Design Of All-Digital Ultrasonic Flaw Detection System About Weld Ⅰ

The technology of Ultrasonic Flaw Detection is a very important method in the non-destructive examination that has been used widely in some areas, such as Industry Workpiece Detection, Medicine Ultrasonic Diagnosis. This technology mainly experiences three stages, which are Analog Ultrasonic Flaw Detection, Digital Ultrasonic Flaw Detection and Virtual Detection of Computer Software as the core. Nowadays, Digital Ultrasonic Flaw Detection technology is widely used. This thesis just uses the technology for the design of Ultrasonic Flaw Detection System about weld.Although there are many productions of ultrasonic flaw detection system about weld in home market, most of them are analog ultrasonic flaw detection devices, and wholly digital ultrasonic flaw detection devices are not very common. Even if some systems are on sale, in order to adapt different conditions and meet different cost-effective requirements, those internal structures are different. The thesis describes the pre-research system about ultrasonic flaw detection of steel pipe for corporations.Digital Ultrasonic Flaw Detection on the basis of weld mainly includes three parts: (1) Analog Unit, this section mainly implements the emission and receiving, amplitude limiting, amplification, filtering and A/D conversion of ultrasonic signal. (2) Digital Unit, this section mainly implements the processing and communication of digital signal. (3) Processing and Control of Ultrasonic Flaw Unit, this section mainly implements displaying on the computer and storage of ultrasonic flaw and so on, meanwhile, implements adjustment of parameters. The thesis mainly designs and implements the first part, which is design of FPGA module for digital ultrasonic flaw detection.In the thesis, FPGA and ARM constructs the platform of digital signal processing, in order to achieve the goal of plenty of data real-time processing, storage and transmission. This passage's mainly work of exploitation is using FPGA board DE2-70 about CycloneⅡfrom the company of ALTERA for experiment. It can achieve some functions of compression, discrimination of flaws, bottom ultrasonic flaws coupling, ultrasonic flaws in series judgment and alarming of bottom ultrasonic flaws coupling for ultrasonic data, and achieve the control of FPGA for SDRAM read and write operations, And also achieve communication between FPGA and ARM through the GPIO ports.