Design Of Delayed Linear SAW Temperature Sensor Measurement Transceiver System

Temperature detection is one of the research hotspots in industrial production and other industries in recent years,but many commonly used temperature measurement systems have their own defects and cannot meet the actual and ever-changing needs.For example,measuring the temperature of a high-speed rotor,good sealing conditions,or temperature in a difficult installation environment requires temperature sensors to transmit temperature information under wireless conditions.At present,domestic research on the surface acoustic wave temperature sensor has made great progress,but the measurement system matched with the sensor has rarely been reported.This paper is mainly for the new wireless passive SAW temperature sensor supporting measurement system,the main research contents are as follows:Firstly,the working principle of the wireless passive SAW temperature sensor is studied.The sensor is excited by the pulse inquiry signal,and the pulse signal reflected by each reflector is returned after the sensor is excited.In this paper,the phase difference of the return pulse signals of each reflector inside the sensor is measured,and the temperature of the sensor is estimated by the phase difference.The measurement scheme is given according to the principle of the sensor.Second,design the system hardware according to the phase measurement principle.The system hardware mainly consists of an RF signal generation module,a transmission channel module,a signal conversion acquisition module,a controller module,a display module and a system power module.The function of the RF signal generation module is mainly to let the system hardware generate a 429.2MHz pulse query signal to wirelessly excite the SAW temperature sensor.The main function of the transmission channel module and the signal conversion acquisition module is to receive the signal returned by the energy-efficient sensor,perform IQ quadrature phase demodulation on the signal returned by the sensor,and convert the phase value represented by the analog voltage form into a digital quantity.The function of the controller module and the display module module is to use the FPGA to process thecollected signals of I and Q signals,calculate the temperature value,and send the temperature value to the display screen for real-time display.Then,modular software corresponding to hardware is designed.The system software mainly includes: RF switch control module program,dual AD data acquisition and storage module program,data processing module program,serial communication module program.The simulation software ModelSim and the debugging software SignalTap II are used to simulate and debug each module program,which verifies the correctness of the functions of each software module.Finally,test the hardware modules of the system and perform constant temperature and heating tests on the entire measurement system.The test results show that the temperature measurement system designed in this paper has a temperature range of 25?-130?,the measurement error is ?6.0 ?,the temperature measurement period is 0.33 seconds,and the wireless signal transmission distance between the measurement system and the SAW temperature sensor is 10 cm.