| 摘要 |
PROBLEM TO BE SOLVED: To reduce the quantity of installed initiators without increasing a cost.SOLUTION: In a tire monitoring device 14, when the receiving intensity of a request signal 17 exceeds a response threshold y, a sensor unit 15 transmits a response signal including specific ID information, and then comes into a sleep state. One initiator 18 is provided for the sensor unit 15. The sensor unit 15 is configured so that timings at which the receiving intensity exceeds the response threshold y are displaced from each other by receiving the request signal 17 from the initiator 18 with different receiving intensities. The initiator 18 is a variable output initiator capable of changing the transmission intensity of the request signal 17. Since a controller 22 makes the variable output initiator change the transmission intensity of the request signal 17, the response signal is transmitted in order starting at the sensor unit 15 at which the response threshold y is earlier exceeded. |
