Ultrasonic Testing System Based On PCI Express Bus High-speed Data Acquisition Card Design

At present,ultrasonic nondestructive testing technology has a wide range of applications on detecting whether key parts of high speed train have dangerous fatigue damageor crack.Due to a series of shortcomingsof analog ultrasonic detectionsystem,such as low accurary ? big error and data without being stored,it can not meet actual demand.Besides,digital ultrasonic inspection system has a low sampling rate on the market at present and is only used in low frequency band of the ultrasonic signal detection.And it can not guarantee accuracy.AS the FPGA(Field Programmable Gate Array)technology applied in the field of high speed signal processing,digital ultrasonic flaw detection system with high veracity and automation has a bright future.The thesis designed a kind of high speed data acquisition card based on the PCI Express bus.The high speed data acquisition card can be used to collection ultrasionic backward-wave signal,and provides a hardware platform support for locomotive ultrasonic flaw detection system research.Firstly,this paper simply introduced the principle of ultrasonic flaw detection.Then,thepaperanalyzed the most key technologies of influencing the properties of high speed data acquisition,including acquisition,caching and transmission.At last,using the high-speed ADC chip AD9218 of the ADI(Analog Devices)captured the ultrasionic backward-wave signal;Using the third generation cache technology DDR3 SDRAMrealized datacache;Using FIR filter handled the signal;Using the PCI Express high-speed serial bus transmitted data to Host memory of the PC.The logic design of the whole system was finished in hardware description language(Verilog HDL)on FPGA.The Xilinx Virtex-6 series FPGA with DDR3 SDRAM Memory interface and the Logi Core Endpoint Block Pluswas used.Combined with PCI Express bus deriver,successfully implementing that acquisition signalswastransmitted to the host memory by DMA of PCI Express bus.At theend of thesisfirstly tested the performance of PCI Express DMA writing/reading and modes of interruptand gave the different DMA reading/writeing rating values under the diffenent transfer size.Atlast,tested the whole system.The result verified stability and accuracy of the whole system,and meeted demand of ultrasonic echo signal collection.