Design On Digital Video Format Conversion Interface Used In Long-distance Transmission

At actual digital television program recording process, Direct output of the camera are serial YCrCb component video signal, because the market does not exist digital displays with corresponding video interface, so the recording process could not be monitored in real time, the effect of the program could only be checked after all recording work, so some programs even necessary to carry out the second recording. This has seriously affected the television and other units of work efficiency. On the other hand, because the transmission path require long distance, so the problem of signal transmission distance must also be solved.Aiming at the problem above, an interface circuit is designed based on FPGA (Field Programmable Gate Array) to convert ITU-R BT.656 SDI(Serial Digital Interface) signal to DVI(Digital Visual Interface) signal without influence on long-distance transmission. It is solved that recording result can be checked only after the recording is over, and the efficiency of work of TV station is improved. The main job done as follows:Adopt GS1574A automatic cable equalizer to complete cable equalization. Adopt GS1575A multi-rate SDI automatic reclocker to automatically recover the embedded clock from the digital video signal and re-time the incoming video data. Adopt LM0031 digital video deseriablizer to complete serial-to-parallel data conversion and parallel clock extraction.The design, used Altera Cyclone FPGA as the main control chip, adopt modular design method and implemented the whole process of color space conversion, including synchronization extraction and data demultiplex module design, color space conversion module design, Resolution conversion module design, asynchronous FIFO module design, Ping-pong operation and SDRAM controller module design, Video transmission module design and so on. The software is developed by Quartus II 4.2 debugger, used top to bottom method to design, and used Verilog HDL Hardware Description Language to program.Adopt AD9889B HDMI/DVI Transmitter to complete T.M.D.S encoding. Adopt MC10EP89 cable driver to complete the cable driving.Mainly adopt LT3506 complete system power design.Used ATMega32 to control all the system.Finally evaluated the system output signal using a scientific testing method.