Method of interrogation of a differential sensor of acoustic type having two resonances and device implementing the method of interrogation

摘要

A method of interrogating a surface acoustic wave differential sensor formed by two resonators is provided, wherein the method allows the measurement of a physical parameter by determination of the difference between the natural resonant frequencies of the two resonators, which difference is determined on the basis of the analysis of a signal representative of the level of a signal received as echo of an interrogation signal, for a plurality of values of a frequency of the interrogation signal in a domain of predetermined values; the analysis can be based on the cross-correlation of the said signal representative of the level according to a splitting into two distinct frequency sub-bands. An advantage is that it may be implemented in a radio-modem.

主权项

1. A method of interrogating a sensor comprising at least two resonators whose natural resonant frequency is dependent on a physical parameter using an interrogation device, the method comprising:
a step of emitting, from a radio signal generator of the interrogation device, an electromagnetic signal whose frequency is varied in a frequency band by increments of determined value, from a predetermined minimum value to a predetermined maximum value, the frequency band being split into two frequency sub-bands, each frequency sub-band containing at least the expected values respectively of each natural resonant frequency of the two resonators, a step of gathering, at an antenna of the interrogation device, a signal received as an echo from a resonator in the at least two resonators after a determined duration after the emission carried out in the emission step, for each frequency of the electromagnetic signal emitted, a step of transposing, at a mixer of the interrogation device, the signal received as the echo to low frequency by mixing with a radiofrequency signal whose frequency equals the frequency of the electromagnetic signal emitted, a filtering step, at a filter of the interrogation device, to eliminate the high frequencies of the signal mixed in the transposition step, and a step of determining, using calculation means, the difference between the respective natural resonant frequencies of the said two resonators, on the basis of the cross-correlation maximum of the characteristics constituted by the level of the signal received as the echo for each frequency sub-band as a function of the frequency of the electromagnetic signal emitted.