| 摘要 |
PURPOSE:To simplify the constitution of an optical wave distance measuring device by delaying one of a distance and a reference signal, outputted from a photoelectric converter by turns, as prescribed and by determining its phase difference. CONSTITUTION:An optical-path switch 4 is changed over through a compound oscillator 1 to generate a distance signal arriving from a photodetector 5 and a mixer 6 via an external optical path extending from a light emitting element 2 and reflected by a corner cube 3b, etc., and a reference signal from the element 5 and mixer 6 via a prescribed internal optical path. Then, the distance signal passed through a delay circuit 7 and the reference signal arriving right after it are applied to a phase-difference measuring means 9 at the same time through a signal switch 8. Then, the means 9 makes a phase comparison between both the signals to generate a pulse with width which corresponds to the phase difference proportional to the distance, thereby controlling a gate 11 where a clock from the oscillator 1 passes. Consequently, the distance is displayed on a display device 13 via a counter 12, and an optical wave distance measuring device provided with the phase comparator of simple constitution which eliminates the need for a storage device, subtraction arithmetic part, etc., is obtained. |
