| 摘要 |
Device for measuring a physical quantity, the changes of which produce changes in the lengths of the light path through optical wave-guides used as measuring elements, either directly or indirectly via measurement-quantity transducers, comprising a light source, means for dividing a light wave supplied by this light source into two light waves, for guiding at least one of the two light waves through an optical wave guide used as measuring element, for shifting the phase of at least one of the two light waves and for recombining the two light waves after passing through the optical wave guides used as measuring elements and the phase-shifting means, a detector for determining the intensity of the total light wave resulting from the recombination, evaluation means (11-17) for evaluating the detector output signal and control means (18, 20-31), controlled by these means, for controlling the phase-shifting means and output means (19) for outputting the measurement value of the physical quantity, the evaluation means (11-17) comprising means (12-15) for forming at least two controlled variables depending in different manner on the phase shifts, and means (16, 17) for mathematically processing the controlled variables and for obtaining a control signal for controlling the control means (18, 20-31) from the processing result. <IMAGE> |
