| 摘要 |
PURPOSE:To eliminate errors in the gain and frequency characteristics between channels, to decrease the number of parts, and to obtain a high-precision distance measurement signal by switching one variable gain amplifier through switching operation based upon a distance measurement timing signal. CONSTITUTION:Switch circuits 10a-10c turn on and off photodetecting circuits 5a and 5b and a gain control circuit 7 according to the timing output of a level decision circuit 9. Irradiation light from a light emitting element 2 is reflected by a body 3 to enter photodetecting elements 4a and 4b. Their photodetection outputs are led in the variable gain amplifier 6 through the photodetecting circuits 5a and 5b in operation states and amplified with the gain corresponding to the output of a control circuit 7, and both amplification outputs are supplied to a waveform processing circuit 8. The processing circuit 8 processes both amplification levels to output final distance information. |
