1、摘 要脉搏血氧仪是一种可连续、无创、方便地检测动脉血氧饱和度的仪器。血氧饱和度的监测目前在急救病房、手术室、监护室、患者的术后恢复、呼吸睡眠的研究以及社区医疗监护等方面得到广泛的应用。同时随着人们对健康关注度的提高，在家庭中也有很大前景。随着微光机电系统技术、生物医学技术及数字信号处理技术的发展，脉搏血氧检测系统正朝着集成化、微型化、数字化方向发展。本设计基于传统的透射式光电采集原理，使用高速集成模拟混合信号芯片C8051F320，设计了双波长血氧脉搏仪。系统采用光源调制、频分测量法和过采样技术，简化模拟电路部分的设计，提高了系统稳定性和重复性。在动态光谱原理基础上，对光电脉搏波信号进行时域频
2、域转换，所得到基波分量用于血氧饱和度计算，获得了高精度的脉搏血氧饱和度测量值。本文还研究了脉搏血氧仪现况，Lambert-Beer定律在光电采集模型分析与应用，以及光电容积脉搏波描记法、双波长测量法的原理。以及国内外血氧脉搏测量仪的现况。根据脉搏血氧仪的功能和需求，采取便于实时传输的USB通信来进行数据的传输。采集到的结果可以方便的和传送到数据库进行分析对比。便利的采集方式可以增加数据库的容量，为医院、疾病防疫站等机构对疾病的分析统计提供依据。本设计还包括脉搏血氧仪的软硬件设计及实现。对于硬件先进行原理上的设计仿真，再进行试验样板的制作与验证。软件的设计包括了采集电路信号控制和采集以及USB数
3、据的传输和上位机。最后分析了影响测量精度的各种因素，提出了消除各种干扰信号的处理方法。关键字：C8051F320、USB、脉搏血氧仪、透射、Lambert-Beer定律AbstractPulse oximetry is a continuous, non-invasive and easily way to measure SaO2. Currently, blood oxygen saturation monitoring is widely applicant in the emergency ward, operating rooms, care of patients, postope
4、rative recovery, breathing the sleep research and community medical ward, etc. At the same time as people take more care to health, pulse oximetry also has very great prospects in the family. As micro- optical -electro-mechanical system technology, biomedical technology and digital signal processing
5、 technology developed, blood oxygen detection system is going to be more integration, miniaturization, digital. The design is based on the traditional transmission photoelectric collection principle, using high-speed integrated simulation of mixed signal chips C8051F320; design the blood oxygen doub
6、le wave pulse instrument. System by using lamp-house modulating, frequency division of measurement and sampling technology, simplify the analog circuit part of the design; improve the stability of the system and the repeatability. In dynamic spectrum based on the theory of photoelectric pulse wave s
7、ignal in the time domain frequency conversion, get base wave component used in the blood oxygen saturation calculation, won the high precision of the pulse of blood oxygen saturation measured values. The paper also studies the pulse oximetry status, Lambert-Beers law in photoelectric acquisition mod
8、el analysis and application of the photoelectric volume and pulse wave tracing, double wavelength measurement principle. And the current status of measurement in the oxygen pulse at home and abroad. According to the pulse oximetry function and demand, take easy real-time transmission USB communicati
9、on for data transmission. The collected results can be convenient and transmit the comparative analysis to the database. The collection of convenient way to increase the capacity of the database, for hospitals, disease of disease institutions such as defensive stand of statistical analysis, provides
10、 the basis. The design also includes pulse oximetry hardware and software design and realization. When design the hardware, I do a simulation in 0computer to make sure that the circuit diagram didnt have problems, and then did I come to make test circuit board. The programming includes tow parts. Fi
11、rst one is on the micro-chips which is setting LED control signal, converts the input voltage signals into digital quantity and sent it to computer through USB. The other part is on the computer which uses to show the messenger and save it. At last, do the analyzed of various factors influence the a
12、ccurate measurement, and give some way to solve those problems.Key word: C8051F320, USB, pulse oximetry, transmission, Lambert-Beers law目 录第一章 绪论11.1引言11.2血氧饱合度的测量意义21.3血氧饱合度测量的发展状况21.4 国内外研究现状31.5本论文研究的目的和内容41.6本章小结4第二章 无创血氧饱和度脉搏测量的原理和方法52.1 非侵入式脉搏血氧仪的工作原理52.2 Lambert-Beer定律52.3光电测量原理72.4光电容积脉搏波描记法
13、82.5双波长测量法9第三章 硬件电路的设计133.1整体电路设计133.2电源设计143.3 双波长发光驱动电路设计153.4 光电转换电路的设计163.5信号分离电路183.6 带通滤波器设计183.7放大电路的设计213.8直流偏置电路223.9本章小结22第四章 程序设计234.1 C8051F320 混合信号微控制器介绍244.2整体程序设计264.3 发光管驱动程序设计284.4 AD采集程序设计284.4.1采用过采样技术提高数据采集精度284.4.2 AD采集相关寄存器配置314.4.3 血氧量的计算314.4 USB通信程序设计32第五章 系统分析与实验345.1 干扰信号产
14、生的原因及处理方法345.1.1环境光、暗电流345.1.2工频和其它电磁干扰345.1.3运动伪差355.2 实验测量结果355.2总结与展望37谢 辞38参考文献39附 录411. C8051F320最小系统原理图：412. 信号采集放大电路原理图：413. 芯片下载线原理图：43第一章 绪论1.1引言氧是生命活动的基础，缺氧是导致许多疾病的根源，而较为普遍的病症如慢性低血氧症，脑与心血管供血不足以及运动后的疲劳等生理和病理现象都与人体氧含量有直接关系，严重时直接威胁人的生命常用的血氧指标有:氧分压:为溶解于血液的氧所产生的张力。动脉血氧分压正常约为100mmHg，取决于吸入气体的氧分压和
15、肺的呼吸功能，静脉血氧分压正常40mmHg，它可反映内呼吸状况。氧容量:为l00ml血液中血红蛋白(Hb)为氧充分饱和时的最大带氧量，应等于l.34mL/gHb(g%)，它取决于血液中Hb的质(与氧结合的能力)和量。血氧容量正常约为20ml%。氧含量:为l00ml血液中血红蛋白实际的带氧量。主要是血红蛋白实际结合的氧，极小量溶解于血浆的氧(仅有0.3ml%)。与氧结合的血红蛋白称为氧合血红蛋白(HbO2)，与氧离解的血红蛋白称为还原血红蛋白。血氧饱和度(SaO2)是指血液中(血红蛋白)实际结合的氧气(氧含量)占血液中(血红蛋白)所能结合氧气的最大量(氧容量)的百分比。因此，血氧饱和度的定义可表示为血氧饱和度的表示方法有两种：1、 功能饱和度（functional saturation）： (1-1)式中CHbO2和CHb分别表示组织中氧合血红蛋白和脱氧血红蛋白的浓度，SaO2表示血氧饱和度值，即血液中血氧的浓度。之后采用的SaO2表示利用脉搏血氧仪所测得的血氧饱和度的值。2、自然饱和度（fractional saturation）： (1-2)除了病理因素和长期吸烟者外，人体血液中所含碳氧血红蛋白和高铁血红蛋白是很少的。所以临床上多采用功能饱和度来反映
