LVDT数字解调方法研究

给出一种基于LVDT的数字解调系统。为了准确地测量铁芯的位置，提出了以基于FPGA的嵌入式系统平台的数字解调系统。与以往方法不同的是不仅对所得次级线圈信号采用加减法，还采用比率检测方法，通过多点的测量得到其线性系数。运用线性插值算法计算误差修正表，并且运用一种映射关系得出铁芯的真实位移值，克服了模拟电路的种种缺点，大大减小误差，还提高了线性度。通过实验证明，此数字解调系统精度最高可达万分之三。

Design of Digital Demodulation System Based on LVDT

A digital demodulation system based on LVDT is presented. A digital demodulation system on the basis of FPGA embedded system platform is proposed to accurately detect the location of core. Different from previous methods, not only the add and subtract methods, but also the methods of detection rate are used for the obtained signal from a secondary coil. In this paper, the linear coefficient is obtained by multi-point measurement, the linear interpolation algorithm is em- ployed to calculate the values of error correction, and one kind of mapping is adopted to obtain the true displacement of core. All of the shortcomings of the analog circuit are overcome. The error is greatly reduced and the linearity is increased by the method. The experiment shows that the accuracy of the digital demodulation system is up to 3 5×10-4.