NIU Bin, CHEN Song-jing, SUN Jing-hua, et al. The Research of Common-mode Rejection Capability of the Differential Amplifier[J]. 2009, 14(1): 92-95.DOI:
差动放大电路共模干扰抑制能力的研究
摘要
电磁流量计输出的流速信号非常微弱
且常叠加共模干扰
经信号调理电路放大后
会导致信噪比很低
甚至淹没有用信号.针对这问题提出了利用前置放大电路有效抑制共模干扰
对其进行定性、定量分析
给出实际可行的提高差动放大电路输入阻抗的设计
并进行分析、推导和对比计算
证明其可以很大限度抑制共模干扰
提高测量准确度.
Abstract
The common-mode interference is always interfused with the weak velocity signal of the electromagnetic flowmeter
which can be amplified by the signal processing circuit.This causes low signal-to-noise ratio and even submerge the velocity signal.The paper used the preamplifier to reject common-mode interference effectively.We did qualitative analysis and quantitative analysis.We also showed practical design which can improve the amplifier’s input impedence.Then we did analysis