What is NTSC 4.43 system?
NTSC 4.43 is also known as NTSC-J. NTSC 4.43 is a pseudo color system which transmits NTSC encoding (525/29.97) in a color subcarrier of 4.43 MHz instead of 3.58 MHz.
The resulting output is only viewable by TVs which support the resulting pseudo-system (usually multi-standard TVs). Using a native NTSC TV to decode the signal yields no color.
The format is apparently limited to few early 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. 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.
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 need 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.