中文摘要：

本文在计算和仿真说明共射-共基反馈放大器的开、闭环源互阻增益满足反馈放大器的基本关系基础上,分别采用EWB软件和MATLAB对高频小信号等效电路作出组合电路的频率特性曲线,两者的关系曲线相同。时间常数开路法的结果表明,很小的共基极输入电阻,很大程度上削弱了密勒倍增效应,提升了组合电路的上限频率,但因结电容较大,其上限频率仍然最低,在整个系统中起主要作用,同时各极点的闭环上限频率与开环上限频率之比,近似等于源反馈深度。这种借助分析电路各极点的时间常数,讨论系统频率特性的方法,为探讨多极点系统带来了方便。

英文摘要：

Based on the simulation and calculation of source transimpedance gain of open and closed loop common emitter-common base circuits that satisfies the basic relation of feedback amplifier,the frequency characteristic curves of combinational circuits with high-frequency small signal equivalent models are derived by EWB and MATLAB software,the results indicate that the curves of the two methods are the same. Though the Miller effect is largely weakened with the small common input resistance,the results of time constant open method show that the limit frequency of the circuit is still low for the junction capacitance of the circuit is larger,it is also play the main role in the circuit. The results also indicate that the times with comparing closed loop to open loop upper limit frequency is the source feedback depth. The method that discusses the frequency characteristics of combinational circuits with the helping of analysis of time constant of each pole brings convenience to study the multi polar system.