| 摘要 |
PURPOSE:To constitute so that a noise component is not projected to a flaw signal output shaft by providing a noise phase angle range on a phase plane of a vector scope, adjusting in advance a phase shifter so that a noise signal is always inputted to its circumference and masked, and detecting a flaw. CONSTITUTION:A Y axis direction component output 11 and an X axis direction component 12 of a flaw detecting signal are outputted from a delivery of a phase discriminating circuit 10. A phase angle psi is detected by inputting these outputs to a phase angle detecting circuit 13, and its output is inputted to phase angle comparing circuits 14, 15 and compared with an OR phase set value psi1 and psi2. In case of psi1<psi and psi2>psi, an output is generated, these output signals are made to pass through an OR circuit 16, and only when the phase angle psi exists between psi1 and psi2, an analog switch 17 is turned off. An output of this switch 17 is inputted to a flaw detection processing displaying circuit 18, and the display and processing are executed. In this way, a flaw signal can be outputted large by suppressing a noise, and a very good flaw detection is executed with a good S/N ratio. |
