| 摘要 |
PURPOSE:To enable a correct discrimination whether it is a tightly contacted part or it is a detached part even when the whole measuring region of a test piece is detached, by giving a positive or negative code to the strength of a signal based upon the phase of said signal reflected from a boundary surface thereby to use the same as a measuring data. CONSTITUTION:A ultrasonic pulse generated from a ultrasonic transducer 1 is reflected at the surface of and boundary surface inside a test piece S, and received by the transducer 1. Only a reflected signal from the boundary surface which is aimed to be detected is taken out from the received signals through a gate circuit 4. After the wave of the taken-out signal is detected 5, a peak value thereof is held 6 and converted to a digital signal by an A/D converter 10. An output from the circuit 4 is, through a (+) comparator 7 and a (-) comparator 8, added to a timing detecting circuit 9. If the comparator 7 outputs earlier than the comparator 8, '1' is outputted to an image processing unit 11. In the reverse case, '0' is outputted to the image processor 11. The image processor 11 determines the rise direction of the receiving signal by the signal of the circuit 9. If it is found to be the same phase as the generated pulse, the test piece S is determined to be tightly contacted, while if it is in the opposite direction, the test piece S is determined to be separated. |
