设计简介
接收机增益自动控制电路的设计
摘 要
自动增益控制电路已广泛用于各种接收机、录音机和信号采集系统中，另外在光纤通信、微波通信、卫星通信等通信系统以及雷达、广播电视系统中也得到了广泛的应用。
本课题主要研究应用于无线接收机的前级电压放大，因此设计的电路需容纳的频带范围应较宽，以至于使语音信号通过。由于信号的脉冲宽度是0.3微秒，重复频率1.875千赫兹，幅度波动范围是1.5-3.0伏，电路应该实现增益的闭环调节，通过此电路可以实现增益的自动调整，以至于使视频信号强时自动减小放大器的倍数，信号弱时自动增大放大器的倍数，从而实现信号的自动调节。
本课题介绍了自动增益控制的概念原理以及对自动增益控制放大器各部分的工作原理，最后对系统的测试结果以及设计与实现中应该注意的问题也做了详细分析。
关键词： 放大器；自动增益控制； 电压跟随器； 滤波器
The design of receiver automatic gain control electric circuit
Abstract
The automatic gain control electric circuit has been widely used in all kinds of receivers、tape recorders and signal gathering systems, and also been used in communications system radar, the broadcast television system and optical fiber communications, microwave communications, satellite communications.
This topic mainly studies to the applies to the front level voltage amplification of the audio frequency amplification, therefore the frequency band scope of the electric circuit should be wider that can make the pronunciation signals to pass. Because the frequency band scope of the pronunciation signal is 0.3 microseconds, so the frequency band scope of our electric circuit should be designed within 1.875 KHz. And the electric circuit should realize the closed loop adjustment between 1.5 volt and 3.0 volt which increases, it may realize the automatic control through this electric circuit which increases when the tonic train signal is strong automatically that it can reduce the multiple of the amplifier, and when the signal is weak that it can automatically increase the multiple of the amplifier , so that can realize the volume with automatic control.
This topic also introduced in the concept principle of the automatic gain control as well as to automatically increases the amplifier every part of principle of work the detailed introduction, and it pays attention to the question to the test result of this system .Finally we have make some analysis to the design.
Key words：Amplifier； Automatic Gain Control； Voltage follower；Filter
目 录
绪论 ………………………………………………………………………………………..1
1 自动增益控制………………………………………………………………………………1
1.1自动增益控制电路（AGC）存在的意义 ......………………………………………..1
1.2自动增益控制的基本概念…………………………………………………………......2
1.3自动增益控制的原理 …………………………………………………………………3
1.4自动增益控制放大器…………………………………………………………………..4
1.5本课题的研究内容 ………………………………………………………………...5
2 自动控制电路增益的计算…………………………………………………………………6
2.1 自动控制增益计算 …………………………………………………………………..6
2.2 主要性能指标………………………………………………………………………….7
2.3 电路类型……………………………………………………………………………….9
2.4 可控制增益放大器……………………………………………………………………10
3 自动增益控制放大器的电路设计 ………………………………………………………14
3.1 电路原理图 …………………………………………………………………………..14
3.2 电路元器件选择………………………………………………………………………14
4 输出信号波形图…………………………………………………………………………...21
4.1 主放大器基本原理……………………………………………………………………21
4.2 主放大器………………………………………………………………………………21
4.3 自动频率控制电路（907、928组合）………………………………………………28
4.4 波形图…………………………………………………………………………………29
结论………………………………………………………………………………………….31
致谢 ………………………………………………………………………………………….32
参考文献……………………………………………………………………………………..34
摘 要
自动增益控制电路已广泛用于各种接收机、录音机和信号采集系统中，另外在光纤通信、微波通信、卫星通信等通信系统以及雷达、广播电视系统中也得到了广泛的应用。
本课题主要研究应用于无线接收机的前级电压放大，因此设计的电路需容纳的频带范围应较宽，以至于使语音信号通过。由于信号的脉冲宽度是0.3微秒，重复频率1.875千赫兹，幅度波动范围是1.5-3.0伏，电路应该实现增益的闭环调节，通过此电路可以实现增益的自动调整，以至于使视频信号强时自动减小放大器的倍数，信号弱时自动增大放大器的倍数，从而实现信号的自动调节。
本课题介绍了自动增益控制的概念原理以及对自动增益控制放大器各部分的工作原理，最后对系统的测试结果以及设计与实现中应该注意的问题也做了详细分析。
关键词： 放大器；自动增益控制； 电压跟随器； 滤波器
The design of receiver automatic gain control electric circuit
Abstract
The automatic gain control electric circuit has been widely used in all kinds of receivers、tape recorders and signal gathering systems, and also been used in communications system radar, the broadcast television system and optical fiber communications, microwave communications, satellite communications.
This topic mainly studies to the applies to the front level voltage amplification of the audio frequency amplification, therefore the frequency band scope of the electric circuit should be wider that can make the pronunciation signals to pass. Because the frequency band scope of the pronunciation signal is 0.3 microseconds, so the frequency band scope of our electric circuit should be designed within 1.875 KHz. And the electric circuit should realize the closed loop adjustment between 1.5 volt and 3.0 volt which increases, it may realize the automatic control through this electric circuit which increases when the tonic train signal is strong automatically that it can reduce the multiple of the amplifier, and when the signal is weak that it can automatically increase the multiple of the amplifier , so that can realize the volume with automatic control.
This topic also introduced in the concept principle of the automatic gain control as well as to automatically increases the amplifier every part of principle of work the detailed introduction, and it pays attention to the question to the test result of this system .Finally we have make some analysis to the design.
Key words：Amplifier； Automatic Gain Control； Voltage follower；Filter
目 录
绪论 ………………………………………………………………………………………..1
1 自动增益控制………………………………………………………………………………1
1.1自动增益控制电路（AGC）存在的意义 ......………………………………………..1
1.2自动增益控制的基本概念…………………………………………………………......2
1.3自动增益控制的原理 …………………………………………………………………3
1.4自动增益控制放大器…………………………………………………………………..4
1.5本课题的研究内容 ………………………………………………………………...5
2 自动控制电路增益的计算…………………………………………………………………6
2.1 自动控制增益计算 …………………………………………………………………..6
2.2 主要性能指标………………………………………………………………………….7
2.3 电路类型……………………………………………………………………………….9
2.4 可控制增益放大器……………………………………………………………………10
3 自动增益控制放大器的电路设计 ………………………………………………………14
3.1 电路原理图 …………………………………………………………………………..14
3.2 电路元器件选择………………………………………………………………………14
4 输出信号波形图…………………………………………………………………………...21
4.1 主放大器基本原理……………………………………………………………………21
4.2 主放大器………………………………………………………………………………21
4.3 自动频率控制电路（907、928组合）………………………………………………28
4.4 波形图…………………………………………………………………………………29
结论………………………………………………………………………………………….31
致谢 ………………………………………………………………………………………….32
参考文献……………………………………………………………………………………..34
