多模式高精度阻抗测量系统设计

A Design of Multimode High-precision Impedance Measurement System

针对目前应用于混凝土阻抗测量的系统结构复杂、测量精度低的问题,基于比例测量和DFT数字解调阻抗测量原理,提出了一种多模式高精度混凝土阻抗测量系统的设计。系统采用高度集成阻抗测量芯片AD5933,并利用MSP430F169单片机作为主控,结合上位机界面,能实现单频、多频阻抗测量,系统体积小、功耗低、结构简单、扩展性强。测试结果表明:系统稳定性强、测量精度高,阻抗测量范围为100Ω～10 MΩ,幅值相对误差小于0.7%,相位绝对误差小于0.8°。

Aiming at the problems of lower measuring accuracy and complexity about impedance measurement system which is applied to the concrete structure , based on the principle of proportion and DFT digital demodu-lation impedance measurement , the paper puts forward a design of multimode high -precision impedance meas-urement system.The system uses a highly integrated chip AD5933 to measure the impedance, and the MSP430 F169 MCU as the master , in combination with PC interface .The system has the function of single fre-quency and multi -frequency impedance measurement , with the characteristics of small size , low power con-sumption , simple structure and strong extensibility .The test results show that the system has high stability and high measurement precision .The range of impedance measurement is from 100Ωto 10 MΩ, relative error of impedance measurement is less than 0.7%, the absolute error of phase is less than 0.8 °.