Time-division, time-division and frequency division, time-division and code-division, time-division and code-division and frequency-division combined surface acoustic wave tag temperature measurement system and method

Abstract

The invention discloses four surface acoustic wave label temperature measuring systems and corresponding temperature measuring methods. Based on the combination of tie division, time division-frequency division, time division-code division, and time division-code division-frequency division, the multi-node anti-collision temperature measurement is realized. The temperature measuring system is composed of a surface acoustic wave label node, a reader and a server. During the time-division method, different positions of echo pulses are divided into a plurality of surface acoustic wave label nodesaccording to different positions of the reflection gratings of labels. During the time division-frequency division method, time division labels are classified according to different resonance frequencies. During the time division-code division method, time division labels are grouped according to different phase codes of a phase modulation interdigital transducer. During the time division-code division-frequency division-combined method, time division labels are classified firstly and then are grouped. For the temperature measuring systems of different temperature measuring methods, the reader sends out different excitation signals. According to the invention, the ISM and the bandwidth allowed in the national standard are satisfied, and the number of nodes is increased. The verification function is achieved, and the anti-jamming capability is high. The real-time performance is relatively good.

Description

Technical field: [0001] The invention relates to a surface acoustic wave label temperature measurement system and method combining time division, time division and frequency division, time division and code division, time division and code division and frequency division, and belongs to the field of wireless sensing and radio frequency identification. Background technique: [0002] Surface acoustic wave devices can be used as sensors, which can be divided into two types: resonator type and delay line type, respectively, as figure 1 and figure 2 shown. The resonator-type surface acoustic wave device is composed of a piezoelectric substrate, an interdigital transducer, and a reflective grating. The reflective gratings at both ends of the interdigital transducer are arranged in a dense array to form an acoustic resonant cavity. The delay line surface acoustic wave device consists of a piezoelectric substrate, an input interdigital transducer, and an output interdigital trans...

AI Technical Summary

Problems solved by technology

[0008] (3) For the resonator-type surface acoustic wave sensor, only a single characteristic quantity of the resonant frequency can be extracted from the echo signal, and there is no other check code, so the reliability of the temperature measurement result cannot be guaranteed

[0009] (4) The passive wireless detection system may fail when there is strong electromagnetic interference, resulting in abnormal detection results

However, the current resonator-type surface acoustic wave temperature measurement system cannot judge the abnormality of the system based on the detection results and repair the system

[0010] (5) When the frequency division multiple access method is used to poll each resonator-type surface acoustic wave sensor node for temperature measurement, if the number of nodes increases, the polling time will become longer, thus affecting the real-time performance of temperature measurement

The above two methods of improving temperature measurement accuracy need to sacrifice time, that is, further affect the real-time performance of temperature measurement.

Images