18.4.1 Introduction

The following is a brief description of all the new television formats developed over the last decade or so; its purpose is to illustrate the choice facing a broadcaster during this period when contemplating new services. In the context of satellite television not all of these standards have proved to be useful or practical but they certainly have influenced the decisions of the programme providers and the receiver manufacturers who supply the essential parts of a practical system. In the broadcasting chain the fundamental commercial transaction is between the programme provider and the viewer; all other parties are middle men in the process. The choice of medium and technology standard will be influenced strongly by the extent to which any system helps or hinders this basic transaction.

18.4.2 High-Definition Television

Unfortunately, HDTV is a term which can, and does, mean all things to all men. From a technical viewpoint, HDTV is about image resolution, where the number of lines is a primary parameter from which others are derived, and resultant picture quality must be in some sense better than what is already available23.

The CCIR, when it began studying HDTV in the mid-1980s, defined HDTV systems as those with more than 1000 scanning lines. At that time the world broadcasting community was seeking a single world standard, a very laudable and worthy objective, but one fraught with political and practical difficulties. There were several proposals for HDTV standards and these included:

• 1250 lines (Europe);