| 摘要 |
PURPOSE:To achieve highly accurate detection of changes in the shape of the surface of a sample by checking the variation of a phase with an ultrasonic flaw detector. CONSTITUTION:This apparatus is provided with a probe 1, a voltage control type oscillator 2A, frequency dividing circuits A3 and B4, an RF switch 5, an amplifier 6, an multiplier 7, a circulator 8, a lowpass filter 9, an A/D converter 10, an arithmetic device 11A, a positioning device 12, an input device 13 and a D/A converter 14. The variation of a phase is detected by a phase difference computed at two or more of frequencies thereby enabling the eliminating of discontinuity of the variation of the phase along with hither resolutions. |
