Research And Implementation Of Cable Digital Television Conditional Access System

With the rapid development of cable digital television，a gradual disappearance ofanalog television of cable television. Conditional access system CAS has got theextensive application in cable digital television. CAS is a indispensable subsystem todigital TV.This thesis took the CA technology in the profession application as abackground, has researched and implementation CA technology, and realized theconditional access technology in the project construction in Zuny city cable digitaltelevision of Guizhou province.First, the author compared the traditional analogue television technology to cabledigital television technology. Next, the author analyzed the CA technology which hasplayed an important role in the development of the digital television. Author gotanalysis approach the logica structure of CAS. Focuses on the analysis of solving theproblem of scrambling digital television，descrambling of set-top cable box STB. Toset up the conditional access system, managing set-top box and television smart card,scrambling and accrediting the TV program. It also provides a basis for managingdigital TV consumers more effectively and more efficiently. This thesis make a projectto solve this problem.It includes Synchronization between ECM and control,communication between the CA and program scrcramble. It analyses the bandwidth ofconditional access and the realization form of EMM and ECM. Last, the thesis hasrealized the CA simulcrypt and multicrypt, accrediting the smart card, systemaddressing, and made to raise the bandwidth.It realized the interconnection of CAS andSMS. It also made the accreditation safe and reliable.The paper research’s content has succeeded applied in constructing of Zunyi citydigital televison conditional access service system. It has been tried the movement formore than a half year time, the system has satisfied the design requirements completely.