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{{Short description|Analog television system}}
[[File:PAL-NTSC-SECAM.svg|thumb|300px|upright=1.2|Analog television encoding systems by nation; NTSC ({{ font color | green | green }}), SECAM ({{ font color | #ff7700 | orange }}), and PAL ({{ font color | blue | blue }})]]

'''NTSC''' (from '''National Television System Committee''') is the first American standard for [[Engineering:Analog television|analog television]], published in 1941.<ref name="name">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 [http://catalog.loc.gov/cgi-bin/Pwebrecon.cgi?DB=local&PAGE=First Library of Congress Online Catalog]</ref> In 1961, it was assigned the designation '''[[CCIR System M|System M]]'''. It is also known as '''EIA''' standard.<ref>{{cite web|url=https://www.manualslib.com/manual/355825/Canon-Es8400v.html?page=72#manual|title=Canon ES8400V Instruction Manual, page 72|publisher=[[Company:Canon Inc.|Canon]]|access-date=October 11, 2023}}</ref>

In 1953, a second NTSC standard was adopted, which allowed for [[Engineering:Color television|color television]] broadcast compatible with the existing stock of black-and-white receivers. It is one of three major color formats for analog television, the others being [[Engineering:PAL|PAL]] and [[Engineering:SECAM|SECAM]]. ''NTSC color'' is usually associated with the System M; this combination is sometimes called NTSC II.<ref>{{cite web|url=https://ieeexplore.ieee.org/document/5356650|title= Engineers and Electrons: A Century of Electrical Progress (chapter list)|doi= 10.1109/9780470616321.ch9|access-date=October 11, 2023}}</ref><ref>{{cite web|url=https://www.provideocoalition.com/10-years-ago-the-analog-shutoff/|title=10 Years Ago: The Analog Shutoff|first=Adam|last=Wilt|website=provideocoalition.com|date=June 12, 2019|access-date=October 11, 2023}}</ref> The only other [[Engineering:Broadcast television systems|broadcast television system]] to use NTSC color was the [[Engineering:NTSC-J|System J]]. Brazil used System M with PAL color. Vietnam, Cambodia and Laos used System M with SECAM color.

The NTSC/System M standard was used in most of the [[Earth:Americas|Americas]] (except Argentina, Brazil, Paraguay, and Uruguay), Myanmar, South Korea, Taiwan, Philippines, Japan, and some Pacific Islands nations and territories (see map).

Since the introduction of digital sources (ex: DVD) the term '''NTSC''' has been used to refer to digital formats with number of active lines between 480 and 487 having 30 or 29.97 frames per second rate, serving as a digital shorthand to System M. The so-called ''NTSC-Film standard'' has a digital standard resolution of 720&nbsp;×&nbsp;480 pixel for [[Engineering:DVD-Video|DVD-Video]]s, 480&nbsp;×&nbsp;480 pixel for [[Engineering:Super Video CD|Super Video CD]]s (SVCD, Aspect Ratio: 4:3) and 352&nbsp;×&nbsp;240 pixel for [[Engineering:Video CD|Video CD]]s (VCD).<ref>''[http://www.paradiso-design.net/videostandards_en.html#ntsc NTSC (National Television System Committee)]'' in ''Television Standards - formats and techniques'' by Raffael Amadeus Trappe, 2013.</ref> The [[Engineering:Digital video|digital video]] (DV) camcorder format that is equivalent to NTSC is 720&nbsp;×&nbsp;480 pixels.<ref name="NTSC PCMag">''[https://www.pcmag.com/encyclopedia/term/ntsc NTSC]'' in PCMag Encyclopedia</ref> The [[Engineering:Digital television|digital television]] (DTV) equivalent is 704&nbsp;×&nbsp;480 pixels.<ref name="NTSC PCMag" />

== History ==

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 [[Physics:Single-sideband modulation#Vestigial sideband (VSB)|vestigial side band]] technique allowed for the opportunity to increase the image resolution. The NTSC selected 525&nbsp;scan lines as a compromise between [[Company:RCA|RCA]]'s [[Engineering:441-line television system#United States|441-scan line]] standard (already being used by RCA's NBC TV network) and [[Company:Philco|Philco]]'s and DuMont's desire to increase the number of scan lines to between 605 and 800.<ref>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|colorplexer]]).</ref> The standard recommended a [[Frame rate|frame rate]] of 30&nbsp;frames (images) per second, consisting of two [[Interlaced video|interlace]]d [[Engineering:Field (video)|fields]] per frame at 262.5&nbsp;lines per field and 60&nbsp;fields per second. Other standards in the final recommendation were an [[Aspect ratio (image)|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 [[Engineering:Color television|color television]]. The FCC had briefly approved a [[Engineering:405-line television system#United States 405-line field-sequential color system|405-line]] [[Engineering:Field-sequential color system|field-sequential]] color television standard in October 1950, which was developed by CBS.<ref>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.</ref> The CBS system was incompatible with existing black-and-white receivers. It used a rotating color wheel, reduced the number of [[Engineering:Scan line|scan line]]s from 525 to 405, and increased the field rate from 60 to 144, but had an effective [[Frame rate|frame rate]] of only 24&nbsp;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.<ref>"Color TV Shelved As a Defense Step", ''{{wipe|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, [http://novia.net/~ereitan/Color_Sys_CBS.html CBS Field Sequential Color System] {{webarchive |url=https://web.archive.org/web/20100105183213/http://novia.net/~ereitan/Color_Sys_CBS.html |date=January 5, 2010}}, 1997. A variant of the CBS system was later used by [[Organization:NASA|NASA]] to broadcast pictures of astronauts from space.</ref> CBS rescinded its system in March 1953,<ref>"CBS Says Confusion Now Bars Color TV", ''{{wipe|The Washington Post}}'', March 26, 1953, p. 39.</ref> 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.<ref>"F.C.C. Rules Color TV Can Go on Air at Once", ''The New York Times'', December 19, 1953, p. 1.</ref>

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 [[Engineering:Subcarrier|subcarrier]] of precisely 315/88&nbsp;MHz (usually described as 3.579545&nbsp;MHz±10&nbsp;Hz).<ref name="73.682">{{cite web |title=73.682 |url=https://www.govinfo.gov/content/pkg/CFR-2018-title47-vol4/pdf/CFR-2018-title47-vol4-sec73-682.pdf |access-date=January 22, 2019 |website=Govinfo.gov |publisher=FCC}}</ref>  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, such that the chrominance signal could easily be filtered out of the luminance signal on new television sets, and that it would be minimally visible in existing televisions. Due to limitations of [[Engineering:Frequency divider|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)&nbsp;MHz.<ref>The master oscillator is 315/22 = 14.31818&nbsp;MHz, from which the 3.579545 color burst frequency is obtained by dividing by four; and the 31&nbsp;kHz horizontal drive and 60&nbsp;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&nbsp;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&nbsp;Hz reference oscillator.</ref>  The horizontal line rate was reduced to approximately 15,734 lines per second (3.579545×2/455&nbsp;MHz = 9/572&nbsp;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.<ref>"Choice of Chrominance Subcarrier Frequency in the NTSC Standards", Abrahams, I.C., Proc. IRE, Vol. 42, Issue 1, p.79–80</ref><ref>"The Frequency Interleaving Principle in the NTSC Standards", Abrahams, I.C., Proc. IRE, vol. 42, Issue 1, p. 81–83</ref>

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.<ref>"NBC Launches First {{Sic|?|hide=y|Publicly|-}}Announced Color Television Show", ''Wall Street Journal'', August 31, 1953, p. 4.</ref> 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 [[Engineering:Professional video camera|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 some in the [[Earth:Americas|Americas]] and {{wipe|Japan}}.

With the advent of [[Engineering:Digital television|digital television]], analog broadcasts were largely phased out. Most US NTSC broadcasters were required by the FCC to shut down their analog transmitters by February 17, 2009, however this was later moved to June 12, 2009. [[Physics:Low-power broadcasting|Low-power stations]], Class A stations and [[Engineering:Broadcast relay station|translators]] were required to shut down by 2015, although an FCC extension allowed some of those stations operating on Channel 6 to operate until July 13, 2021.<ref>{{cite web |title=Media Bureau Reminds LPTV/TV Translators of Digital Transition Date (DA/FCC #: DA-20-724) |url=https://docs.fcc.gov/public/attachments/DA-20-724A1.pdf |website=docs.fcc.gov |publisher=Federal Communications Commission |access-date=January 17, 2021}}</ref> The remaining Canadian analog TV transmitters, in markets not subject to the mandatory transition in 2011, were scheduled to be shut down by January 14, 2022, under a schedule published by Innovation, Science and Economic Development Canada in 2017; however the scheduled transition dates have already passed for several stations listed that continue to broadcast in analog (e.g. CFJC-TV Kamloops, which has not yet transitioned to digital, is listed as having been required to transition by November 20, 2020).<ref>{{cite web|url=https://www.ic.gc.ca/eic/site/smt-gst.nsf/vwapj/DTV-transition-schedule2017.pdf/$FILE/DTV-transition-schedule2017.pdf|title=Digital Television (DTV) Transition Schedule|publisher=Innovation, Science and Economic Development Canada|date=April 2017|access-date=July 22, 2021}}</ref>

== Digital conversion ==
Most countries using the NTSC standard, as well as those using other [[Engineering:Analog television#Standards|analog television standards]], have switched to, or are in process of switching to, newer [[Engineering:Digital television|digital television]] standards, with there being at least four different standards in use around the world. North America, parts of Central America, and {{wipe|South Korea}} are adopting or have adopted the [[ATSC standards|ATSC]] standards, while other countries, such as {{wipe|Japan}}, are adopting or have adopted other standards instead of ATSC. After nearly 70&nbsp;years, the majority of over-the-air NTSC transmissions in the United States ceased on June 12, 2009,<ref name=":0">[http://www.fcc.gov/digital-television Digital Television]. FCC.gov. Retrieved on May 11, 2014.</ref> and by August 31, 2011,<ref name="fcc.gov">[http://www.fcc.gov/guides/dtv-and-over-air-viewers-along-us-borders DTV and Over-the-Air Viewers Along U.S. Borders]. FCC.gov. Retrieved on May 11, 2014.</ref> in {{wipe|Canada}} and most other NTSC markets.<ref name="canadapalorntsc">[http://forum.videohelp.com/threads/131937-Canada-PAL-or-NTSC Canada... PAL or NTSC?]. VideoHelp Forum Retrieved on January 23, 2015.</ref> 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.<ref name="fcc.gov"/> 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 [[Engineering:High-definition television|higher-resolution television]], but [[Engineering:Standard-definition television|digital standard definition television]] continues to use the frame rate and number of lines of resolution established by the analog NTSC standard.

