Prefecture-level City Cable Digital Tv Platform Design

The digital television (DTV) is the outcome of the digital information technique revolution. While providing more and better programs to satisfy audiences' increasing demands, DTV is stimulating the relevant industries, such as the content producing, the electronics manufacturing, the software service etc. The fast development of the related industry will produce a huge economic performance. It will play important role in the economy and society developments. With the rapid development of DTV,analog TV will be replaced gradually. China government has already announced the timetable to develop DTV, it can say, the digital television ages has already come. Our country owns more than 120,000,000 CATV customers with more than 470,000,000 analog TV sets, which is the biggest number in the worldo But only in the province class cities currently are being run digital television business, and the number of digital subscribers is about 12 million. The cabled TV operators in lower class cities are still running analog business. Along with the change of time, the need that lower class cities' CATV network companies urge to construct digital television platforms will come to be strong more and more .Because of the national particularity, local CATV networks can't imitate the abroad DTV platform construction mode. They have to start with low cost, carry out basically functions first, then upgrade and expand gradually. So how to design and construct the early digital television platforms has become the important topic.This thesis mainly aimed at lower class city CATV digital platforms design. First, it introduced the digital television signal coding and modulation techniques for transmitting, program streams multiplexing and demultiplexing technology, scrambling and encrypting principle, Then it analyzed and studied the network environment, the system function and the system structure. And then it explored the platform design thought of the electronical program guide system (EPG), subscriber management system (SMS) and the conditional access system (CA) etc. At last it put forward a concretely project design that keeping both of the analog and digital television in the transition period. In the meantime .It also put forward a solution to some critical problems.