Study On Key Technologies About Portable Ultrasonic Flaw Detector

With the increasing maturity of ultrasonic detection theory, and the rapid development of modern integrated circuits, Ultrasonic testing equipment showed amazing pace of development.Currently, digitization, miniaturization, visualization and real-time have become inevitable trends towards Ultrasonic testing equipments.In this paper, the key technologies in the process of ultrasonic inspection: ultrasonic transmission technology, data acquisition technology and denoising technology for ultrasonic echo signal are mainly studied based on the analysis of the A pulse reflection principle. All parts of the circuit design and the selection of the main components are carried out, and the applications based on EVC4.0 under the Windows CE.NET system is designed, so as to achieve the functions of ultrasonic flaw detection system. The main works of this paper are as follows.Firstly, according to the characteristics of ultrasonic transmitter circuit, the relationship between excitation pulse and transmitting pulse is researched, and the way of incentives for the system is choosed. Meanwhile, in order to improve the incentive effect of the transducer, the original circuit is improved and the accuracy of the circuits is verified by using the circuit simulation.Secondly, by analyzing the data collection techniques of ultrasonic echo signal, limiter circuit, variable gain amplifier circuit, filter circuit, A/D acquisition and data buffer circuit is designed to meet the requirement of high-speed and real-time features. DMA technique is also used to bring about the fast data transmission.In addition, the ultrasonic echo signal can be inevitably affected by the large number of the noise signal in the process of collection and transmission, So in this paper, wavelet analysis techniques is used to realize the processing of signal denoising, and extract the original signal effectively. And through the appropriate application, wavelet analysis technique proves to play a good denoising effect.Finally, through the application interface design, the graphics of ultrasonic echo data is displayed, the defect is determined, and the function of storage and playback to the testing data is achieved.