Digital Cinematography, 2nd Edition

Color 53

electronic timing parameters of standard deni-

tion digital TV. For the purposes of doing efcient

standards conversions between PAL and NTSC,

it made sense to design the timing, or sampling of

both standards, from a common point of refer-

ence. A 2.25 MHz frequency is the lowest common

multiple between NTSC and PAL systems for digi-

tal sampling. Six times 2.25 equals 13.5 MHz, so

that number was internationally decided upon as

the (over) sampling rate used for both PAL and

NTSC formats in standard component digital

video. HDTV maintains an integer relationship for ...