基于AD698的线性差动式位移传感器解码电路设计

Decoding Circuit Design of Linear Variable Differential Transformer Based on AD698

摘要:

线性差动式位移传感器(LVDT)由于其灵敏度高、线性度好、分辨率高、寿命长、可靠性高等优点,已广泛应用于机载测试系统中；为了设计出精度高,稳定性好,能够满足机载测试需求的LVDT传感器解码电路,分析了LVDT传感器磁芯位移与输出电压信号的关系,研究了AD698的内部解调原理,设计出了基于AD698的信号解码电路；该电路通过外围元器件产生传感器所需的激励信号,并对激励信号和传感器输出信号进行解调得到与传感器磁芯位移成正比的直流电压；最后通过实验验证该电路具有结构简单、稳定性高、精度高的优点,能够满足机载测试的要求,且该电路已经过高低温和振动试验,并成功应用于机载测试采集系统中。

Abstract:

The Linear differential displacement sensor (LVDT) has been widely used in airborne testing system, due to its high sensitivity, good linearity, high resolution, long service life and high reliability. In order to design an LVDT decoding circuit that have a high accuracy, good stability and can meet the demand of airborne testing, the relationship between core displacement and the output voltage signal of an LVDT sensor has been analyzed, the internal AD698 demodulation principle has been studied, then an signal decoding circuit based on AD698 has been designed. The circuit produces the excitation signal by peripheral components, and gets the DC voltage that is proportional to the magnetic core displacement by demodulating the excitation signal and the output signal. Then, the precision and stability of the decoding circuit has been verified, it's show that the circuit can meet the requirements of airborne test, now the circuit has been completed gentle vibration test and successfully used in airborne testing system.