| 摘要 |
PURPOSE:To make a measurement error based upon a measured distance constant by emitting a light pulse and driving the next light pulse by its reflected light, counting pulse trains and a pulse train of high frequency between the pulse trains, and calculating the distance. CONSTITUTION:A driving circuit 1 drives a light emitting element 14 and a target 3 is irradiated with light from the element 14 through a half-mirror 2 to guide its reflected light to a photodetector 4 through said half-mirror 2. The output of the detector 4 is sent out in the form of a pulse waveform to an amplifier 5 and a waveform shaping circuit 6. A high-precision timer 7 is operated for a constant time under the control of a control circuit 11. The counter 8 counts driving pulses of the element 14 and an oscillator 9 oscillates only during the operation of the timer 7 at a frequency higher than the frequency of the pulse train generated by the circuit 1. A counter 10 counts the pulses from the oscillator 9. The counted values of the counters 8 and 10 are stored in a memory 12 and a CPU13 calculates the distance. Thus, the measurement error based upon the measured distance is made constant. |
