| 摘要 |
<p>PURPOSE: To generate a period alarm in also a low speed area by setting alarms so that the alarm levels may be different for plural thresholds and inhibiting the transmissions of the alarms when the output value of a speed sensor is except the threshold of the smallest value when the value is below a set value. CONSTITUTION: A measuring means is composed of an antenna 1, the transmission circuit 2 provided with an oscillator 2a and an adjustable circuit 2b adjusting transmission power, a reception circuit 3 and a control circuit 4. Further, the control circuit 4 is provided with an automatic adjusting means 4a automatically adjusting the adjustable circuit 2b so as to increase transmission power when the speed is high according to the output from a speed sensor 5 and so as to decrease transmission power when speed is low and an arithmetic means 4b calculating the distance from the vehicle running in the forward direction and the change. Further, the circuit 4 is provided with an alarm transmission inhibition means 4c inhibiting the transmissions of alarms for the threshold except the threshold which is set to the smallest value of the plural thresholds, when the output value of the speed sensor 5 is below set speed.</p> |