== Technical details ==

=== Resolution and refresh rate ===
NTSC color encoding is used with the [[CCIR System M|System M]] television signal, which consists of {{frac|30|1.001}}&nbsp;(approximately 29.97)&nbsp;[[Interlaced video|interlace]]d frames of [[Engineering:Video|video]] per [[Second|second]]. Each frame is composed of two fields, each consisting of 262.5&nbsp;scan lines, for a total of 525&nbsp;scan lines. The visible [[Raster scan|raster]] is made up of 486&nbsp;scan lines. The later digital standard, [[Rec. 601]], only uses 480 of these lines for visible raster. The remainder (the [[Engineering:Vertical blanking interval|vertical blanking interval]]) allow for vertical [[Synchronization|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 [[Engineering:Closed captioning|closed captioning]] and vertical interval [[Timecode|timecode]] (VITC). In the complete [[Raster scan|raster]] (disregarding half lines due to [[Interlaced video|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 [[Physics:Frequency|frequency]] of {{frac|60|1.001}}&nbsp;Hz (approximately 59.94&nbsp;Hz). For comparison, 625&nbsp;lines (576&nbsp;visible) systems, usually used with [[Engineering:PAL|PAL-B/G]] and [[Engineering:SECAM|SECAM]] color, and so have a higher vertical resolution, but a lower temporal resolution of 25&nbsp;frames or 50&nbsp;fields per second.

The NTSC field refresh frequency in the black-and-white system originally exactly matched the nominal 60&nbsp;Hz [[Physics:Utility frequency|frequency]] of [[Physics:Alternating current|alternating current]] power used in the United States. Matching the field [[Refresh rate|refresh rate]] to the power source avoided [[Intermodulation|intermodulation]] (also called ''beating''), which produces rolling bars on the screen. Synchronization of the refresh rate to the power incidentally helped [[Engineering:Kinescope|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. This, as mentioned, is how the NTSC field refresh frequency worked in the original black-and-white system; when ''color'' was added to the system, however, the refresh frequency was shifted slightly downward by 0.1%, to approximately 59.94&nbsp;Hz, to eliminate stationary dot patterns in the difference frequency between the sound and color carriers (as explained below in §{{spaces}}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&nbsp;lines was chosen as a consequence of the limitations of the vacuum-tube-based technologies of the day. In early TV systems, a master [[Engineering:Phase-locked loop|voltage-controlled oscillator]] was run at twice the horizontal line frequency, and this [[Engineering:Frequency divider|frequency was divided]] down by the number of lines used (in this case 525) to give the field frequency (60&nbsp;Hz in this case). This frequency was then compared with the 60&nbsp;Hz [[Physics:Utility frequency|power-line frequency]] and any discrepancy [[Engineering:Frequency-locked loop|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,{{clarify|date=May 2022}} 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 [[Physics:Vacuum tube|vacuum tube]] [[Engineering:Multivibrator|multivibrator]]s, 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 [[Engineering:Frequency drift|thermal drift]] with vacuum tube devices. The closest practical sequence to 500 that meets these criteria was {{math|3&times;5&times;5&times;7{{=}}525}}. (For the same reason, 625-line PAL-B/G and SECAM uses {{math|5&times;5&times;5&times;5}}, the old [[Engineering:405-line television system|British 405-line system]] used {{math|3&times;3&times;3&times;3&times;5}}, the French [[Engineering:819 line|819-line]] system used {{math|3&times;3&times;7&times;13}} etc.)

=== Colorimetry ===
[[File:NTSC 1953 RGB Colorcube.png|thumb|NTSC 1953 colorimetry color cube (color profile encoded, requires a compatible browser and monitor for accurate display).]]
The original 1953 color NTSC specification, still part of the United States Code of Federal Regulations, defined the [[Physics:Colorimetry|colorimetric]] values of the system as follows:<ref>47 CFR § 73.682 (20) (iv)</ref>
{| class="wikitable"
! rowspan="2" | [[Color space]]
! colspan="2" | White point
! colspan="1" | [[Earth:Correlated color temperature|CCT]]
! colspan="6" | [[Primary color]]s (CIE 1931)
|-
! x<sub>W</sub>
! y<sub>W</sub>
! K
! x<sub>R</sub>
! y<sub>R</sub>
! x<sub>G</sub>
! y<sub>G</sub>
! x<sub>B</sub>
! y<sub>B</sub>
|-
| align="“left"" | Original NTSC colorimetry (1953)
| 0.310
| 0.316
| 6774 <small>([[Physics:Standard illuminant#Illuminants B and C|Illuminant C]])</small>
| 0.67
| 0.33
| 0.21
| 0.71
| 0.14
| 0.08
|}
Early color television receivers, such as the RCA CT-100, were faithful to this specification (which was based on prevailing motion picture standards), having a larger gamut than most of today's monitors. Their low-efficiency phosphors (notably in the Red) were weak and long-persistent, leaving trails after moving objects. Starting in the late 1950s, picture tube phosphors would sacrifice saturation for increased brightness; this deviation from the standard at both the receiver and broadcaster was the source of considerable color variation.

==== SMPTE C ====
{{anchor|Color correction in studio monitors and home receivers}}
[[File:SMPTE-C RGB color cube.png|thumb|SMPTE C color cube (color profile encoded, requires a compatible browser and monitor for accurate display).]]
To ensure more uniform color reproduction, receivers started to incorporate color correction circuits that converted the received signal—encoded for the colorimetric values listed above—into signals encoded for the phosphors actually used within the monitor. Since such color correction can not be performed accurately on the nonlinear [[Physics:Gamma correction|gamma corrected]] signals transmitted, the adjustment can only be approximated, introducing both hue and [[Engineering:Luma (video)|luminance]] errors for highly saturated colors.

Similarly at the broadcaster stage, in 1968–69 the Conrac Corp., working with RCA, defined a set of controlled phosphors for use in broadcast color picture [[Engineering:Display device|video monitors]].<ref name="DeMarsh, Leroy 1098">DeMarsh, Leroy (1993): TV Display Phosphors/Primaries&nbsp;— Some History. SMPTE Journal, December 1993: 1095–1098. {{doi|10.5594/J01650}}</ref> This specification survives today as the '''SMPTE "C"''' phosphor specification:<!--
{| class="wikitable"
|+'''RGB color space parameters'''
|-
! rowspan="2" | [[Color space]]
! colspan="2" | White point
! colspan="6" | Primaries
|-
! x<sub>W</sub>
! y<sub>W</sub>
! x<sub>R</sub>
! y<sub>R</sub>
! x<sub>G</sub>
! y<sub>G</sub>
! x<sub>B</sub>
! y<sub>B</sub>
|-
| align="center" | SMPTE C
| 0.3127
| 0.3290
| 0.63
| 0.34
| 0.31
| 0.595
| 0.155
| 0.07
|}-->

{| class="wikitable"
! rowspan="2" | [[Color space]]
! colspan="2" | White point
! colspan="1" | [[Earth:Correlated color temperature|CCT]]
! colspan="6" | [[Primary color]]s (CIE 1931)
|-
! x<sub>W</sub>
! y<sub>W</sub>
! K
! x<sub>R</sub>
! y<sub>R</sub>
! x<sub>G</sub>
! y<sub>G</sub>
! x<sub>B</sub>
! y<sub>B</sub>
|-
| align="“left"" | SMPTE "C" colorimetry (1987)
| 0.3127
| 0.329
| 6500 ([[Physics:Standard illuminant|Ill<small>uminant</small>]] <small>[[Physics:Illuminant D65|D65]])</small>
| 0.63
| 0.34
| 0.31
| 0.595
| 0.155
| 0.070
|}
As with home receivers, it was further recommended<ref name="ITU470">International Telecommunication Union Recommendation ITU-R 470-6 (1970–1998): Conventional Television Systems, Annex 2.</ref> that studio monitors incorporate similar color correction circuits so that broadcasters would transmit pictures encoded for the original 1953 colorimetric values, in accordance with FCC standards.

