| 摘要 |
<p>PURPOSE: To set the accurate sensitivity by synchronously deciding the length of a measuring synchronization, comparing it with a reference value, and outputting a signal indicating the presence of a vehicle when the difference of the both is larger than a threshold value. CONSTITUTION: The 'frame section' of a 'measuring frame' having larger measuring period is constituted. Each time the frame section is completed, the final count from a synchronous counter 38 is combined with the number induced from the final count generated during previous frame section to form one measured value. Then, it is compared with a reference value, and if it largely exceeds the reference value, the presence of one vehicle is indicated. A processor 20 gives a suitable output signal to a suitable primary and auxiliary output circuits. Thus, accurate sensitivity can be set.</p> |
