| 摘要 |
PURPOSE:To decrease the influence of a grain noise, and to improve the inspection accuracy by detecting a defect by averaging plural echo signals. CONSTITUTION:Vibrators 3a, 3b are excited by an exciting pulse which is outputted from pulsers 4a, 4b and emit an ultrasonic wave. Subsequently, the ultrasonic wave which is reflected by a defect 1a in a measuring object 1 is received almost simultaneously by two vibrators 3a, 3b and converted to an electric signal, and supplied to receivers 5a, 5b. In such a way, echo signals Sa, Sb which are obtained by output terminals of the receivers 5a, 5b are converted to digital signals by an A/D converter 6, and written in a memory 7. The echo signals Sa, Sb which are written in the memory 7 are read out and averaged by an averaging processing circuit 8, and written in the memory 7. Next, the averaged data is converted to an analog signal by a D/A converter 9, and displayed on a display device 10.
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