In 1987, the Society of Motion Picture and Television Engineers (SMPTE) Committee on Television Technology, Working Group on Studio Monitor Colorimetry, adopted the SMPTE C (Conrac) phosphors for general use in Recommended Practice 145,<ref name="SMPTE_RP145">Society of Motion Picture and Television Engineers (1987–2004): Recommended Practice RP 145–2004. Color Monitor Colorimetry.</ref> prompting many manufacturers to modify their camera designs to directly encode for SMPTE "C" colorimetry without color correction,<ref name="SMPTE_EG27">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</ref> as approved in SMPTE standard 170M, "Composite Analog Video Signal&nbsp;– NTSC for Studio Applications" (1994). As a consequence, the [[ATSC standards|ATSC]] digital television standard states that for [[Engineering:480i|480i]] signals, SMPTE "C" colorimetry should be assumed unless colorimetric data is included in the transport stream.<ref>Advanced Television Systems Committee (2003): ATSC Direct-to-Home Satellite Broadcast Standard Doc. A/81, pp.18</ref>

Japanese NTSC never changed primaries and whitepoint to SMPTE "C", continuing to use the 1953 NTSC primaries and whitepoint.<ref name="ITU470"/> Both the [[Engineering:PAL|PAL]] and [[Engineering:SECAM|SECAM]] systems used the original 1953 NTSC colorimetry as well until 1970;<ref name="ITU470"/> unlike NTSC, however, the European Broadcasting Union (EBU) rejected color correction in receivers and studio monitors that year and instead explicitly called for all equipment to directly encode signals for the "EBU" colorimetric values,<ref name="EBU1975">European Broadcasting Union (1975) Tech. 3213-E.: E.B.U. Standard for Chromaticity Tolerances for Studio Monitors.</ref> further improving the color fidelity of those systems.

=== Color encoding ===
For backward compatibility with black-and-white television, NTSC uses a [[Engineering:Luma (video)|luminance]]-[[Engineering:Chrominance|chrominance]] encoding system invented in 1938 by [[Engineering:Georges Valensi|Georges Valensi]]. The ''three'' color picture signals are divided into Luminance (derived mathematically from the three separate color signals (Red, Green and Blue))<ref>{{cite web| url = http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/POYNTON1/ColorFAQ.html#RTFToC9| title = Poynton's Color FAQ by Charles Poynton|website=Homepages.inf.ed.ac.uk}}</ref> which takes the place of the original [[Engineering:Analog television|monochrome signal]] and Chrominance which carries ''only'' the color information. This process is applied to ''each'' color source by its own [[Colorplexer]], thereby allowing a compatible color source to be managed as if it were an ordinary monochrome source. This allows black-and-white receivers to display NTSC color signals by simply ignoring the chrominance signal. Some black-and-white TVs sold in the U.S. after the introduction of color broadcasting in 1953 were designed to filter chroma out, but the early B&W sets did not do this and [[Engineering:Chroma dots|chrominance]] could be seen as a 'dot pattern' in highly colored areas of the picture.

In NTSC, chrominance is encoded using two color signals known as I (in-phase) and Q (in quadrature) in a process called [[Quadrature amplitude modulation|QAM]]. The two signals each amplitude modulate 3.58&nbsp;MHz carriers which are 90&nbsp;degrees out of phase with each other and the result added together but with the [[Physics:Double-sideband suppressed-carrier transmission|carriers themselves being suppressed]]. The result can be viewed as a single sine wave with varying phase relative to a reference carrier and with varying amplitude. The varying phase represents the instantaneous ''color hue'' captured by a TV camera, and the amplitude represents the instantaneous ''color saturation''. This 3.58&nbsp;MHz [[Engineering:Subcarrier|subcarrier]] is then added to the Luminance to form the ''composite color signal'' which modulates the video signal [[Carrier wave|carrier]] just as in monochrome transmission.

For a color TV to recover hue information from the color subcarrier, it must have a zero-phase reference to replace the previously suppressed carrier. The NTSC signal includes a short sample of this reference signal, known as the [[Engineering:Colorburst|colorburst]], located on the ''back porch'' of each horizontal synchronization pulse. The color burst consists of a minimum of eight cycles of the unmodulated (fixed phase and amplitude) color subcarrier. The TV receiver has a ''local oscillator'', which is synchronized with these color bursts. Combining this reference phase signal derived from the color burst with the chrominance signal's amplitude and phase allows the recovery of the I and Q signals which when combined with the luminance information allows the reconstruction of a color image on the screen. Color TV has been said to really be color''ed'' TV because of the total separation of the brightness part of the picture from the color portion. In CRT televisions, the NTSC signal is turned into three color signals: red green and blue, each controlling that color electron gun. TV sets with digital circuitry use sampling techniques to process the signals but the result is the same. For both analog and digital sets processing an analog NTSC signal, the original three color signals are transmitted using three discrete signals (luminance, I and Q) and then recovered as three separate colors and combined as a color image.

When a transmitter broadcasts an NTSC signal, it amplitude-modulates a radio-frequency carrier with the NTSC signal just described, while it frequency-modulates a carrier 4.5&nbsp;MHz higher with the audio signal. If non-linear distortion happens to the broadcast signal, the 3.579545&nbsp;MHz color carrier may [[Physics:Beat (acoustics)|beat]] with the sound carrier to produce a dot pattern on the screen. To make the resulting pattern less noticeable, designers adjusted the original 15,750&nbsp;Hz scanline rate down by a factor of 1.001 (0.1%) to match the audio carrier frequency divided by the factor 286, resulting in a field rate of approximately 59.94&nbsp;Hz. This adjustment ensures that the difference between the sound carrier and the color subcarrier (the most problematic [[Intermodulation|intermodulation]] product of the two carriers) is an odd multiple of half the line rate, which is the necessary condition for the dots on successive lines to be opposite in phase, making them least noticeable.

The 59.94&nbsp;rate is derived from the following calculations. Designers chose to make the chrominance subcarrier frequency an ''n'' + 0.5 multiple of the line frequency to minimize interference between the luminance signal and the chrominance signal. (Another way this is often stated is that the color subcarrier frequency is an odd multiple of half the line frequency.) They then chose to make the audio subcarrier frequency an integer multiple of the line frequency to minimize visible (intermodulation) interference between the audio signal and the chrominance signal. The original black-and-white standard, with its 15,750&nbsp;Hz line frequency and 4.5&nbsp;MHz audio subcarrier, does not meet these requirements, so designers had to either raise the audio subcarrier frequency or lower the line frequency. Raising the audio subcarrier frequency would prevent existing (black and white) receivers from properly tuning in the audio signal. Lowering the line frequency is comparatively innocuous, because the horizontal and vertical synchronization information in the NTSC signal allows a receiver to tolerate a substantial amount of variation in the line frequency. So the engineers chose the line frequency to be changed for the color standard. In the black-and-white standard, the ratio of audio subcarrier frequency to line frequency is {{frac|4.5&nbsp;MHz|15,750&nbsp;Hz}}&nbsp;{{=}}&nbsp;285.71. In the color standard, this becomes rounded to the integer 286, which means the color standard's line rate is {{frac|4.5&nbsp;MHz|286}}&nbsp;&asymp;&nbsp;15,734&nbsp;Hz. Maintaining the same number of scan lines per field (and frame), the lower line rate must yield a lower field rate. Dividing {{frac|4500000|286}} lines per second by 262.5&nbsp;lines per field gives approximately 59.94&nbsp;fields per second.
<!--
There are two reasons why this is important. First, the chrominance signal was interpreted as part of the luminance by monochrome TV sets that were in use at the time of the introduction of color TV (which didn't have notch filters to remove the chrominance carrier), causing dots to appear on strongly contrasting edges (which are high-frequency video information.) The chosen line rate causes the dots to move, which makes them harder for the human eye to follow. The effect is still noticeable on close examination, however, and is referred to as [[Engineering:Dot crawl|dot crawl]]. A second benefit of the chosen field rate was realized much later: The phase difference of the interference pattern on successive lines makes it very easy to design a simple [[Comb filter|comb filter]] to separate chrominance and luminance information to a greater degree. -->

=== Transmission modulation method ===
[[File:Ntsc channel.svg|thumb|400px|right|Spectrum of a System M television channel with NTSC color]]

An NTSC [[Engineering:Television channel|television channel]] as transmitted occupies a total bandwidth of 6&nbsp;MHz. The actual video signal, which is [[Physics:Amplitude modulation|amplitude-modulated]], is transmitted between 500&nbsp;[[Hertz|kHz]] and 5.45&nbsp;MHz above the lower bound of the channel. The video [[Carrier wave|carrier]] is 1.25&nbsp;MHz above the lower bound of the channel. Like most AM signals, the video carrier generates two sidebands, one above the carrier and one below. The sidebands are each 4.2&nbsp;MHz wide. The entire upper sideband is transmitted, but only 1.25&nbsp;MHz of the lower sideband, known as a [[Physics:Single-sideband modulation|vestigial sideband]], is transmitted. The color subcarrier, as noted above, is 3.579545&nbsp;MHz above the video carrier, and is [[Quadrature amplitude modulation|quadrature-amplitude-modulated]] with a suppressed carrier. The audio signal is [[Physics:Frequency modulation|frequency-modulated]], like the audio signals broadcast by [[Engineering:FM broadcasting|FM radio]] [[Engineering:Radio broadcasting|stations]] in the 88–108&nbsp;MHz band, but with a 25&nbsp;kHz maximum [[Frequency deviation|frequency deviation]], as opposed to 75&nbsp;kHz as is used on the [[Engineering:FM broadcast band|FM band]], making analog television audio signals sound quieter than FM radio signals as received on a wideband receiver. The main audio carrier is 4.5&nbsp;MHz above the video carrier, making it 250&nbsp;kHz below the top of the channel. Sometimes a channel may contain an MTS signal, which offers more than one audio signal by adding one or two subcarriers on the audio signal, each synchronized to a multiple of the line frequency. This is normally the case when stereo audio and/or [[Engineering:Second audio program|second audio program]] signals are used. The same extensions are used in [[ATSC standards|ATSC]], where the ATSC digital carrier is broadcast at 0.31&nbsp;MHz above the lower bound of the channel.

"Setup" is a 54&nbsp;mV (7.5&nbsp;[[IRE (unit)|IRE]]) voltage offset between the "black" and "blanking" levels. It is unique to NTSC. CVBS stands for Color, Video, Blanking, and Sync.

