| 摘要 |
<p>PURPOSE:To detect a reflecting object even when multiple reflecting objects exist by using the standard sensitivity corresponding to the maximum value of received electromagnetic waves and the maximum sensitivity of an electromagnetic wave receiving means. CONSTITUTION:The output voltage of a light receiving element 5 is inputted to a variable-gain amplifier 13 after the voltage is amplified to a prescribed level through a preamplifier 11 connected to a CPU 9 through a D/A converter 15. The amplifier 13 outputs the input voltage to a comparator 17 after amplifying the voltage in accordance with a gain instructed form the CPU 9. The comparator 17 compares the output voltage V of the amplifier 13 with a prescribed voltage V0 and, when V V0, inputs a prescribed received signal to a time measuring circuit 21. The circuit 21 measures the inputting time difference between a driving signal and light receiving signal and inputs the time difference to the CPU 9 as distance data. When the maximum sensitivity of an electromagnetic wave receiving means is used, all reflecting objects existing within an extent to be detected can be detected.</p> |
