Phase Extraction Algorithm Research For Delay-line SAW Sensor

Surface Acoustic Wave (SAW) sensor has many advantages, such as small size,high reliability, immunity to electromagnetic interference and passive wirelesscommunication, so it is widespread concern. SAW sensor could be divided into twokinds: SAW sensor based on delay line and SAW sensor based on resonator. This thesisresearchs on SAW sensor based on delay line, and mainly does echo signal phaseacquisition algorithm of SAW sensor based on delay line: this paper compares differentphase extraction algorithm through the establishment of the echo signal model, andachieves phase measurement of echo signal of SAW sensor based on delay line usingapFFT method.Firstly, this paper analyses the main structure and the basic principles of measuringtemperature of SAW temperature sensor based on delay line. Theoretical analysisindicates that the precise extraction of phase information of echo signal contributes tohigh-precision measurement of temperature.Secondly, this article introduces several common phase measurement methods, andthe analysis of its own advantages and disadvantages, a theoretical study on phasemeasurement method, the all-phase FFT phase measurement method, the pre-processingof all-phase FFT algorithm and the corresponding flowcharts.Furthermore, a baseband signal and RF echo signal model is established andsimulated through the theoretical analysis and the characteristic analysis of echo signalof SAW sensor based on delay line. Phase extraction algorithms are put forwardcorresponding to this project. The MATLAB simulation is used to analyze eachalgorithm based on the echo signal models, comparing the precision and anti-noiseperformance of all these various phase measurement methods. Results indicate that theimproved algorithm for phase measurement, in terms of accuracy and noiseperformance, has been improved.Finally, this paper talks about the construction of SAW sensor system based ondelay line for temperature measurement, the introduction of sensor experimental systemand key technologies. The verification is obtained via experimenting on the echo signalphase acquisition algorithms, and uses the experimental system for temperaturemeasuring, which basically proves that the sensor based on tests coincide to the resultsof theoretic data analysis. Experimental results indicate that this phase acquisition algorithm can be applied to obtain high accuracy temperature data, and the validity ofthe proposed algorithm is verified.To sum up, this paper proposes the improved method of phase measurementthrough the creation of echo signal model of SAW sensor based on delay-line andsimulation analysis. The high-accuracy measurement of temperature is realized and thereliability of experimental data is analyzed based on this algorithm in the finalexperiment. These related results have important significance for the practical use ofSAW sensor based on delay line.