The following table shows the values for the basic RGB colors, encoded in NTSC<ref>{{cite web|url=https://www.edn.com/wp-content/uploads/media-1050361-c0195-table1.gif |format=GIF|title=Color Bar Levels, Amplitues, and Phases|website=Edn.com|access-date=February 22, 2022}}</ref>
{| class="wikitable"
|+ Analog signal values for basic RGB colors, encoded in NTSC
|-
! Color
! [[Engineering:Luma (video)|Luminance]] level
([[IRE (unit)|IRE]])
! [[Engineering:Chrominance|Chrominance]] level
(IRE)
! Chrominance amplitude
(IRE)
! Phase
(º)
|-
! White
| 100.0
| 0.0
| 0.0
|–
|-
! Yellow
| 89.5
| 48.1 to 130.8
| 82.7
| 167.1
|-
! Cyan
| 72.3
| 13.9 to 130.8
| 116.9
| 283.5
|-
! Green
| 61.8
| 7.2 to 116.4
| 109.2
| 240.7
|-
! Magenta
| 45.7
| −8.9 to 100.3
| 109.2
| 60.7
|-
! Red
| 35.2
| −23.3 to 93.6
| 116.9
| 103.5
|-
! Blue
| 18.0
| −23.3 to 59.4
| 82.7
| 347.1
|-
! Black
| 7.5
| 0.0
| 0.0
|–
|}

=== Frame rate conversion ===

There is a large difference in [[Frame rate|frame rate]] between film, which runs at 24.0&nbsp;frames per second, and the NTSC standard, which runs at approximately 29.97 (10&nbsp;MHz×63/88/455/525)&nbsp;frames per second.
In regions that use 25-fps television and video standards, this difference can be overcome by [[576i#PAL speed-up|speed-up]].

For 30-fps standards, a process called "[[Engineering:Three-two pull down|3:2 pulldown]]" is used. One film frame is transmitted for three video fields (lasting {{frac|1|1|2}}&nbsp;video frames), and the next frame is transmitted for two video fields (lasting 1&nbsp;video frame). Two film frames are thus transmitted in five video fields, for an average of {{frac|2|1|2}}&nbsp;video fields per film frame. The average frame rate is thus 60 ÷ 2.5 = 24&nbsp;frames per second, so the average film speed is nominally exactly what it should be. (In reality, over the course of an hour of real time, 215,827.2&nbsp;video fields are displayed, representing 86,330.88&nbsp;frames of film, while in an hour of true 24-fps film projection, exactly 86,400&nbsp;frames are shown: thus, 29.97-fps NTSC transmission of 24-fps film runs at 99.92% of the film's normal speed.) Still-framing on playback can display a video frame with fields from two different film frames, so any difference between the frames will appear as a rapid back-and-forth flicker. There can also be noticeable jitter/"stutter" during slow camera pans ([[Engineering:Telecine#Telecine judder|telecine judder]]).

Film shot specifically for NTSC television is usually taken at 30 (instead of 24) frames per second to avoid 3:2 pulldown.<ref>{{cite journal |last1=Kennel |first1=Glenn |last2=Pytlak |first2=John |last3=Sehlin |first3=Richard |last4=Uhlig |first4=Ronald |title=Major Motion-Picture Production Standards |journal=SMPTE Journal |date=December 1988 |volume=97 |issue=12 |pages=985–990 |doi=10.5594/J02849 |url=https://ieeexplore.ieee.org/document/7258828 |access-date=12 March 2023 |url-access=subscription}}</ref>

To show 25-fps material (such as European [[Engineering:Television show|television series]] and some European movies) on NTSC equipment, every fifth frame is duplicated and then the resulting stream is interlaced.

Film shot for NTSC television at 24 frames per second has traditionally been accelerated by 1/24 (to about 104.17% of normal speed) for transmission in regions that use 25-fps television standards. This increase in picture speed has traditionally been accompanied by a similar increase in the pitch and tempo of the audio. More recently, frame-blending has been used to convert 24 FPS video to 25 FPS without altering its speed.

Film shot for television in regions that use 25-fps television standards can be handled in either of two ways:

* The film can be shot at 24 frames per second. In this case, when transmitted in its native region, the film may be accelerated to 25 fps according to the analog technique described above, or kept at 24 fps by the digital technique described above. When the same film is transmitted in regions that use a nominal 30-fps television standard, there is no noticeable change in speed, tempo, and pitch.
* The film can be shot at 25 frames per second. In this case, when transmitted in its native region, the film is shown at its normal speed, with no alteration of the accompanying soundtrack. When the same film is shown in regions that use a 30-fps nominal television standard, every fifth frame is duplicated, and there is still no noticeable change in speed, tempo, and pitch.

Because both film speeds have been used in 25-fps regions, viewers can face confusion about the true speed of video and audio, and the pitch of voices, sound effects, and musical performances, in television films from those regions. For example, they may wonder whether the Jeremy Brett series of Sherlock Holmes television films, made in the 1980s and early 1990s, was shot at 24&nbsp;fps and then transmitted at an artificially fast speed in 25-fps regions, or whether it was shot at 25 fps natively and then slowed to 24 fps for NTSC exhibition.

These discrepancies exist not only in television broadcasts over the air and through cable, but also in the home-video market, on both tape and disc, including [[LaserDisc|laser disc]] and [[Engineering:DVD|DVD]].

In digital television and video, which are replacing their analog predecessors, single standards that can accommodate a wider range of frame rates still show the limits of analog regional standards. The initial version of the [[ATSC standards|ATSC]] standard, for example, allowed frame rates of 23.976, 24, 29.97, 30, 59.94, 60, 119.88 and 120 frames per second, but not 25 and 50. Modern ATSC allows 25 and 50 FPS.

=== Modulation for analog satellite transmission ===
Because satellite power is severely limited, analog video transmission through satellites differs from terrestrial TV transmission. [[Physics:Amplitude modulation|AM]] is a linear modulation method, so a given demodulated [[Physics:Signal-to-noise ratio|signal-to-noise ratio]] (SNR) requires an equally high received RF SNR. The SNR of studio quality video is over 50&nbsp;dB, so AM would require prohibitively high powers and/or large antennas.

Wideband [[Physics:Frequency modulation|FM]] is used instead to trade RF bandwidth for reduced power. Increasing the channel bandwidth from 6 to 36&nbsp;MHz allows a RF SNR of only 10&nbsp;dB or less. The wider noise bandwidth reduces this 40&nbsp;dB power saving by 36&nbsp;MHz / 6&nbsp;MHz = 8&nbsp;dB for a substantial net reduction of 32&nbsp;dB.

Sound is on an FM subcarrier as in terrestrial transmission, but frequencies above 4.5&nbsp;MHz are used to reduce aural/visual interference. 6.8, 5.8 and 6.2&nbsp;MHz are commonly used. Stereo can be multiplex, discrete, or matrix and unrelated audio and data signals may be placed on additional subcarriers.

A triangular 60&nbsp;Hz energy dispersal waveform is added to the composite baseband signal (video plus audio and data subcarriers) before modulation. This limits the satellite downlink [[Physics:Spectral density|power spectral density]] in case the video signal is lost. Otherwise the satellite might transmit all of its power on a single frequency, interfering with terrestrial microwave links in the same frequency band.

In half transponder mode, the frequency deviation of the composite baseband signal is reduced to 18&nbsp;MHz to allow another signal in the other half of the 36&nbsp;MHz transponder. This reduces the FM benefit somewhat, and the recovered SNRs are further reduced because the combined signal power must be "backed off" to avoid intermodulation distortion in the satellite transponder. A single FM signal is constant amplitude, so it can saturate a transponder without distortion.

=== Field order ===
An NTSC ''frame'' consists of two ''fields,'' F1 (field one) and F2 (field two). The [[Field dominance|field dominance]] depends on a combination of factors, including decisions by various equipment manufacturers as well as historical conventions. As a result, most professional equipment has the option to switch between a dominant upper or dominant lower field. It is not advisable to use the terms ''even'' or ''odd'' when speaking of fields, due to substantial ambiguity. For instance if the line numbering for a particular system starts at zero, while another system starts its line numbering at one. As such the same field could be even or odd.<ref name=":0" /><ref>{{Cite web |title=Programmer's Guide to Video Systems - Lurker's Guide - lurkertech.com |url=https://lurkertech.com/lg/video-systems/#f1f2 |access-date=2023-01-25 |website=lurkertech.com}}</ref>

While an analog television set does not care about field dominance per se, field dominance is important when editing NTSC video. Incorrect interpretation of field order can cause a shuddering effect as moving objects jump forward and behind on each successive field.

This is of particular importance when interlaced NTSC is transcoded to a format with a different field dominance and vice versa. Field order is also important when transcoding progressive video to interlaced NTSC, as any place there is a cut between two scenes in the progressive video, there could be a flash field in the interlaced video if the field dominance is incorrect. The film telecine process where a [[Engineering:Three-two pull down|three-two pull down]] is utilized to convert 24 frames to 30, will also provide unacceptable results if the field order is incorrect.

Because each field is temporally unique for material captured with an interlaced camera, converting interlaced to a digital progressive-frame medium is difficult, as each progressive frame will have artifacts of motion on every alternating line. This can be observed in PC-based video-playing utilities and is frequently solved simply by transcoding the video at half resolution and only using one of the two available fields.

== Variants ==

=== NTSC-M ===
Unlike PAL and SECAM, with its many varied underlying [[Engineering:Broadcast television systems|broadcast television systems]] in use throughout the world, NTSC color encoding is almost invariably used with [[CCIR System M|broadcast system '''M''']], giving NTSC-M.

