Design, Data Acquisition And Storage System Based On Traffic Detection

Vehicle flow detector is with vast application prospect while used as one of the traffic detecting methods. To develop the vehicle flow detector, lots of outfield experiments are requried to set up the characteristic database of the vehicle infomation so as to improve the target recognition algorithm. Based on the vehicle flow decetor, a data acquisition and storage system is designed and realized in this paper.In this system, FPGA is adopted as the master controller, which stores the A/D data into the FLASH storage module via FIFO. The host computer can read data stored in FLASH through USB interface for wave replay and following analysis. In this paper, the difference frequency signal characteristic of the vehicle flow detector is briefly analyzed, the system index is established, and the software and hardware are designed. Firstly in hardware, circuit for each module is concretely introduced, of which ping-pang structure is adopted when FIFO receiving A/D data to avoid data loss, bit extension and cyclic operation technique are used in FLASH to improve operation speed, and USB control chip FX2 works in asynchronous Slave FIFO mode. Secondly in software, program of each module in FPGA is presented, firmware design of asynchronous Slave FIFO mode and application program for host computer is discussed in detail. Finnaly, error of ADC is analyzed, problems and solutions in circuit debugging are briefly described, and system performance is tested.The resolution of this data acquisition and storage system is 12bit, acquisition rate is 2.5MSPS, storage capacity on board is 32Gbit, and offline mode is supported. The communication with host computer is through USB2.0 interface, and could obtain a transmission rate higher than 14MB/s, reaching expected index and function.