SMPTE 244M-2003

This standard describes a bit-parallel composite video digital interface for systems operating according to the 525-line, 59.94-Hz NTSC standard, as described by SMPTE 170M, sampled at four times color subcarrier frequency. Sampling parameters for the digital representation of encoded video signals, the relationship between sampling phase and color subcarrier, and the digital levels of the video signal are defined.This standard has application for use with shielded twisted 12-pair cable of conventional design over distances up to 50 m, without transmission equalization or any special equalization of the receiver. Longer cable lengths may be used, but with rapidly increasing requirement for care in the cable selection and possible receiver equalization or the use of active repeaters or both. Digital composite video signals, as defined by this standard, are the signals conveyed by the composite implementation of the serial digital interface. It should be noted that additional information to that described by this standard is also carried by the serial digital interface.The serial digital interface is the preferred method for the interconnection of composite digital equipments when cable lengths exceed 50 m.