| 摘要 |
PURPOSE:To eliminate noise at the time of delaying response of a photodetector and rising of pulse light, and to exactly find a range, by delaying a signal which has synchronized with the pulse light, by a prescribed time, and thereafter, sampling an output signal of the photodetector. CONSTITUTION:A delaying circuit 53 delays a pulse outputted from a controlling circuit 52, by a time (t), and thereafter, sends it to an AND circuit 55. To this AND circuit 55, a pulse which is not delayed is also inputted, therefore, this circuit outputs a signal of 'H' only in a period in which two pieces of pulses of go to 'H' simultaneously and turns on a switching circuit 26. An effective signal which is brought to sampling by this switching circuit 26 is integrated by an integral capacitor 28. As soon as the photometry by a photodetector 16 is executed, the photometry by a photodetector 17 is executed, therefore, signals corresponding to the quantity of light which is made incident on these photodetectors 16, 17 are integrated, respectively, sent to an arithmetic circuit 32 and its ratio is calculated, sent to an encoder 33, encoded therein, and thereafter, sent to a decoding/latching circuit 35. |
