| 摘要 |
PURPOSE:To measure highly sensitive and highly accurate angular velocity with proper temperature characteristics by reducing the optical intensity at the center part of interference stripes based upon a phase difference generated by angular velocity so as to return by one period when the change of the optical intensity is more than one period, and detecting a frequency difference. CONSTITUTION:Light projected from a light source 11 is divided into two components by a distributer/coupler 13 and the respective light components are made incident to an optical path 22 through ultrasonic transducers 16, 24 as right-handed revolution light and left-handed revolution light, projected from end surfaces 22b, 22a, interfere each other through the coupler 13, and then made incident to a photodetector 27. The output of the photodetector 27 is inputted to a subtractor 38 through lock-in amplifier 34, a VCO35 and a frequency meter 37 to find the difference between the output and the frequency fs of a setter 38 and the difference is inputted to a subtractor 42 to find the difference between the difference value and the frequency difference between the right-handed revolution light and left-handed revolution light of a setter 41. The difference output from the subtractor 42 is applied to a switch 47 and positive and negative voltage generating circuits 45, 46 are switched so that the phase difference between the right-handed revolution light and left-handed revolution light is made 2pi or less through an analog adder 44, the VCO35 and the transducer 24. Thus, highly sensitive and highly accurate angular acceleration can be measured. |
