“Infrastructure for an NTSC/ATSC-Supported Nationwide Data Broadcasting Service: Present and Future”

This paper reviews the implementation and operation considerations to support a nationwide data broadcasting transmission architecture for non-program related data. It reviews architectures utilized by PBS National Datacast: VBI, dNTSC and migration to DTV. The network management requirements to support the data delivery are also discussed. For over ten years, PBS National Datacast (NDI) has been embedding data streams into existing PBS analog broadcast signals through the use of the Vertical Blanking Interval (VBI), and has been datacasting a variety of multimedia services. Currently NDI delivers data via 260 of the total 348 TV transmitters in the PBS system. While VBI has provided a viable option in the past and continues to provide a niche for certain applications, the data environment today demands more bandwidth, and savvy users utilize multiple applications requiring varied types of data. The next step for PBS National Datacast (NDI) is the implementation of the Dotcast dNTSC (data in NTSC video) technology. The Dotcast system uses patent-pending technologies that can inject a 4.5 Mbps digitally encoded data stream into an NTSC broadcast television signal without degrading the signal or interfering with regular TV reception. The dNTSC system can make valuable use of existing NTSC assets, and provide a smooth transition path to DTV data broadcasting. This paper lays the framework for a data broadcasting architecture where multiple data services are vying for a piece of the transport stream, and local data broadcasting opportunities at the station will be competing with national opportunities for bandwidth.

Published

2001-02

Content type

Original Research

DOI

10.5594/M00360

ISBN

978-1-61482-934-8