| 摘要 |
PROBLEM TO BE SOLVED: To inhibit higher harmonic components of a reference signal from being superposed as a noise on the distance measuring light. SOLUTION: The reference signal (50MHz) generated by the reference signal generater 12 is divided into 1/2 by the divider 14, the signal is 3 multiplied by the multiplier 18, the light emitted by the light emitting device 26 is modulated with the 3 multiplied reference signal as a modulation signal, projected toward a target as a distance measuring light, the distance measurement signal f1 is extracted by the band pass filter 38 from the distance measurement signal f0 obtained by the light receiving element 30 for receiving the reflected light from the target, the distance measuring signal f1 is converted into the distance measuring signal of intermediate frequency through the mixer 44 and the low pass filter 56, the distance measuring signal IF1 is converted into digital data by sampling with the A/D converter 68, the phase difference between the reference signal and the distance measuring signal IF1 is obtained based on the digital data by the operator 74, and based on the phase difference, the distance to the measurement objective point is obtained. COPYRIGHT: (C)2007,JPO&INPIT
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