DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

NTSC-4.43 The NTSC-4.43 scheme, sometimes called pseudo-NTSC
or hybrid-NTSC, enables playback of 480i NTSC material
on a monitor optimized for 576i PAL. The playback
signal uses 480i scanning. Chroma is modulated using
the NTSC method, but onto the 4.43 MHz color subcarrier
frequency of PAL. (There is no PAL V-axis switch.)
A monitor capable of NTSC-4.43 operation requires
a vertical lock range sufficient to accommodate the
59.94 Hz field rate. The monitor’s 4.43 MHz color
subcarrier crystal is used to demodulate chroma;
a 3.58 MHz crystal is unnecessary.
PAL 60 PAL 60, sometimes called quasi-PAL, hybrid-PAL, or
pseudo-PAL, enables playback of 480i NTSC material on
a monitor optimized for 576i PAL. As in NTSC-4.43,
video is played back with 480i scanning. Chroma is
modulated using the PAL method onto the 4.43 MHz
subcarrier frequency of PAL. A monitor capable of
PAL 60 requires a vertical lock range sufficient to
accommodate the 59.94 Hz field rate. The monitor’s
4.43 MHz color subcarrier crystal is used to demodulate
chroma; a 3.58 MHz crystal is unnecessary. PAL 60
is comparable to PAL-M, except that PAL-M’s precise
ratio of f SC to f H is not maintained.
NTSC 50 This scheme enables playback of 576i PAL material on
a monitor optimized for 480i NTSC. Video is played
back with 576i scanning. Chroma is modulated using
the NTSC method onto the 3.58 MHz subcarrier
frequency of NTSC. An NTSC 50-capable monitor
requires a vertical lock range sufficient to accommodate
the 50 Hz field rate. The monitor’s 3.58 MHz color
subcarrier crystal is used to demodulate chroma;
a 4.43 MHz crystal is unnecessary. NTSC 50 is comparable
to PAL-N; however, chroma is modulated using
the NTSC method, not PAL, and PAL-N’s precise ratio of
f SC to f H is not maintained.
A consumer-grade digital decoder can easily handle all
of these schemes, by separating scanning from chroma
demodulation, so as to mimic the processing done by
a consumer television receiver.
580 DIGITAL VIDEO AND HDTV ALGORITHMS AND INTERFACES