通用可变增益放大器_报告.docx
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通用可变增益放大器作者:杨带稳 钟水安 吴土华作者单位:广东科学技术职业学院 邮编:519090摘要:本着简单、准确、可靠通用的原则,采用了分级设计匹配互联的思想。本放大器以AD603为核心构成可变增益放大器的实现电路,以带宽大的运放芯片AD811和MAX412作为辅助放大。系统分为过压保护电路、前级跟随电压输入电路、增益放大电路、程控增益电路、增益档位控制选择电路、输出功率驱动电路、单片机显示电路七个部分组成。全系统采用模拟电路方式,通过前级电压跟随部分获得所需输入电压、输入阻抗等重要参数。通过档位控制的电路部分实现四个档位增益值转换,在衰减电路的作用下得到四个档位的增益值,即-20dB至0、0至20dB、20dB至40dB和40dB至60dB,还有用单片机通过AD转换来控制系统放大器的增益,从而达到程序控制的,增益值显示在单片机控制的1602中,最后通过后级获得输出幅度不低于8V的输出电压。关键词:增益放大,模拟电路,电压跟随,程控增益Abstract: In a simple, accurate, and reliable general principle, adopts a hierarchical design matching Internet thinking. The amplifier which is taking AD603 as the core of the variable gain amplifier circuit, with a large bandwidth amplifier chip AD811 and MAX412 as the auxiliary magnifying. System for overvoltage protection circuit, before following the voltage input circuit, gain of the amplifier circuit, programmable gain amplifier circuit, a gain control circuit, the output gear selection of power drive circuit, SCM display circuit is composed of seven parts. The system adopts analog circuit, through the preceding stage voltage follower portion to obtain the desired input voltage, input impedance and other important parameters. Through the gear position control circuit part four stalls gain value conversion, the attenuation circuit obtained under the action of four stalls in the gain value, namely the - 20dB to 0, 0 to 20dB, 20dB to 40dB and 40dB to 60dB, also useful SCM through AD conversion to control the gain of the amplifier, so as to achieve program control, gain the value shown in the MCU control 1602, finally obtained after output amplitude less than 8V output voltage.Key words: gain amplifier, analog circuit, a voltage follower, programmable gain~~~~~~~~~~~~~~~~~~目录~~~~~~~~~~~~~~~~~~一、方案比较与论证11. 剖析赛题12.各方案比较与选择21)增益控制模块:22)输入电压跟随23)程控增益模块24)后级增益模块35)输出功率驱动电路3二、体统硬件设计31. 系统的总体设计32.模块电路设计51)前级输入跟随模块电路(如图2所示)52)AD603增益控制模块电路(如图3所示)63)增益档位控制模块电路64)输出功率驱动电路75)程控增益电路8三、系统软件设计81.程控增益模块的流程92.各模块的仿真设计9四、系统的组装91.PCB板图101)电路原理图请参照附录(二)102)电路PCB图请
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