| 摘要 |
<p>The content of a counter (40) is increased by a clock signal from an oscillator (10) and the output signal of the counter (40) is supplied to the input terminal of a decoder (42). The output terminals O1-O25 of the decoder (42) are usually maintained at high levels, but, whenever the count signal supplied to the input terminal of the decoder (42) from the counter (40) increases, the terminals O1-O25 are lowered one by one in order, turning on switching circuits SW1-SW25 in order. The turned-on switching circuits SW1-SW25 output the output signals of the corresponding optical sensors and, as a result, the output signal of each optical sensor is sent to a signal processing section as a time-division multiplexed signal through a cable (44). Therefore, signals of twenty-five channels can be transmitted through the single cable (44).</p> |
