Research And Implementation Of The Demux Module In CAM Card

The DEMUX module presented in this paper is the conditional access module card(CAM)seperated from DTV card and is used for the transport stream DEMUX. Because the MPEG II standard systematic level is adopted for the criterion of digital television program in our country, the DEMUX in this paper is designed according to the MPEG II standard, and mainly includes the following parts: The transmission flows input and output buffers FIFO, PID filters module, the interface module of the descramble module (DCA), the interface module of the section filters(SECTION), and the CPU mainline interface module (including the interface of configuring RAM). The main function is the DEMUX for transmission flows, PID filters, CW providing, as well as SECTION filters. In the design for the MPEG II section filters, we have changed the former software filter to hardware filter for the interface module of the partition (SECTION), thus reduced the CPU load, greatly enhanced the operational speed. Adopting the synplify7.3 to synthesis the RTL code for this module design and ISE5,2 for layout, the results are that its clock frequency of TS flows > 10MHz, the clock frequency of CPU >40MHz, and the clock frequency of internal work > 90MHz with XILINX VIRTEX-II XC2V1000-4BG575 FPGA .The final verifications of PSI and TS show that the DEMUX module developed in this thesis is in accordance with the demand of design.