=== NTSC-N and NTSC-50 ===
NTSC-N was originally proposed in the 1960s to the [[Organization:ITU-R#CCIR|CCIR]] as a 50&nbsp;Hz broadcast method for [[CCIR System N|System N]] countries Paraguay, Uruguay and Argentina before they chose PAL-N. In the mid 1980s, it was effectively reintroduced as NTSC-50, a pseudo-system combining 625-line video with 3.58&nbsp;MHz NTSC color.  For example, an [[Engineering:Atari ST|Atari ST]] running PAL software on their NTSC color display used this system as the monitor could not decode PAL color. Most analog NTSC television sets and monitors with a V-Hold knob can display this system after adjusting the vertical hold.<ref>{{cite web |last=VWestlife's Camcorder Tests & More |date=January 6, 2010 |title=Recording PAL and 625-line 50 Hz NTSC video on a U.S. VCR |url=https://www.youtube.com/watch?v=REsrXKGuPpg |via=YouTube}}</ref>

=== NTSC-J ===
Only {{wipe|Japan}}'s variant "[[Engineering:NTSC-J|NTSC-J]]" is slightly different: in Japan, black level and blanking level of the signal are identical (at 0&nbsp;[[IRE (unit)|IRE]]), as they are in PAL, while in American NTSC, black level is slightly higher (7.5&nbsp;[[IRE (unit)|IRE]]) than blanking level. Since the difference is quite small, a slight turn of the brightness knob is all that is required to correctly show the "other" variant of NTSC on any set as it is supposed to be; most watchers might not even notice the difference in the first place. The channel encoding on NTSC-J differs slightly from NTSC-M. In particular, the Japanese VHF band runs from channels 1–12 (located on frequencies directly above the 76–90&nbsp;MHz Japanese [[Engineering:FM broadcasting|FM radio]] band) while the North American VHF TV band uses channels 2–13 (54–72&nbsp;MHz, 76–88&nbsp;MHz and 174–216&nbsp;MHz) with 88–108&nbsp;MHz allocated to FM radio broadcasting. Japan's UHF TV channels are therefore numbered from 13 up and not 14 up, but otherwise uses the same UHF broadcasting frequencies as those in North America.

=== NTSC 4.43 ===
NTSC 4.43 is a pseudo-system that transmits a NTSC color subcarrier of 4.43&nbsp;MHz instead of 3.58&nbsp;MHz<ref>{{Cite book|url=https://books.google.com/books?id=rsEwE2X3cFAC&dq=NTSC+4.43&pg=PA580|title = Digital Video and HD: Algorithms and Interfaces|isbn = 9781558607927|last1 = Poynton|first1 = Charles|year = 2003| publisher=Morgan Kaufmann }}</ref> The resulting output is only viewable by TVs that support the resulting pseudo-system (such as most PAL TVs).<ref>{{cite web
 |url=https://www.weethet.nl/english/video_formats.php  |title=WeetHet - Video - Overview of available formats |access-date=September 21, 2022
|quote=Most modern TV-sets accept the so called pseudo formats (Pseudo PAL and Pseudo NTSC) ...}}</ref> Using a native NTSC TV to decode the signal yields no color, while using an incompatible PAL TV to decode the system yields erratic colors (observed to be lacking red and flickering randomly). The format was used by the {{wipe|United States Air Force}} TV based in Germany during the [[History:Cold War|Cold War]].<ref>{{cite web |title=Variants of NTSC standard |url=https://www.hisour.com/variants-of-ntsc-standard-25937/ |date=March 25, 2018}}</ref> It was also found as an optional output on some [[LaserDisc]] players and some game consoles sold in markets where the PAL system is used.

The NTSC 4.43 system, while not a broadcast format, appears most often as a playback function of PAL cassette format VCRs, beginning with the Sony 3/4" U-Matic format and then following onto Betamax and VHS format machines, commonly advertised as "NTSC playback on PAL TV". As Hollywood has the claim of providing the most cassette software (movies and television series) for VCRs for the world's viewers, and as not ''all'' cassette releases were made available in PAL formats, a means of playing NTSC format cassettes was highly desired.

Multi-standard video monitors were already in use in Europe to accommodate broadcast sources in PAL, SECAM, and NTSC video formats. The [[Heterodyne#Heterodyning in analog videotape recording|heterodyne]] color-under process of U-Matic, Betamax & VHS lent itself to minor modification of VCR players to accommodate NTSC format cassettes. The color-under format of VHS uses a 629&nbsp;kHz subcarrier while U-Matic & Betamax use a 688&nbsp;kHz subcarrier to carry an ''amplitude modulated'' chroma signal for both NTSC and PAL formats. Since the VCR was ready to play the color portion of the NTSC recording using PAL color mode, the PAL scanner and capstan speeds had to be adjusted from PAL's 50&nbsp;Hz field rate to NTSC's 59.94&nbsp;Hz field rate, and faster linear tape speed.

The changes to the PAL VCR are minor thanks to the existing VCR recording formats. The output of the VCR when playing an NTSC cassette in NTSC 4.43 mode is 525&nbsp;lines/29.97&nbsp;frames per second with PAL compatible heterodyned color. The multi-standard receiver is already set to support the NTSC H & V frequencies; it just needs to do so while receiving PAL color.

The existence of those multi-standard receivers was probably part of the drive for region coding of DVDs. As the color signals are component on disc for all display formats, almost no changes would be required for PAL DVD players to play NTSC (525/29.97) discs as long as the display was frame-rate compatible.

=== OSKM (USSR-NTSC) ===
In January 1960, (7 years prior to adoption of the modified SECAM version) the experimental TV studio in Moscow started broadcasting using the OSKM system. OSKM was the version of NTSC adapted to European D/K 625/50 standard. The OSKM abbreviation means "Simultaneous system with quadrature modulation" (In Russian: Одновременная Система с Квадратурной Модуляцией). It used the color coding scheme that was later used in PAL (U and V instead of I and Q).

The color subcarrier frequency was 4.4296875&nbsp;MHz and the bandwidth of U and V signals was near 1.5&nbsp;MHz.<ref>{{Cite book|url=http://ca.cryptocom.ru/tmpfiles/mrb_0469.djvu|title = Amateur Colour TV Receiver TSVET-2|last1 = Sokolov|first1 = Georgii|last2 = Sudravskii|first2 = Dmitrii|year = 1963}}</ref> Only circa 4000 TV sets of 4 models (Raduga,<ref>{{cite web |title=Raduga OSKM Color TV (1962) |url=http://rw6ase.narod.ru/00/twc/raduga_tw62.html |date=September 6, 2022}}</ref> Temp-22, Izumrud-201 and Izumrud-203<ref>{{cite web |title=Izumrud-203 OSKM Color TV (1959) |url=http://rw6ase.narod.ru/00/twc/izumrud203.html |date=September 6, 2022}}</ref>) were produced for studying the real quality of TV reception. These TV's were not commercially available, despite being included in the goods catalog for trade network of the USSR.

The broadcasting with this system lasted about 3 years and was ceased well before SECAM transmissions started in the USSR. None of the current multi-standard TV receivers can support this TV system.

=== NTSC-film ===
{{main|24p}}
Film content commonly shot at 24 frames/s can be converted to 30 frames/s through the [[Engineering:Telecine|telecine]] process to duplicate frames as needed.
:<math> \frac{23.976}{29.97} = \frac{4}{5}</math>

Mathematically for NTSC this is relatively simple as it is only needed to duplicate every fourth frame. Various techniques are employed. NTSC with an actual frame rate of {{frac|24|1.001}}&nbsp; (approximately 23.976)&nbsp;frames/s is often defined as NTSC-film. A process known as pullup, also known as pulldown, generates the duplicated frames upon playback. This method is common for H.262/MPEG-2 Part 2 digital video so the original content is preserved and played back on equipment that can display it or can be converted for equipment that cannot.


== Comparative quality ==
[[File:SMPTE Color Bars.svg|thumb|right|300px|The SMPTE color bars, an example of a test pattern ]]

For NTSC, and to a lesser extent, PAL, reception problems can degrade the color accuracy of the picture where ghosting can dynamically change the phase of the color burst with picture content, thus altering the color balance of the signal.  The only receiver compensation is in the professional TV receiver ghost canceling circuits used by cable companies.  The vacuum-tube electronics used in televisions through the 1960s led to various technical problems. Among other things, the color burst phase would often drift.  In addition, the TV studios did not always transmit properly, leading to hue changes when channels were changed, which is why NTSC televisions were equipped with a tint control. PAL and SECAM televisions had less of a need for one.  SECAM in particular was very robust, but PAL, while excellent in maintaining skin tones which viewers are particularly sensitive to, nevertheless would distort other colors in the face of phase errors.  With phase errors, only "Deluxe PAL" receivers would get rid of "Hanover bars" distortion.  Hue controls are still found on NTSC TVs, but color drifting generally ceased to be a problem for more modern circuitry by the 1970s. When compared to PAL, in particular, NTSC color accuracy and consistency were sometimes considered inferior, leading to video professionals and television engineers jokingly referring to NTSC as ''Never The Same Color'', ''Never Twice the Same Color'', or ''No True Skin Colors'',<ref>Jain, Anal K., ''Fundamentals of Digital Image Processing'', Upper Saddle River, NJ: Prentice Hall, 1989, p. 82.</ref> while for the more expensive PAL system it was necessary to ''Pay for Additional Luxury''.

