The Digital Television Conditional Access System Suitably Matches Levels Research And Realization

The digital television receiving system refers the system which can receive and broadcast the digital television signal. It includes the MEPG2 demodulation module, the numeral regards the audio frequency coder and the conditional access module and so on. The conditional access system modules are developed specially then transplants to the digital television receiving system. Different district will choose the conditional access system to carry on the program encryption, to develop a digital television receiving system, transplantation of different conditional access systems are needed for the different district. Therefore, the transplant conditional access system development cycle plays the decisive role to the overall system development cycle, this article studies on a new method of transplant access system to add a new software adapter level during the process of transplant, the main work includes:After analyzed the principle of work and process of conditional accessing system, transplants the various conditional accessing system to the digital television receiving system, analyzed the compiled code required for the process of transplant, combine the principle of work and process of conditional accessing system, be aimed at transplanting conditional accessing system can only allow single conditional accessing system work normally. Arrange and produce a new software adapter, and design seven difference modules according to the function of conditional accessing system, according to the function need to achieve for each module, process a concrete analysis.This research realized the method of adapter of read-write smart card. In adapter layer, it totally matched the protocol and also can determine the type of protocols. In the read-write adapter layer, the adapter layer can determine the parameters of protocol and read and write command. It enables the communication between the smart card and the other modules of digital television receiving system through the adapter layer.This research realized the method of adapter of setting descrambler, compile an adapter modules to solve the problem of different method of scrambler. Determine scrambler and unify data interface through the adapter layer, to enable different type of conditional access system to set the descrambler by retrieving the descrambler code.This research realized the track monitor system of CA glue, could suitably match all different conditions receiving system, the realization of this module used the interior of examination system to define the track, again add to the transplant condition receiving system, this avoided the problem on difficulty of tracking due to dissimilar parameter name or the mode of working of conditional accessing system.