一种声表面波转矩传感器快速解调方法设计

Designing of a Fast Demodulation Method for Surface Acoustic Wave Torque Sensor

针对多个谐振器组成的无线无源声表面波(SAW)转矩传感器阅读过程复杂、耗时长的问题,利用SAW谐振器的频率响应特性设计了一种基于时域的转矩传感器快速解调方法.分析了SAW谐振器的响应特性并设计了信号的截断与去噪声方法,以及周期计算方法.根据设定的高频与响应信号周期的关系确定各个谐振器谐振频率的范围,然后通过谱估计具有最大周期的信号以解调出频率.提出的扫描方法只需采集一路信号,即降低了阅读器硬件系统的复杂性,同时在时域中简化了信号解调算法.通过实验测试了该扫描方法,完成一次搜索过程只需521ms,而传统的2路正交信号(IQ)扫描方法需要828ms.实验结果表明:设计的算法与IQ法相比扫描速度提高了37.1%,验证了该算法的有效性.

To decrease the processing time and reduce the system complexity of surface acoustic wave（SAW）torque sensor,a fast time-domain demodulation method based on the frequency response characteristic of SAW resonator was designed.The SAW response characteristic was analyzed,and a signal truncation and de-noising method were designed.The period of received was obtained by finding zero cross points.The operational frequency band was found according to the relation between the higher frequency and the period of the received signal.The resonant frequency of SAW sensor was obtained by estimating the spectrum of the signal with the maximum period.The proposed method acquires only one channel signal which reduces the complexity of the hardware system of SAW interrogator.The processing periods are completed in the time-domain which simplifies the demodulation algorithm.For a single scanning cycle,the executing time is appoximately 521 ms for the proposed method while that of the traditional method is828 ms,which verifies the proposed method.