PAL has also been referred to as ''Peace At Last'', ''Perfection At Last'' or ''Pictures Always Lovely'' in the color war. This mostly applied to vacuum tube-based TVs, however, and later-model solid state sets using Vertical Interval Reference signals have less of a difference in quality between NTSC and PAL. This color phase, "tint", or "hue" control allows for anyone skilled in the art to easily calibrate a monitor with [[Engineering:SMPTE color bars|SMPTE color bars]], even with a set that has drifted in its color representation, allowing the proper colors to be displayed.  Older PAL television sets did not come with a user accessible "hue" control (it was set at the factory), which contributed to its reputation for reproducible colors.

The use of NTSC coded color in [[S-Video]] systems, as well as the use of closed-circuit composite NTSC, both eliminate the phase distortions because there is no reception ghosting in a closed-circuit system to smear the color burst.  For VHS videotape on the horizontal axis and frame rate of the three color systems when used with this scheme, the use of S-Video gives the higher resolution picture quality on monitors and TVs without a high-quality motion-compensated comb filtering section.  (The NTSC resolution on the vertical axis is lower than the European standards, 525&nbsp;lines against 625.) However, it uses too much bandwidth for over-the-air transmission. The [[Engineering:Atari 8-bit family|Atari 800]] and [[Engineering:Commodore 64|Commodore 64]] home computers generated S-video, but only when used with specially designed monitors as no TV at the time supported the separate chroma and luma on standard [[Engineering:RCA connector|RCA jacks]]. In 1987, a standardized four-pin [[Engineering:Mini-DIN connector|mini-DIN]] socket was introduced for S-video input with the introduction of S-VHS players, which were the first device produced to use the four-pin plugs. However, S-VHS never became very popular. Video game consoles in the 1990s began offering S-video output as well.

The mismatch between NTSC's 30&nbsp;frames per second and film's 24&nbsp;frames is overcome by a process that capitalizes on the ''field'' rate of the interlaced NTSC signal, thus avoiding the film playback speedup used for 576i systems at 25&nbsp;frames per second (which causes the accompanying audio to increase in pitch slightly, sometimes rectified with the use of a [[Pitch shift|pitch shift]]er) at the price of some [[Engineering:Telecine#Telecine judder|jerkiness in the video]]. See Frame rate conversion above.

== Vertical interval reference ==
The standard NTSC video image contains some lines (lines 1–21 of each field) that are not visible (this is known as the [[Engineering:Vertical blanking interval|Vertical Blanking Interval]], or VBI); all are beyond the edge of the viewable image, but only lines 1–9 are used for the vertical-sync and equalizing pulses. The remaining lines were deliberately blanked in the original NTSC specification to provide time for the electron beam in CRT screens to return to the top of the display.

VIR (or Vertical interval reference), widely adopted in the 1980s, attempts to correct some of the color problems with NTSC video by adding studio-inserted reference data for luminance and chrominance levels on line 19.<ref>{{cite web |url=http://sipi.usc.edu/~weber/ee459/datasheets/LM1881.pdf |archive-url=https://web.archive.org/web/20060313071659/http://ee.usc.edu/library/ee459/datasheets/LM1881.pdf |archive-date=March 13, 2006 |title=LM1881 Video Sync Separator |date=March 13, 2006}}</ref> Suitably equipped television sets could then employ these data in order to adjust the display to a closer match of the original studio image. The actual VIR signal contains three sections, the first having 70 percent luminance and the same chrominance as the [[Engineering:Colorburst|color burst]] signal, and the other two having 50 percent and 7.5 percent luminance respectively.<ref>[http://danalee.ca/ttt/waveform_monitors_and_vectorscopes.htm Waveform Mons & Vectorscopes]. Danalee.ca. Retrieved on May 11, 2014.</ref>

A less-used successor to VIR, [[Engineering:Ghost-canceling reference|GCR]], also added ghost (multipath interference) removal capabilities.

The remaining [[Engineering:Vertical blanking interval|vertical blanking interval]] lines are typically used for [[Physics:Datacasting|datacasting]] or ancillary data such as video editing timestamps ([[Engineering:Vertical interval timecode|vertical interval timecode]]s or SMPTE timecodes on lines 12–14<ref>[http://www.philrees.co.uk/articles/timecode.htm SMPTE EBU timecode by Phil Rees]. Philrees.co.uk. Retrieved on May 11, 2014.</ref><ref>[http://poynton.com/notes/video/Timecode/ Technical Introduction to Timecode] {{webarchive |url=https://web.archive.org/web/20070710133402/http://www.poynton.com/notes/video/Timecode/ |date=July 10, 2007}}. Poynton.com. Retrieved on May 11, 2014.</ref>), [[Engineering:Video-signal generator|test data]] on lines 17–18, a network source code on line 20 and [[Engineering:Closed captioning|closed captioning]], [[Engineering:Extended Data Services|XDS]], and [[Engineering:V-chip|V-chip]] data on [[Engineering:EIA-608|line 21]]. Early teletext applications also used vertical blanking interval lines 14–18 and 20, but teletext over NTSC was never widely adopted by viewers.<ref>[https://www.experimentaltvcenter.org/vhp/tools   The History Project]. Experimentaltvcenter.org. Retrieved on May 11, 2014.</ref>

Many stations transmit TV Guide On Screen ([[Engineering:Guide Plus|TVGOS]]) data for an electronic program guide on VBI lines. The primary station in a market will broadcast 4&nbsp;lines of data, and backup stations will broadcast 1&nbsp;line. In most markets the PBS station is the primary host. TVGOS data can occupy any line from 10–25, but in practice its limited to 11–18, 20 and line 22. Line 22 is only used for 2 broadcast, [[Company:DirecTV|DirecTV]] and CFPL-TV.

TiVo data is also transmitted on some commercials and program advertisements so that customers can autorecord the program being advertised, and is also used in weekly half-hour [[Finance:Infomercial|paid programs]] on Ion Television and the Discovery Channel which highlight TiVo promotions and advertisers.

== Countries and territories that are using or once used NTSC ==
<!-- This is information that is truly a list in nature.  Converting it to prose would obfuscate it and make it harder to read, use, edit and update.  Please do not tag this genuine list for conversion to "prose" -->

Below are countries and territories that currently use or once used the NTSC system. Many of these have switched or are currently switching from NTSC to digital television standards such as [[ATSC standards|ATSC]] (United States, Canada, Mexico, Suriname, Jamaica, South Korea), [[Company:ISDB|ISDB]] (Japan, Philippines and part of South America), [[DVB-T]] (Taiwan, Panama, Colombia, Myanmar, and Trinidad and Tobago) or [[Engineering:Digital Terrestrial Multimedia Broadcast|DTMB]] (Cuba).

