Rapid search method of resonant frequency of surface acoustic wave resonator (SAWR)

Abstract

The invention relates to a rapid search method of a resonant frequency of a surface acoustic wave resonator (SAWR). Excitation signals synthesized by fixed low-frequency signals and size-adjustable local oscillator signals are emitted for exciting the SAWR; then whether received signals are effective excitation signal of the SAWR is determined, if not, the excitation signals are adjusted for performing excitation again, and if so, down-conversion processing is performed, and a period of echo signals is obtained and stored through searching for signal zero-crossing points; and finally, a maximum value of the period of the echo signals corresponding to all effective excitation is sought, excitation signals corresponding to maximum period signals are obtained, frequency estimation is performed on the echo signals generated when the excitation signals act on the resonator, and a current resonant frequency estimation value of the SAWR is obtained. According to the invention, the algorithm does not need frequency estimation in a scanning process, the whole scanning process is completed in a time domain, signal phase influences are eliminated, the scanning speed of the SAWR is effectively accelerated, and the demodulation speed of an SAW sensor is improved.

Description

technical field [0001] The invention relates to a signal detection technology, in particular to a fast search method for the resonant frequency of a surface acoustic wave resonator. Background technique [0002] In the reading process of the reader, frequency division multiplexing is used to distinguish each resonator, but how to quickly search each resonator is a difficult point. Currently commonly used surface acoustic wave resonator SAWR scanning methods can be divided into two: one of which scans the working bandwidth of each resonator by setting a step size, but this process takes a long time; the other method is to use IQ The demodulation algorithm is used to realize the rapid approximation of the frequency of the resonator, that is, to collect two signals with a phase difference of π / 2, and to find the phase angle corresponding to the maximum spectral line through Fourier transform to determine the adjustment direction of the frequency of the excitation signal, and fi...

AI Technical Summary

Problems solved by technology

[0003] The present invention aims at the problems of slow scanning speed, complex scanning process and easy influence by signal noise of the existing surface acoustic wave resonator, and proposes a fast search method for the resonant frequency of the surface acoustic wave resonator, using the period of the excitation signal and the echo signal The relationship between the surface acoustic wave resonator is quickly scanned to realize the fast search of the resonant frequency of the surface acoustic wave resonator

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