| 摘要 |
PURPOSE:To precisely detect a distance over multiple points in a wide dynamic range by forming a running control signal of a detected optical pulse signal that is subjected to amplitude modulation at the max. light receiving sensitivity in a digital manner. CONSTITUTION:The current in a light emission diode D mounted on a preceding car is an intermittent pulse in a frequency F2 and a cycle t. Because the its amplitude value becomes smaller in order by resistances of R1<R2<R3, its sending light comes to a seris of intermittent lights of the first- the third waves smaller in amplitude in order. In the receiving circuit of a following car 2, when the distance between the cars is enough, the receiving output Es< reference voltage Er is satisfied, and the output Ec of a comparator is zero. If the distance is reduced, the first wave of the sending light exceeds the Er and a pulse is generated in the Ec. That it to say, the Ec corresponds to the distance between the cars. With generation of the pulse (a), a decoder 28 outputs to a sending terminal Q11, with detection of the third wave, to terminals Q11 and Q12, with detection of the third wave, outputs to all the terminals. With this process, a speed is controlled in correspondence to the distance between the cars. |
