| 摘要 |
<p>PURPOSE:To accurately detect physical quantity from the output of an optical sensor at a high speed without providing a DC filter, by converting a luminous intensity modulation signal to a digital signal and calculating DC and AC components on the basis of the average value for one cycle period of said signal. CONSTITUTION:The light from a light emitting element 1 is inputted to a light modulation part 11 consisting of a polarizer 3, a Faraday element 4 being a light modulation element 4 and a detector 5 through an optical fiber 2. The output of said modulation part 11 is inputted to a photodetector 7 through an optical fiber 6 to be converted to an electric signal and the output thereof is inputted to an A/D converter 13 through a sample holding circuit 12 to be converted to a digital signal. This signal is inputted to an operator 14 to calculate DC and AC components on the basis of the average value for one cycle period of a luminous flux modulation signal and the AC component is divided by the DC component to calculate physical quantity. By this method, physical quantity can be accurately detected at a high speed without using a DC filter.</p> |
