Measuring apparatus

Abstract

Abstract PURPOSE:To obtain a more correct measured value free from the effect of fluctuation in refractive index, by enabling a reduction in the fluctuation of refractive index in air while a fluctuation component alone of a laser interferometer is allowed to be monitored. CONSTITUTION:A temperature-stabilized air is sent at almost a uniform speed to laser beams 4X and 4Y reciprocating with respect to mobile mirrors MX and MY from a fan FN to reduce fluctuation in measurement with inteferometers 5X and 5Y. Moreover, a relationship between an optical system and the direction of wind is so set that windward and lee parts of the beams 4X and 4Y are always the same with respect to the direction of wind to always cause hourly changes in the fluctuation of outputs of the interferometers 5X and 5Y from the windward to lee side. Thus, as a hourly rate of change in measure values can be found immediately and wind speed is almost constant, a fluctuation component alone of measured values of the inteferometers 5X and 5Y can be measured without time delay. Change in the fluctuation is compensated for by the correction of the measured values by the size of the fluctuation component.

Inventors

• 👤 Shoichi Tanimoto

Bibliographic Details