| 摘要 |
PURPOSE:To facilitate the measurement of the beam path of a receiving echo and the detection of the peak level of an echo signal, by monitoring a plurality of threshold value levels set to the receiving signal of the echo signal over a range exceeding the max. value thereof. CONSTITUTION:Ultrasonic beam is emitted from a probe 3, and the S-wave (surface reflected wave) and F-wave (reflected wave from an internal flaw) from an article 1 to be inspected air received by the probe 3 to be sent out to a time measuring circuit 9. Next, n-pieces of counter parts 10i, 11i for the S-wave and the F-wave receive the signal from a comparator when a first signal having a threshold value level equal to or more than that from each of threshold value setting devices 12i arrives to be brought into an operative state and count the clock signal from a clock generator 16. Said counter parts receive the signal from the comparator when a second signal having a threshold value level equal to or higher than that from each threshold value setting device 12i arrives to stop the counting operation of a counter. Max. count value discrimination circuits 13, 14 for the S-wave and the F-wave respectively select max. count values and an operation circuit 15 calculates the difference value between the discrimination circuits 13, 14 to output said value after converting the same to a time value.
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