测量放大器共模抑制能力的分析

Analysis of the Common-mode Rejection Ability of Instrumentation Amplifier

测量放大器具有很强的抑制共模信号的能力,但由于电路的分析过程非常复杂,通常只在电路理想情况下,给出电路的差模增益。本文在电路非理想的情况下,分析了测量放大器抑制共模信号的机理,给出了放大器的差模、共模增益以及共模抑制比表达式。结论对测量放大器的设计和应用具有一定的指导意义。

The common-mode rejection ability of instrumentation amplifier is powerful, but as the analysis is complicated, the expression of differential-common gain only can be obtained under the ideal circuit. In this paper, based on the non-ideal circuit, the principle of common-mode rejection of instrumentation amplifier is analyzed, and the expression of differential-common gain, common-mode gain and common-mode rejection ratio are also given.This is significant for the design and application of the instrumentation amplifier.