  36. ^ Indotel. "Televisión Digital en RD". www.indotel.gob.do.
  37. ^ Hester, Lisa (July 6, 2004). "Mexico To Adopt The ATSC DTV Standard". Advanced Television Systems Committee. Archived from the original on June 6, 2014. Retrieved June 4, 2013. On July 2 the Government of Mexico formally adopted the ATSC Digital Television (DTV) Standard for digital terrestrial television broadcasting.
  38. ^ Dibble, Sandra (May 30, 2013). "New turn for Tijuana's transition to digital broadcasting". San Diego Union-Tribune. Archived from the original on September 6, 2013. Retrieved June 4, 2013.
  39. ^ "DOF - Diario Oficial de la Federación". dof.gob.mx. Archived from the original on January 21, 2018. Retrieved March 16, 2018.
  40. ^ Philip J. Cianci (9 January 2012). High Definition Television: The Creation, Development and Implementation of HDTV Technology. McFarland. pp. 302–. ISBN 978-0-7864-8797-4.
  41. ^ "Philippines to start digital TV shift in 2019". NexTV Asia-Pacific. Archived from the original on 2015-02-09. Retrieved 2014-10-27.
  42. ^ Cabuenas, Jon Viktor D. (2017-02-14). "Gov't wants analog TV switched off by 2023". GMA News Online. Retrieved December 6, 2018.
  43. ^ Dela Paz, Chrisee (14 February 2017). "Hardware boom comes with PH shift to digital TV". Rappler. Retrieved January 21, 2019.
  44. ^ Mariano, Keith Richard D. (16 February 2017). "Broadcasters commit to digital TV switch by 2023". BusinessWorld. Retrieved January 21, 2019.
  45. ^ Esmael, Maria Lisbet K. (7 October 2018). "Govt on course to hit 2023 full digital TV transition". The Manila Times. Retrieved January 21, 2019.
  46. ^ Mercurio, Richmond (4 October 2018). "Digital TV shift by 2023 pushing through — DICT". The Philippine Star. Retrieved January 21, 2019.
  47. ^ https://web.archive.org/web/20090210110616/http://commerce.senate.gov/public/index.cfm?FuseAction=PressReleases.Detail&PressRelease_Id=84452e41-ca68-4aef-b15f-bbca7bab2973. Archived from