DOI: 10.1063/5.0053825

Abstract

 This paper proposes a synchronous demodulation technology based on sample-and-hold (SH), which shows significant advantages in the application of precision sensors. The traditional synchronous demodulation methods are discussed, and then the working principle of the proposed method is theoretically analyzed in detail. It is found that the proposed method can effectively suppress the harmonic components caused by the signal source, but is also benefit to improve the dynamic range of precision sensors. Eddy current sensor is adopted as an example of precision sensors, and a high-precision eddy current displacement sensor prototype was designed and tested. The results show that with the proposed method, the harmonics in the output signal are suppressed more effectively, and the demodulation circuit is relatively simplified. This synchronous demodulation method has an extensive application prospect in precision sensors.

文章摘要

  本文提出了一种基于采样保持（SH）的同步解调技术，在精密传感器的应用中具有明显的优势。文中对传统的同步解调方法进行了简要介绍，并从理论上详细分析了新提出方法的工作原理。分析结果表明，本方法可以有效地抑制信号源引起的谐波分量，同时提高精密传感器的动态范围。文中以电涡流传感器为例对这种解调方法进行了实际应用，设计并测试了高精度电涡流位移传感器样机。实验结果表明，该方法能更有效地抑制输出信号中的谐波，使解调电路相对简化。这种同步解调方法在精密传感器中有着广泛的应用前景。

图片摘要

  在不同-3dB截止频率低通滤波器滤波的情况下，本文中提出的采样保持解调方法（红色曲线）和传统相敏检波方法（蓝色曲线）对输入正弦信号的解调结果（频谱）。(a)截止频率为0.1kHz；(b) 截止频率为10kHz；(c) 截止频率为100kHz；(d)输入信号的频谱。

   相比于传统的相敏检波方法（蓝色曲线），本文中提出的采样保持同步解调方法（红色曲线）在后接低通滤波器截止频率分别为0.1kHz、10kHz和100kHz时均表现出更好的输出谐波抑制能力。

亮点：

  提出通过采样保持对传感器输出信号进行同步解调的方法，该方法电路结构简单，解调性能优良，相比于传统的相敏检波等解调方法，可以获得更好的谐波抑制能力。