Method and system for improving detection accuracy of delay line surface acoustic wave (Surface Acoustic Wave) sensor

Abstract

The invention discloses a method and a system for improving the detection accuracy of a delay line surface acoustic wave (Surface Acoustic Wave) sensor and relates to a detection method and a detection system of the SAW sensor. The method for improving the detection accuracy of the delay line SAW sensor comprises the following steps of: 1, firstly searching a corresponding relation that delay time and a phase are changed with a measured temperature; 2, then establishing a corresponding relation between the measured temperature and a delay time difference as well as a phase difference; 3, and finally obtaining a corresponding relation between the phase difference and the measured temperature. In the invention, the demodulation of delay time measurement and the demodulation of phase measurement are combined; the advantage of accurate demodulation of the phase is essentially utilized; the demodulation process has small calculated amount; the method and the system are convenient to implement in an FPGA (Field Programmable Gate Array); the demodulation accuracy is improved; the problem of phase ambiguity in the phase demodulation process of the delay line SAW sensor is solved; and by utilizing the method, the effects that the temperature detection accuracy can reach 0.05 DEG C and the temperature detection range is at least in the range of 0 DEG C to 50 DEG C are realized, so the problem of phase ambiguity really can be solved by combining the delay time measurement and the phase measurement to carry out demodulation.

Description

technical field [0001] The invention relates to a SAW sensor detection method and system, in particular to a method for improving the detection accuracy of a delay line surface acoustic wave sensor. Background technique [0002] At present, due to the simple structure, small size, light weight, good stability, wireless connection, no power drive and high sensitivity of the surface acoustic wave sensor, it can be used in a variety of complex and harsh environments. Since the 1980s, the United States, Germany, Japan and other countries have carried out extensive research on surface acoustic wave wireless passive sensors. In published patents and technical documents, various methods of using surface acoustic wave devices to realize wireless passive sensors have been reported. The surface acoustic wave sensor adopts surface acoustic wave sensing technology to obtain working energy directly from the radio frequency signal, without the need to integrate a power drive circuit, the ...

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Problems solved by technology

Du Feng and others only mentioned the phase offset of phase demodulation, but did not discuss the phase ambiguity

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