scope:

This report provides analog interface and performance objectives for contribution application of television transmission service channels employing DS3 transport. Television signals created or transmitted in accordance with other standards or recommendations may not necessarily be compatible with the provisions of this report.

Specifically, this report addresses the carriage of 525-line, unencrypted System M-National Television Systems Committee (NTSC) color or monochrome video signals (including users' vertical and horizontal blanking intervals) and their associated audio signals only. The performance objectives take into account the presence of a single encoding and decoding between the end points of a channel. Performance definitions and measurement methods are provided where appropriate. Electrical interface definitions are provided to facilitate compatibility between end users, service providers, and carriers.

The performance characteristics identified within this report apply to the transmission quality between the defined interfaces. Those interfaces are (1) between transmission service providers and end users, and (2) between the jurisdictions of one transmission service provider and another. This report defines neither the interconnection nor the performance characteristics of specific apparatus or equipment.

The test methods and performance objectives contained in this report are futuristic and forward looking in nature and are not necessarily intended to apply in every case to equipment that exists as of the date of publication of the document. The validity of the parameters and objectives, when applied to new coding systems, must also be verified relative to their ability, either singularly or as a set, to indicate objectively the acceptability of that coding system in terms of its objective performance. In this respect, the objectives in this document must be considered as preliminary.

This report makes no assumption as to the specific type of television coding algorithm (i.e., DPCM, DCT, etc.). Recognizing that television signal encoding and decoding technology is in many respects not yet mature, it should be appreciated that not been possible in this report to exhaustively identify every potential performance degradation and the measurement techniques and objectives to properly quantify such degradation. It is also not possible to prove prior to the definition of a new coding process whether or not the measurement techniques and performance objectives given in this report are critical or appropriate indicators of subjectively acceptable performance. Therefore, the user of this report is cautioned that additional parameters and measurements not in this report may be needed, and that the validity of those that are given in this report should be evaluated prior to adoption for evaluation of the analog performance of television service channels employing DS3 transport.

Purpose.

The purpose of this report is to provide a preliminary set of static and dynamic analog parameters for contribution application of television signals transported over DS3 facilities. It is intended to provide a common basis for the understanding and advancement of techniques for users and suppliers of this technology.

Application.

This report applies to the analog interface and performance objectives for DS3 transport of contribution application system M-NTSC television signals. Services employing this technology are used to transport both the audio and video portions of television signals.

This report does not apply to services intended for videotelephony, video teleconferencing, and video information distribution, which may use motion-compensated differential-transform digital video coding according to such standards as CCITT Recommendation H.261 "Video Codec for Audiovisual Services at p X 64 kbit/s", ANSI T1.314-1991 "Digital Processing of Digital Signals - Video Coder/Decoder for Audiovisual Services at 56 to 1,536 kbit/s", or ISO 11172 "Coding of Moving Pictures and Associated Audio".