
Color-under recording was intro-
duced in U-matic VCRs, using
a low-frequency subcarrier of
approximately 688 kHz. A
dub
connector
carried separate luma
and chroma components; this
interface was known as
Y'/C688.
The original VHS VCRs used
a low-frequency subcarrier at
about 629 kHz, and some indus-
trial equipment implements the
corresponding Y/C629 interface.
(Chroma carrier frequency in Hi8
VCRs is approximately 743 kHz.)
the original video, so this mixing destroys the coher-
ence of subcarrier and line rate. Chroma, now on
a 3.58 MHz subcarrier, is summed with luma to
produce the composite ...