SMPTE RP 174:1993

Abtract:

This practice describes the means of interconnecting digital video equipment operating in system M (525/60) and complying with the 4:4:4 encoding parameters as defined in CCIR Recommendation 601-2, annex 1 with a nominal sampling frequency of 13.5 MHz. Provision is made to convey signal at 10-bit precision and to carry a fourth auxiliary channel as part of the signal multiplex (yielding 4:4:4:4 or 4×4 overall). The practice has application in the television studio over distances up to 100 m (320 ft). The characteristics of the interface are summarized below: (1.1) The video signal is transmitted in the form of three color-component signals and an auxiliary signal (G, B, R, and A or Y, C
B
, C
R
, and A). (1.2) The video signal is transmitted at the 4:4:4 family level of CCIR 601-2, with a nominal sampling frequency of 13.5 MHz. Provision is made to convey signals at 10-bit precision. (1.3) The bits of the digital code words that describe the video signal are transmitted in a parallel arrangement using 10 conductor pairs. Each pair carries a multiplexed stream of bits (of the same significance) of each of the component signals. Accordingly, the bit rate used in each pair is nominally 54 Mbits/s. An eleventh conductor pair carries a clock signal at 54 MHz. (1.4) The signals on the interface are transmitted using balanced conductor pairs for a distance up to 25 m (80 ft) without equalization and up to 100 m (320 ft) with appropriate equalization. (1.5) The interface consists of one transmitter and one receiver in a point-to-point connection. (1.6) Parameters of the signal format are chosen to facilitate conversion to and from a serial digital interface format. (1.7) The interface allows the transmission of appropriate ancillary signals that may be multiplexed into the data stream during video blanking intervals. (1.8) Where hexadecinal values are used, they are indicated by a subscript h, such as 3FF
h
; other values are decimal.