摘要：本课题研究提高持续引流吸引器压力测量性能的方法。具体而言，是根据吸引器的基本电路的框架结构、技术标准、技术参数和运行流程，利用数学建模计算和电路仿真，从噪声分析等角度，研究前置放大器中的放大电路的参数设计与选择。58058

研究吸引器电路中由三个集成运算放大器组成的仪表放大器，各个固定电阻的变化率对该仪表放大器输出端噪声的影响，提高这种产品电路的抗噪声的性能以及优化设计。

建立运算放大器的噪声模型以及固定电阻的噪声模型，把各噪声模型代入仪表放大器电路，建立数学方程，得到输出端噪声与电阻之间的函数关系式，并做列表分析。

采用将电阻进行微变的方法，将 各电阻变化对噪声的影响情况进行比较，筛选出对输出端噪声有明显影响的电阻，并用orCAD软件建立仿真噪声电路模型，然后仿真结果验证。

仿真结果与理论分析一致，该方法可用于放大器噪声分析，对仪表放大器的电阻比选取和部分精密电阻选取提出建议。

毕业论文关键词： 放大电路；运算放大器；噪声

Study on the amplifier in continuous drainage suction unit

Abstract: The methods of improving the performance of continuous drainage suction unit are discussed. Specifically, it is according to the basic frame structure of the circuit of suction unit, technical standards, technical parameters and running process, by using mathematical modeling calculation and circuit simulation, from the aspects of noise analysis, study the preamplifier amplification circuit parameter design and selection.

Study the suction unit in the circuit composed of three integrated operational amplifier instrumentation amplifier, the rate of change of various fixed resistance to the effects of the instrumentation amplifier output noise, in order to improve the anti-noise performance of such products circuit design and optimization.

The noise models of operational amplifier and resistor are established, put the model of noise generation instrumentation amplifier circuit, mathematical equation, get the output noise and the function relation between resistance, and analysis of the list.

Using the method of micro resistance to change, will each resistance change the effect of noise in the comparison, select have obvious influence on the output noise resistance, noise of the circuit model is established with orCAD software simulation, the simulation results.

The simulation results are consistent with theoretical analysis, this method can be used in amplifier noise analysis, part of the resistance than the selection and the instrumentation amplifier precise resistance selection Suggestions are put forward.

Key words: amplifying circuit; Operational amplifier.；noise

1绪论1

1.1 课题的研究背景和意义1

1.2医疗装备的发展 1

1.3吸引器的分类与现状 2

1.4压力传感与放大器 3

1.4.1压力测量与显示电路介绍3

1.5课题需解决的主要问题 4

1.6各章节内容安排 4

2仪表放大器与电路噪声 5

2.1仪表放大器概述 5

2.2仪表放大器的设计应用 5

2.3电路噪声 8

2.3.1电阻中的噪声8

2.3.2集成运算放大器中的噪声 11

2.4噪声源的相关性 12

2.4.1噪声相关系数 12

2.4.2噪声源的迭加原理 12  

2.4.3电阻网络中噪声迭加原理 13

3电阻变化率与噪声的关系15

3.1含噪声的仪表放大器电路  15

3.2仪表放大器电路噪声计算与分析17

4.仿真验证22

4.1 orCAD软件简介 22

4.2电路分析仿真 22