| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor laser digital vibration measuring device reduced in size and weight as the whole device by simplifying an optical system and a signal processing system. SOLUTION: This laser vibrometer comprises a semiconductor laser having a fixed laser oscillating frequency; an optical head part having an optical element (LE) 2 arranged so as to emit the emitted light of a semiconductor laser diode (LD) 1 to the surface of a measuring object 3 and couple a part of the reflected light with the semiconductor laser as a return light and a light receiving element (PD) 4 for detecting a change in output of the semiconductor laser caused in relation to a vibration displacement of the measuring object 3; a circuit (A) 7 having the function of supplying a current to the semiconductor laser in addition to the function of amplifying a signal component from the output of the light receiving element; an AD converter 18 for AD-converting the output of the amplifying part; and a circuit (B) 11 having the function of counting the number of Doppler beat waves, the direction determination function of determining the displacement direction from the output of the amplifying part and fetching a signal for switching the addition and subtraction of the counter part, and the function of storing the counted value of the counter part to compute the vibration displacement. COPYRIGHT: (C)2004,JPO&NCIPI
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