Digital Television System Multiplexer Program Clock Reference (pcr) Calibration Of The Realization

With the transformation of analog television to digital television, a digital television broadcast system will become a necessary platform in the future. By the new platform, the quality of television program has been improved remarkably, and the availability of resources also has been increased. The digital television system is a live transmission system. To guarantee system's normal work, the receiving end must be consistent with the transmitting end in frequency and phase. But in the actual situation, the timing clock of the receiving decoder at the rear end is not, in general, synchronous with that of the transmission encoder at the front end. Therefore there must be an establishment of a PCR (Program Clock Reference) for the program clock reference, to fulfill the real-time adjustment. By unifying two transmission streams into one at a multiplexer, PCR adjustment is completed in the RTL level, and the hardware for the PCR adjustment is designed.The thesis has first introduced the MPEG-2 standard agreement, analyzed the data transmission stream, the structure of the frame, and the receiving module and the transmitting module, the bus cycle and the interface signals. An important contribution of the thesis is the PCR adjustment by unifying two transmission streams into one at the multiplexer and the functional module division for the adjustment. The PCR adjustment processing unit is composed of six parts, i.e. the receive module, the program reference clock processing module, the buffer module, the transmission module, the flow control module and the serial port agreement module. The structure design for the six modules is presented in detail, and verified by simulations. Download to FPGA circuit board make a test validation.The output of the multiplexer PCR of the transmission stream is fed to a PC machine through a serial port, the result is then compared with that of the symbol stream analyzer from the uncorrected stream. The test indicates that the hardware realization satisfies the requirements of digital television program.