摘要进入信息化时代以来，科学技术日新月异，工业化程度愈来愈高，要保证产 品的高质量与加工的高精度，我们需要对产品的检测提出更高的要求。因此，我 们需要更加精密的检测工具。检测与加工是密不可分的，然而无论是加工还是检 测环节，传感器在其中都起着不可替代的作用。相比于其它传感器，电容式传感 器具有结构简单、动态特性好、可非接触测量、分辨率高，并能在高温、强辐射 和强震动等恶劣环境下工作，在众多邻域应用广泛。然而，电容式传感器将被测 非电量转化为电容变化后，其信号是十分微弱的，不好直接测量，所以我们一般 都会采用测量电路将其转化为电压、电流或频率信号来进行显示、传输与研究。84535

目前，国内生产的电容测微仪或多或少存在着这样或那样的问题，如漂移大、 工作可靠性不高、精度不高等问题，一直与国外的传感器水平保持一定的差距。 在超精密加工技术迅猛发展的今天,这种测量精度越来越达不到当代加工技术的 要求。鉴于此，本论文所选课题便于电容式传感器有关，本文主要研究内容是电 容式位移传感器及其测量电路，确定电路能检测到传感器电容 C1 与 C2 之差的 最小值，并且选定当 C1-C2<最小值时激励源频率上限值和下限值。不同于当前 的主流研究方向，本设计将大胆的以方波作为激励源，这在国内属于首创。本文 将采用交流不平衡电桥、差动脉冲宽度调制电路和运算法则测量电路这三种方案 进行研究，以期在能实现仿真的基础上，未来能够做出实物，能为我国的超精密 研究领域贡献一部分力量。

毕业论文关键词：电容；位移传感器；方波；测量电路

Abstract Since entering the information age, science  and  technology with each passing day, more and more high degree of industrialization, to ensure the high quality of products and processing of high precision, we need to put  forward  higher requirements for product testing。Therefore, we need more sophisticated testing tools。Detection and processing are inseparable, however, whether it is processing or testing, the sensor plays an irreplaceable role。Compared with other sensors, capacitive sensor has a simple structure, good dynamic characteristics, non contact measurement, high resolution, and can work in high temperature, strong radiation and  strong vibration and other harsh environment, in a wide range of applications。However, capacitive sensor will be measured non electricity transformation as a change in capacitance, the signal is very weak, not directly measured, so we will generally by measuring circuit will be converted to voltage, current or frequency signal to display, transmission and research。

At present, the domestic production of capacitance micrometer  exists more or less in one way or another, such as drift, low reliability, accuracy is not high, has been with foreign level sensor keep a certain gap。Today, the rapid development of ultra precision machining technology, the accuracy of this measurement is not up to the requirements of the modern processing technology。For this reason,The topic selected in this thesis is convenient for the capacitive sensor,The main research contents of this paper is a capacitive displacement sensor and its measuring circuit,  determining circuit can detect sensor capacitor C1 and C2, the difference between the minimum value, and selected when C1-C2< when the minimum value of excitation source frequency limit value and the lower limit value。Different from the current mainstream research direction, this design will be bold to square wave as a source of inspiration, which is the first in the country。This paper will use an AC unbalanced bridge, differential pulse width modulation circuit and operational principle of the measurement circuit these three schemes, to can realize simulation based, in the future to make in kind, for the ultra precision research field with a part of the force。