Design And Analysis Of Transceiver System Of SAW Sensor In TPMS

TPMS is a kind of system which used for real-time tire pressure and temperature measurement, as well as alerting low tire pressure caused by leak or high temperature and high pressure to improve vehicle safety performance. Passive TPMS is a promising, and inevitable tendency of development, but its transceiver was seldom reported. This thesis use new passive temperature and pressure sensors based on SAW to design a TPMS transceiver and it includes the following areas.Firstly, according to the character of the passive SAW sensor, when receiving the query pulse it will return three pulse signals, and the difference of the signals'time contain the information of temperature and pressure. As the difference of the times is too hard to measure with hardware, this article uses the phase difference to measure time difference indirectly. We uses indirect comparison method, Let the three return signals contrast with the same frequency signal phase, we can get their phase differences, as well as the information of the temperature and pressure.Secondly, according to the phase measuring principle, design hardware system. The system mainly consists of three basic modules: RF modules, data acquisition and storage module and low-speed devices management module. RF module mainly produce RF signal, receive returns and phase measurement. Data acquisition and storage module's function include controling the width of the RF signal interception, controling the timing of data collection, data acquisition and storage. Low-speed devices management module is primarily used for system initialization control, information displays and reservation interface, etc.Finally, the modularization software was designed according to the hardware. And test the important parts to ensure its reliability. In order to facilitate data analyses using serial port communication upload data to PC .Using Matlab to display the data in a graphical way.This paper complets the main content of the TPMS, which contains the theory design and realization, and then demonstrats the feasibility of theory design which the passive SAW sensor transceiver is based on.