程控放大器设计论文

信息与控制工程学院硬件课程设计说明书程控放大器的设计学生学号：12345678学生姓名：张三专业班级：电*****指导教师：郑老师职称：教授起止日期：2013.4.22～2013.5.10信息与控制工程学院硬件课程设计说明书-I-硬件课程设计任务书一、设计题目：程控放大器的设计二、设计目的1.掌握电子设计的一般方法，掌握放大器各项性能指标的测量方法；2.掌握用单片机最小系统硬件的设计的方法；3.熟练掌握伟福编辑软件的使用方法，掌握C51程序的设计方法。三、设计任务及要求设计并实现一程控放大器。程控放大器基本指标和设计要求：1.设计并制作一程控放大器，电压放大倍数1-20；2.通过键盘输入放大倍数，放大倍数步长为1倍；3.能够用LED七段数码管实时显示放大倍数；4.实测放大器的输入阻抗、输出阻抗、通频带。主要元器件：OP07(OP27)、DAC0832、C0851F410、LED7段显示、键盘、其它。四、设计时间及进度安排设计时间共三周（2013.4.22～2013.5.10）,具体安排如下表：周安排设计内容设计时间第一周查阅相关资料，进行电路的原理设计并画出电路原理图。学习伟福编辑软件的使用方法。2013.4.22～2013.4.26第二周进行电路的焊接制作、测试。进行软件编程并调试。2013.4.29～2013.5.3第三周完成并提交硬件设计作品及硬件课程设计说明书，硬件课程设计答辩。2013.5.6～2013.5.10五、指导教师评语及学生成绩指导教师评语:年月日成绩指导教师(签字):程控放大器的设计II目录硬件课程设计任务书······································································································I前言······················································································································1第1章程控放大器概述································································································21.1程控放大器的概述····························································································21.2程控增益放大器设计方案论证············································································21.3程控增益放大器的应用领域和意义······································································4第2章设计硬件器件简介·····························································································52.1DAC0832D/A转换器概述··················································································52.2OP07低噪声高精度运算放大器··········································································72.3C0851F410单片机概述······················································································9第3章电路设计及分析·······························································································103.1LED显示模块设计·························································································103.2键盘模块设计································································································113.3放大及D\A转换电路的设计·············································································133.4系统电源模块的电路设计·················································································13第4章软件设计········································································································154.1C语言介绍···································································································154.2Keil开发环境································································································154.3程控放大器的C语言程序················································································164.3.1整体程序和框图·······················································································164.3.2显示部分程序和框图·················································································164.3.3键盘控制模块部分····················································································174.4系统测试······································································································18结论·····················································································································20参考文献···················································································································21信息与控制工程学院硬件课程设计说明书1前言本次硬件设计的任务是制作程控放大器，要求电压放大倍数1—200倍，能够通过键盘输入放大倍数，放大倍数步长为1倍或10倍，能够用LED七段数码管实时显示放大倍数，实测放大器的输入阻抗、输出阻抗、通频带。程控放大器是一种放大倍数由程序控制的放大器，也叫可编程放大器。在多通道或多参数的数据采集系统中，多个通道或多个参数共用一个测量放大器。就每个通道的数据采集而言，还可实现自动控制增益或量程自动切换，因此程控增益放大器得到广泛应用。本文分析了程控放大器的基本原理和它用对模拟信号进行稳幅和稳零的方法。并定量分析了程控信号的可调节范围及精度。当改变量程时测量放大器的增益也相应地加以改变。这种变化通常是自动进行，即不需要人为的改变电路连接，而是通过软件控制放大器增益的改变。这样可以实现仪器量程的自动切换。另外，通过改变增益的方法使系统功能增强，在核测量中，稳谱的方法之一就是改变输入信号的放大倍数。这就需要用到数字控制放大器，并针对该仪器要解决的具体问题要求放大器的放大倍数在一定范围内变化，并且放大倍数调节要求精细。该文提供了这种数控放大的一种设计方案，它的放大倍数范围为1~20，其倍数的调节步长为1倍。本次实习我们应用C0851F410单片机、OP07放大器、DAC0832D/A转换器的概况及应用做的简单程控放大器，通过软件控制放大器增益的改变，采用这向项技术，可以使测量系统有宽的适用范围，提高系统的适应性，同时提高系统的测量精度。程控一般有两种方法，一个是模拟的，叫做自动增益控制（AGC），另外，还有先监测输出，然后调整程控增益放大器的增益，前者简单，但人工介入较麻烦，后者人工介入较简单但成本高复杂。“先监测输出，然后调整程控增益放大器的增益”是说通过编制程序去控制电路实现。本次设计主要是以DAC0832内部的电阻网作为核心，利用C0851F410单片机控制所选D/A的电阻网络状态，同时利用四个独立键盘来控制正弦波的放大倍数，并利用两位数码管，将其显示出来，形成一基础简单的程控放大器电路。程控放大器的设计2第1章程控放大器概述1.1程控放大器的概述程控放大器是指可以通过软件改变增益的放大器,也称为可编程放大器。具有高性能、多档位、控制方便等特点。程控放大器的增益由单片机输出的数字量控制，可以一个放大器进行数据采集，就每个通道的数据采集而言，还可实现自动控制增益或量程自动切换，程控放大器使用方便、性能好，故可在数据采集系统、自动增益控制、动态范围扩展、远程仪表测试等方面使用尤为适宜，程控增益调整比手工调整更优越。放大器按照集成运算放大器的参数来分，集成运算放大器可分为如下几种类型：通用型运算放大器、高阻型运算放大器、低温漂型运算放大器、高速型运算放大器、低功耗型运算放大器、高压大功率型运算放大器。考虑的参数不同各电路设计不同，我们本次实习中做到的只是简单的基础制作。程控放大器的具体模块如图1-1所示：图1-1程控放大器模块图1.2程控增益放大器设计方案论证本设计由三个模块电路构成:单片机显示与控制模块、前级数模转换电路和后级放大电路。在前级DAC电路中,用反馈电阻网控制DAC0832输出的电流量的不同，经过OP07运算放大器输出，从而改变放大器的放大倍数,实现了小信号的放大。AT89C52的单片机显示、控制和数据处理模块除可以程控调节放大器的增益外,还可以实时显示输出程控放大器的增益。程控放大器可以通过多种途径实现，下面我们简单介绍两种方案。方案一：三极管放大电路D/A数模转换模块LED显示模块键盘输入模块OP07放大模块单片机的数据处理模块信息与控制工程学院硬件课程设计说明书3简单的放大电路可以由三极管搭接的放大电路实现,图1-2为分立元件放大器电路图。为了满足增益的要求,可以采用多级放大电路实现。对电路输出用二极管检波产生反馈电压调节前级电路实现自动增益的调节。本方案虽也可以实现放大功能，但由于大量采用分立元件,如三极管等,电路比较复杂,工作点难于调整,尤其增益的定量调节非常困难。此外,由于采用多级放大,电路稳定性差,误差较大，容易产生自激现