作者：唐金元, 王翠珍, 于潞
作者单位：海军航空工程学院青岛分院, 山东 青岛 266041
关键词：放大电路; 电压信号; 共模噪声; 共模抑制比; 平衡
摘要：
测量仪器性能的好坏在很大程度上取决于其前端放大电路的性能,常选择具有较强噪声抑制能力和较大输入阻抗的运算放大电路和仪用放大电路。在微小电压的精密测量时,仪用放大电路的对称性很难完全保证,在强噪声的环境中,在仪用放大电路中加入共模电压的负反馈电路可抵消共模噪声或其中的一部分;在长距离信号传输时,在电路输入端加入跟随器电路可很好地克服由于测量电缆较长造成的输入电路不平衡而引入的测量误差。实验测试结果表明:改进型的仪用放大电路噪声抑制效果良好。
Anti-common-mode noise design for amplifier circuit during weak voltage signal measurement
TANG Jin-yuan, WANG Cui-zhen, YU Lu
Qingdao Branch of Navy Aeronautical Engineering Institute, Qingdao 266041, China
Abstract: The quality of measurement instruments usually was determined by the quality of their front amplifier, so those amplifiers with higher input impedance and stronger ability of anti-noise were chosen for using in computing circuits and instrumental circuits. When weak voltage signal is needed to be measured accurately, the symmetry of the instrumental amplifiers is difficult to realize. The authors proposed to add negative feedback circuit with common-mode voltage in instrumental amplifiers to totally or partly offset the common-mode noise in the strong noise environment, and add following circuit at the input end to decrease the measurement error caused by the imbalance of inputting circuit when the signal need to be transmitted in a long distance. The experimental results proved that the improved instrumental amplifier can effectively restrain common-mode interference.
Keywords: amplifier circuit; voltage signal; common-mode noise; CMRR; balance
2012, 38(4): 83-85,109 收稿日期: 2011-11-4;收到修改稿日期: 2012-1-13
基金项目:
作者简介: 唐金元(1965-),男,山东莱阳市人,教授,主要从事航空无线电领域的教学和科研工作。
参考文献
[1] 诸邦田. 电子电路实用抗干扰技术[M]. 北京:人民邮电出版社,2004:267-300.
[2] 于镭,田家彩,陈振喜. 带模拟光耦隔离的信号放大电路的设计[J]. 微型机与应用,2010(7):15-20.
[3] 童诗白. 模拟电子技术基础[M]. 北京:高等教育出版社,2005:368-370.
[4] 江孝国. 高精度、高稳定度的应变计测量差动放大电路[J].信息与电子工程,2010(5):573-576.
[5] Kay A. 运算放大电路固有噪声的分析与测量[J]. 世界电子元器件,2010(6):40-43.
[6] 裴松. 一种高共模抑制比的仪用放大电路的设计[J]. 电子产品世界,2002(4):62-64.
[7] 姜苇. 新型高共模抑制比胜利电信号前置放大器设计的研究[J]. 仪器仪表学报,2003(4):184-186.
[8] 杜祥岭,王景利,曹福刚. 传感器精密放大电路的实验研究[J]. 实用测试技术,2002(1):24-27.
