| 摘要 |
PROBLEM TO BE SOLVED: To reduce cost by achieving high measurement accuracy without selecting a component used for a sensor circuit, and to reduce a trimming work of a transponder. SOLUTION: Correction data 42a based on characteristics are determined from temperature-resonance frequency measured data and pressure-resonance frequency measured data of individual temperature sensor circuit 34 and pressure sensor circuit 35, stored in a memory circuit 41 of the transponder 30, and transferred from the transponder 30 to an ECU 70 before starting tire information acquisition operation, and a tire temperature and a tire pressure are determined by using the correction data 42a during TPMS operation. A rectifying circuit 44 is provided on a correction data transmission circuit 36 of the transponder 30, and charging is performed by a carrier wave signal before starting the TPMS operation, and the correction data 42a are transmitted. COPYRIGHT: (C)2009,JPO&INPIT
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