The Transition to Digital Television Distribution Systems: A Technological View of Expected Interoperability *

This chapter describes the technological status of digital television distribution systems in the United States at the end of the summer of 1995. Given that this technology is in the early development and deployment stage, such a "snapshot" of the situation suffers from some lack of documented technical information on different systems. Despite this drawback, however, the chapter is able to identify and discuss several similarities and differences among the existing and proposed digital television compression systems of direct broadcast systems providers, cable-television operators, and over-the-air broadcasters. Such a comparison of system characteristics provides a useful inference of the degree of interoperability that might be reasonably expected across the different distribution systems over time. The transmission layer provides the transmission and channel coding portion of the digital video distribution system. In cases, where interoperability is not feasible, compatibility among systems should emerge as equipment is built to bridge the interoperability gaps.