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ATSC Highlights Recent Published Standards

A number of new documents have been published by ATSC that are of particular interest to broadcasters. Some key developments over the past couple of months include the "ATSC Mobile DTV Candidate Standard, Parts 1–8" (A/153), "Conversion of ATSC Signals for Distribution to NTSC Viewers," and the "Advanced Common Application Platform, Revision A" (ACAP).


ATSC Mobile DTV is being developed to support a variety of services including free (advertiser-supported) television and interactive services delivered in real-time, subscription-based TV, and file-based content download for playback at a later time. The standard may also be used for transmission of new data broadcasting services such as real-time navigation data for in-vehicle use. This document set is currently in its fourth update. A/153 is modular in concept, with the specifications for each of the modules contained separate parts, specifically:

Part 1—"Mobile/Handheld Digital Television System"
Part 2—"RF/Transmission System Characteristics"
Part 3—"Service Multiplex and Transport Subsystem Characteristics"
Part 4—"Announcement"
Part 5—"Presentation Framework"
Part 6—"Service Protection"
Part 7—"Video System Characteristics"
Part 8—"Audio System Characteristics"

Part 1 of A/153 includes an overall system description and serves to tie the other parts of the document together.

"Conversion of ATSC Signals for Distribution to NTSC Viewers" (A/79) is a Recommended Practice that provides guidance to broadcasters and other creators of ATSC high-definition or standard-definition content and to the operators of Multichannel Video Programming Distributor (MVPD) systems (such as cable or direct-to-home satellite). It recommends the equipment capabilities needed to provide the highest quality programming to viewers who only receive NTSC services.

ACAP (A/101A) is an interactive TV (ITV) standard developed by the ATSC in conjunction with CableLabs that is optimized for terrestrial broadcast and compatible with cable industry methods of ITV carriage. ACAP defines the technical details needed by content providers, broadcasters, cable and satellite operators, and consumer electronics manufacturers to develop interoperable services and products that provide consumers with advanced interactive services.

ACAP is important because it provides a single method of delivering interactive applications to terrestrial receivers and cable set-top boxes. Revision A addresses issues identified during a demonstration effort undertaken by the ATSC Planning Committee designed to illustrate how ACAP can be used to enhance the viewing experience.

ATSC documents can be downloaded at no charge from the ATSC Web site,


In addition to the ongoing work on the A/153 ATSC Mobile DTV Candidate Standard, work is under way in other ATSC specialist groups on standards and recommended practices important to broadcasters.

First up is the "Program and System Information Protocol for Terrestrial Broadcast and Cable" (A/65). A full revision of this standard was at final ballot as this issue went to press. Revision D rolls up a previously approved amendment and a number of items identified over the past few years.

Another item currently underway is the "Program and System Information Protocol Implementation Guidelines for Broadcasters" (A/69). The ATSC Specialist Group on Data Multiples/Transport (TSG/S8) is conducting a comprehensive review and updating of A/69, first published in 2002. It is expected that an updated version of this important Recommended Practice will be completed and published before the end of this year.

Lastly, a revision of the Recommended Practice, "Design of Synchronized Multiple Transmitter Networks" (A/111), has been developed to expand upon information relating to distributed translator networks. If all goes as planned, this update should be finalized and available before the end of the year.


Work within ATSC is open to all organizations with a direct and material interest. If you would like to be involved ongoing work within ATSC, please contact the author.

Jerry Whitaker is vice president of standards development for the ATSC. You can reach him via TV Technology.