The Research Of Digital MMDS TV System Based On DVB-S Standard

Multichannel Microwave Distribution System is one of ripe microwave communication techniques in the field of wireless radio and television communication. It is also called wireless cable or sky cable. Analog MMDS system is one of main techniques often used in the engineering of wireless radio and television covering in our nation. Less investing, fast construction, high quality signal and convenience maintenance are its four big characters. With rapid development of economic power in our nation, peoples' requirement for amount and quality of radio and television is more and more. Meantime, many modern techniques of radio and television such as CATV, CADTV, IPTV are born in short time, analog MMDS system have couldn't satisfied the requirement of subscribers, in this case, digital MMDS system is born in time. It has the charactertics of high ratio of using spectrum, high quality signal, wider covering and less investing, and realize transformation from analog system to digital system. So it has become one of good solution in the engineering of "every village interconnection".There are two kinds of digital MMDS system according to different standards, one is based on DVB-C standard; another is based on DVB-S standard. They are all could apply but have some different characters in technique. This paper concretely states digital MMDS system based on DVB-S standard .Design research of the system is one of key points in this paper. It analyses demands and defines rules of design in the system, then particularly introduces the whole design with eight aspects, including system constitutes, amount and content of programme, configuration of frequency, analysis and caculaiton of signal characters, caculaiton of signal link and so on. One of point worth to notice, this system has CA system and SMS system. The two systems could realize safe encoding for signal, complex management for subscribers and intelligent paying. In the meantime, it supplies a wide room for developing value added service.Construction of the system is another main part in this paper. It particularly states composition and requirement of devices for three parts, which are headed part, transmission part and ended receiving part. This paper also introduces some important problems in the practice construction, so supplies precious experiences for engineers and workers.According to statement in this paper and operation of digital MMDS system which tested in one city of Shandong provience, we could have a conclusion: digital MMDS system based on DVB-S standard is one of good solution for television covering all the area of country. It is worth to be applied and spreaded widely. Meantime, it has good social benefit and economic benefit.