基于环路增益的负反馈放大电路分析

The Analysis of Negative Feedback Amplifier Circuit Based on the Loop Gain

文献[1]根据|1+AF|来判断放大电路反馈极性和负反馈放大电路产生自激振荡的条件有不当之处,容易给学生造成误解。本文利用环路增益AF来判断放大电路反馈极性、反馈深度并讨论稳定性。首次采用环路增益的奈奎斯特图来分析反馈极性、反馈深度和稳定性。实验结果表明环路增益奈奎斯特图的成功引入,非常简单直观的解决了文献[1]中的不当之处,并给出了判断放大电路反馈的正负极性、反馈深度和稳定性的准确描述。

It is incorrect to judge the positive and negative polarity of amplification circuit feedback only according to|1+AF|in literature[1].The conditions of self-oscillation in the negative feedback amplifier circuit are not accurate,and it is easy to misunderstand students.Loop gain AF is used to determine the positive and negative polarity,feedback depth and stability of amplification circuit feedback in this paper.The Nyquist diagram of the loop gain is first used to analyze feedback polarity,feedback depth and stability.The experimental results express that the successful introduction of the loop gain Nyquist diagram solves the inadequacies in the literature[1]very simply and intuitively.Accurate descriptions of the judgment of positive and negative polarity,feedback depth and stability of the amplifier circuit feedback are given.