| 摘要 |
PURPOSE:To reduce the area of an IC chip by miniaturizing a circuit, by changing over signals of two light receiving means receiving light from a distance measuring object and supplying one of them to a signal processing means to process the same in time sharing. CONSTITUTION:An analogue switch circuit 5 is connected between the head amplifiers 3, 4 of silicon photodiodes 1, 2 and a signal processing system comprising an AC amplifying cirkcuit 6 and a DC amplifying circuit 9, and the predetermined clock pulse of a sequence control circuit 13 is supplied to a synchronous detection circuit 8, a gain control circuit 12 and the drive amplifier 14 of an infrared ray emitting diode 15. At first, the signal of the diode 1 is amplified up to a prescribed level by the circuit 6 to be held and amplified around the fundamental wave component of the light of the diode 5 by a band filter amplifier 7 while the amplified signal is held by a CH1 signal hold circuit 10 among CH1 and CH2 signal hold circuits 10, 11 through the circuits 8, 9 and the signal of the diode 12 is held in the similar way by the circuit 11 to be processed. |
