文档介绍：大学
2012届学士学位论文
多级放大器的频率响应研究
学院、专业物理与电子信息学院
电子信息工程
研究方向电子技术
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学号
指导教师姓名
指导教师职称教授
2012年
多级放大器的频率响应研究
摘要放大器作为电子线路的重要组成部分,承担着对信号的放大功能。频率响应是放大器的主要性能指标,其表明了放大器对于不同频率信号的放大功能。本文首先推导出多级放大器放大倍数与各级放大器放大倍数之间的关系式,然后以基本放大电路为出发点,分析其对于高频、中频和低频三个不同频段信号的放大能力,并讨论其截止频率,得出影响放大器频率特性的主要因素。接着推导出多级放大器的频率响应表达式,并推导出多级放大器截止频率与各级放大器截止频率的关系式。可以得出多级放大器的通频带由各级放大器通频带所决定,且其通频带小于组成它的各级放大器的通频带的结论。最后采用Multisism软件进行仿真,对理论结果进行验证,从而得出结论。
关键词放大器;多级放大器;频率响应;截止频率;Multisim
The research of multistage amplifier's frequency response
Abstract As the important part of electronic circuits ,amplifier assumes the signal amplification. The frequency response is the amplifier's main performance index, which indicates the amplifier for amplification of different frequency signals. First,this paper deduced the relation between the multistage amplifier amplification and the amplifier amplification at all levels .Second, with the basic amplifying circuit as the starting point,it discussed the amplification capability of high frequency, medium frequency and low frequency in three different frequency band signal, and then discussed the cutoff frequency of amplifier and thus we can obtain the main factors which impacts the amplifier frequency characteristics. Thirdly, the expression of the frequency response of multistage amplifier, the expression of the relation between the multistage amplifier cut-off frequency and the amplifier amplification cut-off frequency at all levels are deduced in this article .So we can draw the conclusion that the multistage amplifier passband is determined by amplifier passband at all levels and the passband is less than the passband of the amplifier at all levels. At last the theoretical results is simulated by using Multisism software and then lead to the conclusion.
Keywords Amplifier; Multistage amplifier; Frequency response; Cutoff frequency;
Multisim
目次
1 引言 1
2 密勒定理及晶体管的混合Π等效模型 2
密勒定理 2
晶体管的混合π等效模型 2
3多级放大器的频率响应 3
频率响应的定义 3
多级放大器的基本形式 5
多级