| 摘要 |
PURPOSE:To attain ease of measurement of a communication zone by providing the 1st and 2nd timer means and counting the pulse number outputted from a speed detecting means while one of them is in operation. CONSTITUTION:A polling signal outputted from a transceiver 1 is detected by a detection circuit 13 and a comparator 14. A car speed pulse proportional to a moving speed of a car is counted by a counter 17 while either the 1st timer means comprising a monostable multivibrator 15 operated for a period longer than a signal transmission period through the detection of the presence of the polling signal or the timer means comprising a monostable multivibrator 16 operated for a pause period through the detection of the absence of the polling signal is activated. The moving distance of the car is operated based on the count value of the counter 17 and the result of operation is displayed on a display 19 to measure the communication zone. |
