| 摘要 |
PURPOSE:To improve the photodetecting characteristic by demodulating an infrared-ray signal received by a photodetection section with the highest detection sensitivity among plural photodetection sections directed in different directions. CONSTITUTION:Photodetection sections 2, 3, 4 consist of infrared-ray photodetectors 5, 6, 7 and lenses 8, 9, 10. Amplifiers 11, 12, 13 amplify outputs of the infrared-ray photodetectors 5, 6, 7. Analog switches 14, 15, 16 are controlled for their switching by the output of AND gates 22, 23, 24 operated based on the output of comparators 16-21. Then the analog switches 14, 15, 16 are switched based on an output level of the amplifiers 11, 12, 13. Moreover, the priority with the same output level is amplifier 11 > amplifier 12 > amplifier 13. That is, the analog switch corresponding to the amplifier with the largest output level is opened. |
