| 摘要 |
<p>PURPOSE:To maintain measuring accuracy for a long time, by providing a means for compensating the unbalance of the relative light intensities of the three-phase linearly polarized optical waves, whose polarizing angles that are inputted into a Faraday effect material are different by every 60 deg., and for compensating the change in light emitting wavelengths. CONSTITUTION:A clock CK, which is generated from a clock generator 1, drives light emitting diodes 6-8 through a shift resistor 2 and OR circuits 3-5. The generated three-phase light signals are inputted into a Faraday effect material 18 through polarizers 15, 16 and 17. The output light is projected on a photodiode 23 through an analyzer 20. The feedback circuit comprising a zero detector 27, sample/hold circuits 28-31, subtractors 32-34 and amplifiers 35-37 controls the relative values of the signal components from the diodes 6-8 at constant values. In order to compensate the change in light emitting wavelengths, a feedback circuit comprising an adder 38, an amplifier 39 and a transformer 40 keeps the sum of the current values through the diodes 6-8 constant. Thus the measuring accuracy can be maintained for a long time.</p> |
