| 摘要 |
PURPOSE:To realize a communication system which reduces the installation cost of devices and also facilitates the maintenance and repair of facilities by performing vehicle sensing by a vehicle sensing circuit and communication between a ground equipment and a vehicle equipment alternately at specified intervals through the operation of a switching circuit part. CONSTITUTION:A ground equipment is equipped with an oscillating circuit 10 connected to a loop coil 2 laid on a road surface, vehicle sensing circuits 12-17 for detecting variation in the frequency of the oscillating circuit 10 due to arrival of a vehicle, and transmitting and receiving circuit parts 19-15 which perform vehicle communication with the vehicle equipment through the loop coil 2. Further, switching circuit parts 11, 18, 26, and 27 switch and connect the oscillating circuit 10 and transmitting and receiving circuit parts 19-25 to the loop coil 2 alternately at specified intervals. The vehicle, on the other hand, is equipped with an antenna 6, and the vehicle equipment including transmitting and receiving circuits 31-39 which perform communication with said ground equipment through the antenna 6. Through the operation of said switching circuit parts, vehicle sensing by the vehicle sensing circuits and communication with the vehicle equipment are performed alternately at specified intervals. |
