| 摘要 |
PROBLEM TO BE SOLVED: To suppress saturation of a light receiving signal even if the input intensity of light is excessive.SOLUTION: A laser radar 1 projects a laser beam from a light projection section 3, receives reflected light from a measuring object 50 with a light receiving circuit 10, converts the light into an electric signal, and measures the position of the measuring object 50 on the basis of the signal. The light receiving circuit 10 comprises: a light receiving element 5; amplification circuits 7 and 8 for amplifying an output signal from the light receiving element 5; a variable impedance circuit 9 for attenuating an input signal from the light receiving element 5 to the amplification circuits 7 and 8; and a light receiving control section 12 for performing a predetermined control on the basis of a light receiving signal output from the variable gain amplification circuit 8. When the light receiving control section 12 determines that the light receiving signal is in a low-level saturation state, it adjusts the gain of the variable gain amplification circuit 8 so that it becomes small. When the light receiving control section 12 determines that light receiving signal is in a high-level saturation state, the input signal from the light receiving element 5 to the current voltage amplification circuit 7 is attenuated by the variable impedance circuit 9. |
