一种模数混合式阻抗测量系统的设计与实现

摘要

To overcome defects of universal impedance measuring instruments and meet the demands from industry, this paper introduces an impedance measurement system based on a balance bridge using an analog-digital hybrid circuit. The system is designed to include three modules, an analog-digital hybrid circuit, a microcontroller（MCU） based signal processing and communication unit, and a host computer for display and control. The analog digital hybrid circuit includes a waveform generator, a front-end signal conditioner, a mixed bridge, bridge balance detector and controller. The MCU controls all part of the circuit and balance the bridge, transmit data to the host computer. The host computer processes the data, calculate and display impedance, transmits new parameters such as frequency and level to the MCU. The solution used in the present work is easier to implement, lower the cost, save energy and reduce size. It has a wide area of applications.%针对现有阻抗测量方式的不足和现实工业的需求，介绍了一种以模拟数字混合电桥为核心的阻抗测量系统。系统采用模块化设计，包括模数混合电路、单片机信号处理与通信、上位机显示与控制3部分。模数混合电路包括信号发生与调理、模拟前端、混合平衡电桥、平衡检测与控制。单片机控制着各部分电路，使电桥达到平衡，并将平衡参数上传给上位机，由上位机计算后得到阻抗。对频率、电压等参数的控制可以通过上位机与单片机通信后实现。系统实施方法较传统方法简单，成本和体积、功耗都大幅降低，具有很强的应用价值。