Design Of Data Transmission System For High Frame Frequency CMOS Cameras

In modern airborne fire control system of the aviation, technique of hud image is applied to achieve integrated display of the airplane control parameters, radar, navigation instruments, various parameters and video information in weapon system.This technique greatly increases the display capacity of data information. A high speed transmission system was designed based on a high frame frequency CMOS camera used in a battleplane to record the video data of the flight instrument, monitor image and transmission condition of missiles outside the cabin.The research background and current situation of data transmission system for high frame frequency CMOS cameras was introduced. The system was divided into three modules as high frame frequency CMOS imaging module, FPGA controlling module and PHY. The research emphasis was the design of FPGA controlling module and PHY module.CMOS image sensor chip LUPA-300, produced by Cypress corporation, was applied in high frame frequency CMOS imaging module.The sensor and its peripheral circuit design were introduced. The CMOS imaging module converses the image data to digital signals and sends to FPGA through SPI interface.The research emphasis focused on the realization of FPGA controlling module.The design of FPGA controlling module included the programming and realization of GMAC(Gigabit Media Access Control) core in Verilog HDL(Hardware Description Language). GMAC was designed based on IEEE 802.3 protocol, and the core can work in half duplex and full duplex mode with transmission rate of 1000Mb/s,and it supplies WISHBONE bus and GMII(Gigabit Media Independent Interface). The Verilog GMAC core was synthesized in the ISE10.1 design environment of XILINX FPGA and simulated in Modelsim6.5.Peripheral circuit of PHY was accomplished. The PHY chip BCM5461S of BROADCOM corporation was selected in system design. The chip contains GMII and can accomplish 1000Mb/s transmission of high frame frequency image information combined with GMAC. Experimental test was implemented.When the high frame frequency CMOS camera works with a resolution of 640×480 and a 250f/s acquisition speed, the data transmission rate of the system can reach up to 1000Mb/s. Experimental results show that this high speed transmission system has some advantages such as stability and reliability, real-time performance and flexibility.