| 摘要 |
PROBLEM TO BE SOLVED: To improve precision without changing modulation signals. SOLUTION: When a distance measuring light, modulated by modulation signals F1, F2, F3 from a light-emitting element 10A, is emitted and then the reflection light is received by a light receiving element 18, distance measuring signals f1, f2, f3 and a distance measuring signal f1×n are outputted from the light-receiving element 18. When respective distance measuring signals are mixed with local signals L1×n, L1, L2, L3 by mixers 20-26; a distance measuring signal (IF signal)Δf at an intermediate frequency is outputted from respective mixers 20-26; each distance measuring signal is compared with a reference signalΔf by a computing unit 36, and the distance to a measuring point is computed, based on the phase difference among them. In this case, since the distance measuring signal (IF signal) is generated from the distance measuring signals f1, f2, f3, and the distance measuring signal (IF signal) is generated from the distance measuring signal f1×n that is a harmonic component of the distance measuring signal f1, accuracy accompanying increase in the measuring information can be improved without changing the modulation signals. COPYRIGHT: (C)2007,JPO&INPIT
|
