The evolution towards high-definition television

The paper discusses the impact on our multimedia society of the recent practice of using different TV standards for the various parts of the chain from studio to receiver. This trend to optimize the standard for each stage rather than stick to one standard throughout paves the way for the evolutionary approach to HDTV. High-definition studio sources will also have to provide signals for existing terrestrial networks as well as the newer media distribution methods such as cable, DBS, tape, and disc. The paper discusses the relationship of possible HDTV studio standards to these other channels and attempts to quantify, the magnitude of the problems of achieving compatibility and "transparency." The main question of compatibility is identified as the need to solve the problem of using the same studio source as a signal for 60- as well as 50-Hz transmissions. "Transparency" can be achieved in a compatible way by adding bandwidth to carry the higher definition. However, if sophisticated bandwidth reduction techniques using picture storage in the receiver are to be used to achieve optimum spectrum usage a new starting point of standardization for transmission is required.