论文部分内容阅读
随着电子技术的不断发展及其应用的日益广泛,对电子设备中放大器的质量指标(如增益的稳定性,非线性失真,通频带等)提出了更高的要求。满足上述要求的重要手段之一,就是采用负反馈。例如,高级音响中的放大器要求非线性失真很小和带宽较宽,如果不采用负反馈,这些要求就难以达到。因此,现代电子设备中的放大器,几乎没有不采用负反馈的。 1.什么叫反馈 在讲负反馈之前,要先讲讲什么叫反馈。为了说明反馈的概念,我们先从图1所示的电视机伴音音频放大电路说起。电路由三级构成:T1管构成第一级共射放大电路,T2管构成第
With the continuous development of electronic technology and its increasingly wide range of applications, the quality of amplifiers in electronic equipment (such as gain stability, nonlinear distortion, passband, etc.) put forward higher requirements. One of the important means to meet the above requirements is to use negative feedback. For example, amplifiers in advanced audio require very little nonlinear distortion and wide bandwidth, which can be difficult to achieve without the use of negative feedback. Therefore, amplifiers in modern electronic equipment use almost no negative feedback. 1. What is the feedback Before talking about negative feedback, we must first talk about what is meant by feedback. To illustrate the concept of feedback, let’s start with the television audio audio amplifier shown in Figure 1. Circuit consists of three levels: T1 tube constitutes the first level of cascade amplifier circuit, T2 tube constitute the first