| 摘要 |
PURPOSE:To improve the S/N and to detect a defect with high accuracy, by averaging the position signals of a transducer to obtain a mean position signal and adding and averaging the echo signals corresponding to the position signals in a synchronous way in terms of time. CONSTITUTION:An ultrasonic transducer 11 is excited by a pulse oscillator 12 to transmit an ultrasonic pulse into a metallic material 6. Thus the echos reflected from a defect 8, a welded wire 7 and the bottom surface 9 are received in the form of a defect echo R or a pseudo echo P to be stored in a memory 16. At the same time, the position of the transducer 11 is detected by a position detector 15, and both the position signal Xi and echo signal Ri are stored in the memory 16 in correspondence to each other and in according to the shift of the transducer 11. Then n units of signals Xi and Ri are sent to an arithmetic circuit 17 by the timing signal of a synchronous circuit 13. Based on the arithmetic result, the position and the size of the defect 8 are displayed to a display device 18. |