{{div col|colwidth=40em}}
* {{flag|American Samoa}}<ref name="HegartyPhelan1998">{{cite book |last1=Hegarty |first1=Michael |last2=Phelan |first2=Anne |last3=Kilbride |first3=Lisa |title=Classrooms for Distance Teaching and Learning: A Blueprint |url=https://books.google.com/books?id=5YjHecPlPS8C&pg=PA260 |publisher=Leuven University Press |date=January 1, 1998 |pages=260– |isbn=978-90-6186-867-5}}</ref>
* {{flag|Anguilla}}<ref name="HegartyPhelan1998"/>
* {{flag|Antigua and Barbuda}}<ref name="HegartyPhelan1998"/>
* {{flag|Aruba}}<ref name="HegartyPhelan1998"/>
* {{flag|Bahamas}}<ref name="HegartyPhelan1998"/>
* {{flag|Barbados}}<ref name="HegartyPhelan1998"/>
* {{flag|Belize}}<ref name="HegartyPhelan1998"/>
* {{flag|Bermuda}}<ref name="HegartyPhelan1998"/> (Over-the-air NTSC broadcasts (Channel 9) have been terminated as of March 2016, local broadcast stations have now switched to digital channels 20.1 and 20.2.)<ref>{{cite web |url=http://bernews.com/2016/03/dd-bermuda-broadcasting-moving-digital-tv-output/ |title=BBC's All-Digital TV Output Plans 'On Course' |date=March 9, 2016}}</ref>
* {{flag|Bolivia}}<ref name="HegartyPhelan1998"/>
* {{flag|Bonaire}}<ref name="HegartyPhelan1998"/>
* {{flag|British Virgin Islands}}<ref name="HegartyPhelan1998"/>
* {{flag|Canada}}<ref name="HegartyPhelan1998"/> (Over-the-air NTSC broadcasting in major cities ceased August 2011 as a result of legislative fiat, to be replaced with ATSC. Some one-station markets or markets served only by full-power repeaters remain analog.<ref>Canadian Radio-television and Telecommunications Commission (CRTC) [http://www.crtc.gc.ca/eng/NEWS/RELEASES/2007/r070517.htm Press release May 2007] {{webarchive |url=https://web.archive.org/web/20070519082346/http://www.crtc.gc.ca/eng/NEWS/RELEASES/2007/r070517.htm |date=May 19, 2007}}</ref>)
* {{flag|Caribbean Netherlands}}<ref name="HegartyPhelan1998"/>
* {{flag|Cayman Islands}}<ref name="HegartyPhelan1998"/>
* {{flag|Chile}}<ref name="HegartyPhelan1998"/> (Analog shutoff scheduled to 2024,<ref>{{cite web |url=https://www.subtel.gob.cl/cntv-y-subtel-culminan-primera-etapa-de-entrega-de-concesiones-de-television-digital-terrestre/ |title=CNTV y SUBTEL culminan primera etapa de entrega de concesiones de Televisión Digital Terrestre |date=June 27, 2019 |access-date=February 8, 2020 |archive-url=https://web.archive.org/web/20190928160231/https://www.subtel.gob.cl/cntv-y-subtel-culminan-primera-etapa-de-entrega-de-concesiones-de-television-digital-terrestre/ |archive-date=September 28, 2019 |url-status=live}}</ref> simulcasting in [[Engineering:ISDB-T International|ISDB-Tb]].)
* {{flag|Colombia}}<ref name="HegartyPhelan1998"/> (Analog shutoff scheduled to 2022, simulcasting [[DVB-T]].)
* {{flag|Costa Rica}}<ref name="HegartyPhelan1998"/> (NTSC broadcast to be abandoned by December 2018, simulcasting [[Engineering:ISDB-T International|ISDB-Tb]].)
* {{flag|Cuba}}<ref name="HegartyPhelan1998"/>
* {{flag|Curaçao}}<ref name="HegartyPhelan1998"/>
* {{flag|Dominica}}<ref name="HegartyPhelan1998"/>
* {{flag|Dominican Republic}}<ref name="HegartyPhelan1998"/> (Over-the-air NTSC broadcasting scheduled to be abandoned by 2021, simulcast in ATSC.<ref>{{cite web |url=https://www.indotel.gob.do//telecomunicaciones/televisión-digital-en-rd/ |title=Televisión Digital en RD |last=Indotel |website=Indotel.gob.do}}</ref>)
* {{flag|Ecuador}}<ref name="HegartyPhelan1998"/>
* {{flag|El Salvador}} (Over-the-air NTSC broadcasting scheduled to be abandoned by January 1, 2020, simulcast in [[Engineering:ISDB-T International|ISDB-Tb]].)
* {{flag|Grenada}}<ref name="HegartyPhelan1998"/>
* {{flag|Guam}}<ref name="HegartyPhelan1998"/>
* {{flag|Guatemala}}<ref name="HegartyPhelan1998"/>
* {{flag|Guyana}}<ref name="HegartyPhelan1998"/>
* {{flag|Haiti}}<ref name="HegartyPhelan1998"/>
* {{flag|Honduras}}<ref name="HegartyPhelan1998"/> (Over-the-air NTSC broadcasting scheduled to be abandoned by December 2020, simulcast in [[Engineering:ISDB-T International|ISDB-Tb]].)
* {{flag|Jamaica}}<ref name="HegartyPhelan1998"/> (Will convert to ATSC 3.0 instead of 1.0. The conversion will begin in 2022 and is expected to be completed by 2023.) <ref>{{cite news |title=Digital Television Switchover in Jamaica set to begin in 2022 |url=https://jamaica-gleaner.com/article/news/20211207/digital-television-switchover-jamaica-set-begin-2022 |work=The Gleaner |publisher=Gleaner Company |date=December 7, 2021 |access-date=January 8, 2021 }}</ref>
* {{flag|Japan}}<ref name="HegartyPhelan1998"/> (fully switched to [[Company:ISDB|ISDB]] in 2012, after the 2011 Tōhoku earthquake and tsunami delayed the planned 2011 rollout in three prefectures)
* {{flag|Marshall Islands}}<ref name="HegartyPhelan1998"/> (in Compact of Free Association with US; US aid funded NTSC adoption)
* {{flagcountry|Mexico}} plans to transition from NTSC announced on July 2, 2004,<ref name=ATSC_Mexico_2004>{{cite news |last=Hester |first=Lisa |title=Mexico To Adopt The ATSC DTV Standard |url=http://www.atsc.org/cms/index.php/communications/press-releases/128-mexico-to-adopt-the-atsc-dtv-standard |access-date=June 4, 2013 |newspaper=Advanced Television Systems Committee |date=July 6, 2004 |quote=On July 2 the Government of Mexico formally adopted the ATSC Digital Television (DTV) Standard for digital terrestrial television broadcasting. |url-status=dead |archive-url=https://web.archive.org/web/20140606212323/http://www.atsc.org/cms/index.php/communications/press-releases/128-mexico-to-adopt-the-atsc-dtv-standard |archive-date=June 6, 2014}}</ref> started conversion in 2013<ref name=Dibble_2013>{{cite news |last=Dibble |first=Sandra |title=New turn for Tijuana's transition to digital broadcasting |url=http://www.utsandiego.com/news/2013/may/30/new-turn-for-tijuanas-transition-to-digital-broac/ |access-date=June 4, 2013 |newspaper=San Diego Union-Tribune |date=May 30, 2013 |url-status=live |archive-url=https://web.archive.org/web/20130906225915/http://www.utsandiego.com/news/2013/may/30/new-turn-for-tijuanas-transition-to-digital-broac/ |archive-date=September 6, 2013 }}</ref> full transition was scheduled for December 31, 2015,<ref name="dgm 1">{{cite web |url=http://dof.gob.mx/nota_detalle.php?codigo=5157568&fecha=02/09/2010 |title=DOF – Diario Oficial de la Federación |website=dof.gob.mx |access-date=March 16, 2018 |url-status=live |archive-url=https://web.archive.org/web/20180121000019/http://dof.gob.mx/nota_detalle.php?codigo=5157568&fecha=02%2F09%2F2010 |archive-date=January 21, 2018 }}</ref> but due to technical and economic issues for some transmitters, the full transition was extended to be completed on December 31, 2016.
* {{flag|Micronesia}}<ref name="HegartyPhelan1998"/> (in Compact of Free Association with US, transitioning to [[DVB-T]])
* {{flag|Midway Atoll}} (a US military base)
* {{flag|Montserrat}}<ref name="HegartyPhelan1998"/>
* {{flag|Myanmar}}
* {{flag|Nicaragua}}<ref name="HegartyPhelan1998"/>
* {{flag|Northern Mariana Islands}}
* {{flag|Palau}}<ref name="HegartyPhelan1998"/> (in Compact of Free Association with US; adopted NTSC before independence)
* {{flag|Panama}}<ref name="HegartyPhelan1998"/> (NTSC broadcasts to be abandoned by 2020, simulcasting [[DVB-T]]. NTSC broadcasts to be abandoned in areas with more than 90% of DVB-T reception.)
* {{flag|Peru}}<ref name="HegartyPhelan1998"/> (NTSC broadcast to be abandoned by December 31, 2017, simulcasting [[Engineering:ISDB-T International|ISDB-Tb]].)<ref name="Cianci2012">{{cite book |author=Philip J. Cianci |title=High Definition Television: The Creation, Development and Implementation of HDTV Technology |url=https://books.google.com/books?id=0mbsfr38GTgC&pg=PA302 |date=January 9, 2012 |publisher=McFarland |pages=302– |isbn=978-0-7864-8797-4}}</ref>
* {{flag|Philippines}}<ref name="HegartyPhelan1998"/> (NTSC broadcast was intended to be abandoned at the end of 2015; however, in later 2014, it was postponed to 2019,<ref>{{cite web |url=http://nextvasia.com/dtt/philippines-to-start-digital-tv-shift-in-2019/ |title=Philippines to start digital TV shift in 2019 |access-date=October 27, 2014 |publisher=NexTV Asia-Pacific |url-status=dead |archive-url=https://web.archive.org/web/20150209183335/http://nextvasia.com/dtt/philippines-to-start-digital-tv-shift-in-2019/ |archive-date=February 9, 2015}}</ref> and later extended to 2023.<ref name="ntcph">{{cite web |url=http://www.gmanetwork.com/news/story/599484/money/companies/gov-t-wants-analog-tv-switched-off-by-2023 |title=Gov't wants analog TV switched off by 2023 |last=Cabuenas |first=Jon Viktor D. |publisher=GMA News Online |date=February 14, 2017 |access-date=December 6, 2018}}</ref><ref name="hardwareboom">{{cite web |last1=Dela Paz |first1=Chrisee |title=Hardware boom comes with PH shift to digital TV |url=https://www.rappler.com/business/161438-dict-philippines-digital-tv-shift |website=Rappler |access-date=January 21, 2019 |date=February 14, 2017}}</ref><ref name="broadcasterscommit">{{cite news |last1=Mariano |first1=Keith Richard D. |title=Broadcasters commit to digital TV switch by 2023 |url=http://bworldonline.com/content.php?section=Corporate&title=broadcasters-commit-to-digital-tv-switch-by-2023&id=140700 |newspaper=BusinessWorld |access-date=January 21, 2019 |date=February 16, 2017 |archive-date=February 24, 2021 |archive-url=https://web.archive.org/web/20210224133317/http://bworldonline.com/content.php?section=Corporate&title=broadcasters-commit-to-digital-tv-switch-by-2023&id=140700 |url-status=dead }}</ref><ref name="govtoncourse">{{cite news |last1=Esmael |first1=Maria Lisbet K. |title=Govt on course to hit 2023 full digital TV transition |url=https://www.manilatimes.net/govt-on-course-to-hit-2023-full-digital-tv-transition/449040/ |newspaper=The Manila Times |access-date=January 21, 2019 |date=October 7, 2018}}</ref><ref name="digitaltvshift">{{cite news |last1=Mercurio |first1=Richmond |title=Digital TV shift by 2023 pushing through — DICT |url=https://www.philstar.com/business/2018/10/04/1856959/digital-tv-shift-2023-pushing-through-dict |newspaper=The Philippine Star |access-date=January 21, 2019 |date=October 4, 2018}}</ref> All analog broadcasts are expected to be shut off by the end of 2024 or by 2026.<ref>{{Cite web |last=Rita |first=Joviland |date=March 30, 2022 |title=Switching off analog TV by 2023 should continue —Andanar |url=https://www.gmanetwork.com/news/topstories/nation/826831/switching-off-analog-tv-by-2023-should-continue-andanar/story/ |access-date=September 23, 2022 |work=GMA News Online}}</ref><ref name=":1">{{Cite web |last=LOCUS |first=SUNDY |date=2024-01-15 |title=NTC: Preparations underway for analog TV shutdown |url=https://www.gmanetwork.com/news/scitech/technology/894217/ntc-preparations-underway-for-analog-tv-shutdown/story/ |access-date=2024-01-16 |website=GMA News Online |language=en}}</ref><ref name=":2">{{Cite web |last=Dela Cruz |first=Raymond Carl |date=January 15, 2024 |title=NTC urges switch to digital TV as analog shutdown looms |url=https://www.pna.gov.ph/articles/1216971 |access-date=January 16, 2024 |website=Philippine News Agency}}</ref><ref name=":3">{{Cite web |last= |first= |date=2024-01-15 |title=NTC URGES PUBLIC TO EMBRACE DIGITAL TV AS ANALOG SHUTDOWN NEARS |url=https://maharlika.tv/ntc-urges-public-to-embrace-digital-tv-as-analog-shutdown-nears/ |access-date=2024-01-17 |website=Maharlika NuMedia |language=en-US}}</ref> It will simulcast in [[Company:ISDB#ISDB-T|ISDB-T]].)
* {{flag|Puerto Rico}}<ref name="HegartyPhelan1998"/> (now uses ATSC)
* {{flag|Saint Kitts and Nevis}}<ref name="HegartyPhelan1998"/>
* {{flag|Saint Lucia}}<ref name="HegartyPhelan1998"/>
* {{flag|Saint Vincent and the Grenadines}}<ref name="HegartyPhelan1998"/>
* {{flagcountry|Saudi Arabia}} (simulcast in NTSC, SECAM and PAL, before switching to PAL in the early 1990s)
* {{flag|Sint Maarten}}<ref name="HegartyPhelan1998"/> (also used 8&nbsp;MHz spacing of DVB-T2 (same bandwidth spacing in European Netherlands) on Encrypted Terrestrial Digital TV subscription via WTN CABLE)
* {{flag|South Korea}}
* {{flag|Suriname}}<ref name="HegartyPhelan1998"/>
* {{flag|Trinidad and Tobago}}<ref name="HegartyPhelan1998"/> (Will convert to ATSC 3.0 instead of 1.0. The conversion will begin in 2023 and is expected to be completed by 2026.<ref name="TT ATSC 3.0">{{cite web |title=Notice |url=https://tatt.org.tt/Home/Announcements4/ReadMore/tabid/350/ArticleId/677/Notice-22.aspx |website=Telecommunications Authority of Trinidad and Tobago |access-date=2022-01-26}}</ref>
* {{flag|Turks and Caicos Islands}}<ref name="HegartyPhelan1998"/>
* {{flagcountry|United States}}<ref name="HegartyPhelan1998"/> (Full-power over-the-air NTSC broadcasting was switched off on June 12, 2009<ref>{{cite web |title=Senate Passes Bill to Shift DTV Transition Date to June 12 |url=http://commerce.senate.gov/public/index.cfm?FuseAction=PressReleases.Detail&PressRelease_Id=84452e41-ca68-4aef-b15f-bbca7bab2973 |archive-url=https://web.archive.org/web/20090210110616/http://commerce.senate.gov/public/index.cfm?FuseAction=PressReleases.Detail&PressRelease_Id=84452e41-ca68-4aef-b15f-bbca7bab2973 |url-status=dead |archive-date=February 10, 2009 |access-date=January 27, 2009}}</ref><ref name="ATSC SALUTES THE PASSING' OF NTSC">{{cite web |title=ATSC SALUTES THE 'PASSING' OF NTSC |url=http://www.atsc.org/cms/index.php/communications/press-releases/90-atsc-salutes-the-passing-of-ntsc |archive-url=https://web.archive.org/web/20100524235632/http://www.atsc.org/cms/index.php/communications/press-releases/90-atsc-salutes-the-passing-of-ntsc |publisher=NTSC |archive-date=May 24, 2010 |access-date=June 13, 2009 |url-status=dead}}</ref> in favor of ATSC. [[Physics:Low-power broadcasting|Low-power stations]], Class A stations were switched off on September 1, 2015. [[Engineering:Broadcast relay station|Translators]] and other [[Physics:Low-power broadcasting|Low-power stations]] were supposed to transition on the same day Class-A stations shut off analog services but it was postponed to July 13, 2021, due to a [[Physics:Spectrum auction|spectrum auction]].<ref>{{Cite web|url=https://apps.fcc.gov/edocs_public/attachmatch/DA-17-442A1.pdf|title=FCC Public Notice: "THE INCENTIVE AUCTION TASK FORCE AND MEDIA BUREAU ANNOUNCE PROCEDURES FOR LOW POWER TELEVISION, TELEVISION TRANSLATOR AND REPLACEMENT TRANSLATOR STATIONSDURING THE POST-INCENTIVE AUCTION TRANSITION", May 17, 2017|website=Apps.fcc.gov|access-date=February 22, 2022}}</ref> Most remaining analog [[Engineering:Cable television|cable television]] systems are also unaffected.)<ref name="apps.fcc.gov">{{cite web|url=http://apps.fcc.gov/ecfs/document/view?id=60000976623|title = ECFS|website=Apps.fcc.gov}}</ref>
* {{flag|United States Virgin Islands}}
* {{flag|Venezuela}}<ref name="HegartyPhelan1998"/>
{{div col end}}

