Editing NTSC (section)

=== 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 |last1=Poynton |first1=Charles |url=https://books.google.com/books?id=rsEwE2X3cFAC&dq=NTSC+4.43&pg=PA580 |title=Digital Video and HD: Algorithms and Interfaces |publisher=Morgan Kaufmann |year=2003 |isbn=9781558607927}}</ref> The resulting output is only viewable by TVs that support the resulting pseudo-system (such as most PAL TVs).<ref>{{cite web |title=WeetHet - Video - Overview of available formats |url=https://www.weethet.nl/english/video_formats.php |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 [[United States Air Force|USAF]] TV based in Germany during the [[Cold War]] and [[Hong Kong Cable Television]].{{Citation needed|date=February 2024}} It was also found as an optional output on some [[LaserDisc]] players 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".

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 lines/29.97 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.