摘要
为解决LCR表在测量容性阻抗时的自激问题,设计了一种增强测量稳定性的LCR仪表。通过分析测量前端自平衡电桥电路的相位裕度,采用相位补偿电路解决因相位滞后造成的自激问题。应用直接数字频率合成技术结合相位校准电路设计,产生相位准确的正交测量信号。使用开关鉴相式锁相放大器处理微弱信号,经16位模数转换器采集后输入到微处理器进行矢量信号合成与输出显示。相比专业仪器,所设计样机对电阻测量相对误差可达0.5%,对大电容测量相对误差可达1%。
To address the self-excitation issue in the measurement of capacitive impedance using LCR meters,an LCR instrument has been developed to enhance measurement stability.By analyzing the phase margin of the self-balancing bridge circuit at the measurement front-end,a phase compensation circuit has been employed to resolve the self-excitation problem caused by phase lag.Utilizing direct digital frequency synthesis combined with a phase calibration circuit design,quadrature measurement signals of accurate phase are generated.A switch-phase discriminator lock-in amplifier is used to process weak signals,which are sampled by a 16-bit analog-to-digital converter and input into the microprocessor for vector signal synthesis and output display.Compared to professional instruments,the prototype designed has achieved a relative error of up to 0.5%for resistance measure-ments and up to 1%for large capacitance measurements.
作者
杨学文
陈灵强
马凯元
Yang Xuewen;Chen Lingqiang;Ma Kaiyuan(School of Information and Electrical Engineering,Hebei University of Engineering,Handan 056038,China)
出处
《电子技术应用》
2024年第12期70-76,共7页
Application of Electronic Technique
关键词
自平衡电桥
相位裕度
直接数字频率合成
锁相放大器
self-balancing bridge
phase margin
direct digital frequency synthesis
phase-locked amplifier
作者简介
杨学文(2003-),男,本科,主要研究方向:电子测量;通信作者:陈灵强(1995-),男,博士,讲师,主要研究方向:数据挖掘、交通流预测,E-mail:chenlingqiang@he-beu.edu.cn;马凯元(2002-),男,本科,主要研究方向:电子测量。