=== Experimented ===
* {{flag|Brazil}} (Between 1962 and 1963, Rede Tupi and Rede Excelsior made the first unofficial transmissions in color, in specific programs in the city of São Paulo, before the official adoption of [[PAL-M]] by the Brazilian Government on February 19, 1972)
* {{flag|Paraguay}}
* {{flag|United Kingdom}} (Experimented on 405-line variant of NTSC, then UK chose 625-line for PAL broadcasting.)

=== Countries and territories that have ceased using NTSC ===
The following countries and regions no longer use NTSC for terrestrial broadcasts.

{| class="wikitable sortable"
|-
! Country
! Switched to
! Switchover completed
|-
| {{BER}}
| [[DVB-T]]
| <span style="display:none">2016-03-01</span>March 2016
|-
| {{CAN}}
| [[ATSC standards|ATSC]]
| <span style="display:none">2012-07-31</span>August 31, 2011 (Select markets)
|-
| {{JPN}}
| [[Company:ISDB#ISDB-T|ISDB-T]]
| <span style="display:none">2012-03-31</span>March 31, 2012
|-
| {{KOR}}
| [[ATSC standards|ATSC]]
| <span style="display:none">2012-12-31</span>December 31, 2012
|-
| {{MEX}}
| [[ATSC standards|ATSC]]
| <span style="display:none">2015-12-31</span>December 31, 2015 (Full Power Stations)<ref>[http://www.cft.gob.mx/work/models/Cofetel_2008/Resource/11244/TDT_Decreto_2010_09_02.pdf Transicion a TDT (Transition to DT)] {{Webarchive|url=https://web.archive.org/web/20100919102452/http://www.cft.gob.mx/work/models/Cofetel_2008/Resource/11244/TDT_Decreto_2010_09_02.pdf |date=September 19, 2010 }} (Spanish)</ref>
|-
| {{TWN}}
| [[DVB-T]]
| <span style="display:none">2012-06-30</span>June 30, 2012
|-
| {{USA}}
| [[ATSC standards|ATSC]]
| <span style="display:none">2009-06-12</span>June 12, 2009 (Full Power Stations)<ref name="ATSC SALUTES THE PASSING' OF NTSC"/> <br />September 1, 2015 (Class-A Stations)<br />July 13, 2021 (Low Power Stations)
|}

== See also ==
* [[Engineering:Broadcast-safe|Broadcast-safe]]
* [[Composite artifact colors]]
* Glossary of video terms
* {{slink|List of common resolutions#Television and media}}
* [[List of video connectors]]
* [[Moving image formats]]
* [[NTSC-C]]
* [[Engineering:Television channel frequencies|Television channel frequencies]]
** [[Engineering:Very high frequency|Very high frequency]]
** [[Physics:Ultra high frequency|Ultra high frequency]]
** [[Physics:Knife-edge effect|Knife-edge effect]]
** Channel 1 (North American TV)
** [[Engineering:Channel 37|Channel 37]]
** Pan-American television frequencies
** Australian and New Zealand television frequencies

== References ==
{{reflist}}

== Sources ==
* A standard defining the NTSC system was published by the [[Organization:International Telecommunication Union|International Telecommunication Union]] in 1998 under the title "Recommendation ITU-R BT.470-7, Conventional Analog Television Systems". It is publicly available on the Internet at [http://www.itu.int/rec/R-REC-BT.470/en ITU-R BT.470-7] or can be purchased from the [http://www.itu.int ITU].
* Ed Reitan (1997). [https://web.archive.org/web/20050205064527/http://www.novia.net/~ereitan/Color_Sys_CBS.html "CBS Field Sequential Color System"]

== External links ==
* [http://www.ntsc-tv.com/ National Television System Committee]
* [http://www.jneuhaus.com/fccindex/cablech.html US cable television channel frequencies]
* [http://www.tvtower.com/Commercial%20Television%20Frequencies.html Commercial Television Frequencies] – at TVTower.com<!--registration needed-->
* [http://www.paradiso-design.net/videostandards_en.html Representation of the NTSC refresh rate on a television and on a DVD]
* {{webarchive |url=https://web.archive.org/web/20140222023017/http://www.avsforum.com/t/223615/does-59-94-hz-60-hz |title=Why 59.94 vs 60 Hz}}

{{TV resolution}}
{{Video formats}}
{{SMPTE standards}}
{{Color space}}
{{Analogue TV transmitter topics}}
{{Telecommunications}}

[[Category:Television terminology]]
[[Category:Television transmission standards]]
[[Category:Video formats]]
[[Category:Video signal]]

{{Sourceattribution|NTSC}}