无线声表面波传感信号的正交采样处理

声表面波(SAW)延迟线型无线传感器测量系统中，信号在反射栅上的延迟时间随着被测量的变化而发生改变．如何提取回波信号上的延时信息是提高传感器精度的关键．理论分析和实验都表明，以往采用的相干I、Q解调测量相位方法存在着较大的相位测量误差．为进一步减小这些误差，引入了基于多相滤波的正交变换方法对无线SAW信号进行检波处理，在数字域中实现整倍抽取和延迟校正滤波，实现信号的正交采样．仿真和实验结果表明，正交采样法能够消除模拟解调所带来的误差．这种方法既提高了相位检测精度．也保证系统容易实现．最后，给出了测试系统的硬件实现方案．

Quadrature Sampling of the Wireless Surface Acoustic Wave Sensor Signals

The delay time represents the variations of some parameter measured in delay-line type of the SAW sensors, so the precise extraction of the delay information from the reflected wave is the key in the process. In order to improve the sensitivity and resolution of wireless SAW sensor,the method of (quadra)-ture coherent detection which is based on the poly-phase filtering was used to process the signals of reflected wave. The results of both the simulation and experiment demonstrate that this quadrature sampling method can greatly reduce the error of the measuring system and also make the system easy to implement. In the end, the hardware of the system was given.