可控增益放大器

摘要

随着时代的发展，科技的进步，微电子技术、计算机网络技术和通信技术等等也在不断地更新换代，可控增益放大器被广泛的应用到各个领域当中。可控增益放大器的核心为可控增益放大电路，人们对其研究也在不断加深，其技术也越来越成熟。

放大器是通信系统和其他电子系统中必不可少的一部分，可控增益放大电路模块在很大程度上决定了系统的整体指标。可控增益放大器是放大器的一个分支，它在通信系统中也有着非常重要的作用，于是人们对它的要求也会越来越高。在通信和电子设备中，常常采用放大器实现信号的放大，要求其线性好，具有足够的增益来抑制后级电路的噪声对系统的影响，并且增益最好可调，当输入信号大范围变化时，能自动控制增益，输出稳定的信号，另外输出功率也能达到最大。

可控增益放大器，也就是在放大器的基础上加上控制增益部分。在实际电路中，例如带负反馈的运放电路，其反馈电阻如果设为可调电阻，那么这个放大电路的增益就可以控制了，当然在其中还有许多其他的变化。

采用MSP430单片机实现数据采集及控制放大器的放大倍数，通过键盘输入实现输出状态控制、带宽选择以及增益步进控制，晶显示器显示所设置的状态及参数。

关键词：放大器，增益，单片机

ABSTRACT

With the development of The Times，the progress of science and technology，microelectronics technology，computer network technology and communication technology，and so on are also constantly upgrading，controllable gain amplifier is widely applied to various fields.The core of the controllable gain amplifier for controllable gain amplifier circuit，are also deepening the research，its technology is becoming more and more mature.

Amplifier is an indispensable part of communication system and other electronic systems，the controllable gain amplifier circuit module to a great extent，determines the overall index of the system.Controllable gain amplifier is a branch of the amplifier，it also has a very important role in the communication system，so people will more and more high to the requirement of it.In communications and electronics equipment，often signal is realized by using the amplifier amplification，ask its good linear，with sufficient gain to suppress the noise level circuit after the impact on the system，and gain the best adjustable，when a wide range of input signal changes，can automatic gain control，stable output signal，and output power can achieve maximum.

Controllable gain amplifier，that is，on the basis of the amplifier with gain control part.In the actual circuit，operational amplifier circuit with negative feedback，for example，if the feedback resistance as the adjustable resistance，then the gain of the amplifier circuit can control，in which there are many other changes，of course.

Data acquisition and control is realized by using MSP430 single chip microcomputer，the larger the amplifier amplification by keyboard input output state control，choice of bandwidth and gain step control，crystal display shows and parameters set by the state.

Keywords:amplifier；Circuit gain；SCM

目录

摘要.................................................................................................................................I ABSTRACT........................................................................................II 1前言 (1)

1.1课题的背景以及选题的意义 (1)

1.2放大器的种类 (1)

1.3宽带放大器的简介 (2)

1.4设计要求 (3)

2设计方案 (4)

2.1电路设计的几种方案 (4)

2.2系统总体设计 (5)

2.2.1前置放大电路 (6)

2.2.2末级功率放大电路 (7)

2.2.3增益控制模块 (9)

3电路硬件设计 (11)

3.1电路总体结构 (11)

3.2 AD811介绍 (11)

3.3 AD603介绍 (12)

4系统软件设计 (15)

4.1 Protues简介 (15)

4.2 CCS介绍 (17)

4.3 MSP430f249简介 (20)

4.4主程序设计 (22)

结论 (23)

参考文献 (24)

致谢 (25)

附录 (26)