| 摘要 |
PURPOSE:To provide the title optical mode sensor circuit for increasing S/N by a method wherein the detection noise component due to minor fluctuation in luminescence level is removed to control the light source level otherwise the components excluding the detection signal component are decreased and so forth. CONSTITUTION:The title optical mode sensor circuit is composed of a light source 11 emitting light to an optical fiber sensor 14, a photo detector 4 detecting optical signals from the optical fiber sensor 14 so as to output electrical signals, a photo detecting amplifier 5 amplifying the electrical signals, a reference voltage generator 6, a comparator 7 comparing the photo detecting amplifier 5 output with the reference voltage and a band eliminator 9 removing the detected frequency component provided between a light source driving level controller 8 transmitting the voltage signals to nullify the output from the comparator 7 and a light source driving part 10. |
