Planning and design of a cable television system for Malta

Abstract

Originally, television was conceived of as another method of broadcasting entertainment and news programmes but with pictures. However the ability to reproduce pictures, text material, graphics and other information has become so useful so that now it is an integral part of today's society. Early cable TV systems were quite simple. Their function was to provide television signals in areas where 'off-the-air' reception was either unavailable or unsatisfactory. Signals from the cable were of poor quality by today's standards. Almost any television picture was considered better than no picture at all. In recent years cable TV is no longer considered a substitute for 'off-the-air' reception. Cable systems serve all types of communities, even those where several good quality signals can be received on a modest home antenna. It is being widely recognised that cable TV not only provides more and better pictures in almost any location, but also offers more entertainment and facilities. A cable system may have a two way capability that of opening the way to a wide variety of services that were not possible a few years ago. For many years the cable TV systems have been using the coaxial cable as its medium for signal transport and is still in use, although lasers and fibre optics are generally considered as vital for all new systems. The extent of fibre use in the cable system architecture of the eighties was largely restricted to super trunking and limited trunking applications. This was attributed to the high cost and limited availability of fibre and optoelectronics. The transmission technique was frequency modulation on fibre and this application was only as an alternative to microwave. The use of fibre over coaxial was to counteract the possibility of failure, power-surges, and reduce maintenance service. The bandwidth is potentially higher since the carrier of information in the optical waveguide is an electromagnetic radiation. In 1988 , the advent of the distributed feedback laser (DFB) for CATV applications (cable television), provided an alternative modulation technique. This is AM broadband technology which eliminates all signal processing required under FM. This has established vast market potential for designers to make use of high performance AM optoelectronics. These recent developments have now altered the economic and technical outlook for widespread application in the cable design. The opportunities that AM technology now offers in improving the quality , reliability and capability of the cable plant are given all the importance in my thesis.