【正文】 中得到了廣泛地應(yīng)用，成為一種不可缺少的臨床診斷設(shè)備。血氧飽和度(SaO2)是指血液中血紅蛋白實(shí)際結(jié)合的氧氣氧含量占血液中血紅蛋白所能結(jié)合氧氣的最大量(氧容量)的百分比。主要是血紅蛋白實(shí)際結(jié)合的氧，極小量溶解于血漿的氧(%)。血氧容量正常約為20ml%。動(dòng)脈血氧分壓正常約為100mmHg，取決于吸入氣體的氧分壓和肺的呼吸功能，靜脈血氧分壓正常40mmHg，它可反映內(nèi)呼吸狀況。缺氧是臨床極常見的病理過程，是多種疾病引起死亡的最重要的直接原因。就整體而言，成年人體需氧量約為250ml/min。氧分子和血紅蛋白分子能進(jìn)行可逆的結(jié)合，血紅蛋白由氧合血紅蛋白(HbO2）和還原血紅蛋白(Hb)組成。生命的基本過程就是機(jī)體細(xì)胞攝入氧排出二氧化碳產(chǎn)生能量的過程。關(guān)鍵詞：血氧飽和度，脈搏血氧測定法，動(dòng)態(tài)光譜，硬件設(shè)計(jì)，軟件設(shè)計(jì)Digital pulse oximeter designAuthor：Chang YanchunTutor：He ZhonghaiABSTRACTPulse oximetry is a reliable, arterial, noninvasive easy continuously determining oxygen saturation to use means in virtually of any setting. Because there are still several drawbacks in the design of the pulse oximetry system and its signal processing, the system needs improving in accuracy, repetition and stability. This system is proposed based on dynamic spectroscopy measuring principle, and in this principle, under the guidance of a set of digital pulse oximetry test system. System adopts digital chip design to improve the system stability and repeatability. System using digital filter and digital demodulation method, using photoelectric pulse wave signal extracted by software. And with dynamic spectroscopy, based on the principle of the algorithm is deduced, the pulse of the highprecision measurements oxygen saturation. This subject mainly embodies the innovation and work in the following respects:First, the measuring principle of the pulse oximeter is based on traditional test method. Its accuracy is not gratifying due to various factors influencing the measurement result, such as the principle, measuring condition and individual discrepancy. In this system a new pulse oximetry based on dynamic spectroscopy (DS) is introduced, it can promote the accuracy of the pulse oximeter evidently. The dynamic spectroscopy method is able to eliminate the interference of the individual discrepancy and measuring condition in principle. This new method can eliminate the measurement error of pulse oximetry theoretically.Secondly the pulse of the traditional testing system of oxygen saturation because of plex analog caused poor stability of the system, this system puts forward the design thought according to the digitization of dynamic spectroscopy measurement principle adopts modern microprocessor, integrated circuit technology, the design of the pulse wave signal detection and collection system. We use the microprocessor driven directly by certain wavelengths of light emitting diode。并利用數(shù)字濾波和數(shù)字解調(diào)的數(shù)據(jù)處理方法，完成雙路信號分離。在動(dòng)態(tài)光譜理論的基礎(chǔ)上，對光電脈搏波信號進(jìn)行時(shí)域頻域轉(zhuǎn)換，所得到基波分量用于血氧飽和度計(jì)算，獲得了高精度的脈搏血氧飽和度測量值。提高了系統(tǒng)穩(wěn)定性和可重復(fù)性，降低了由于模擬電路不穩(wěn)定所造成的系統(tǒng)測量誤差。本課題的創(chuàng)新與主要工作體現(xiàn)在以下方面：（1）通過分析傳統(tǒng)脈搏血氧測量原理引起的測量誤差，在理論上推導(dǎo)出實(shí)現(xiàn)高精度脈搏血氧測量的方法——基于動(dòng)態(tài)光譜方法的脈搏血氧測定法，這種方法在原理上可以消除由于測量條件及個(gè)體差異等多方面因素對測量精度的影響。系統(tǒng)采用數(shù)字濾波和數(shù)字解調(diào)的方法，用軟件提取光電脈搏波信號。本課題提出了基于動(dòng)態(tài)光譜的脈搏血氧測量原理，并且在該原理的指導(dǎo)下，設(shè)計(jì)了一套數(shù)字化脈搏血氧檢測系統(tǒng)。 畢業(yè)設(shè)計(jì)(論 文)數(shù)字式脈搏血氧儀設(shè)計(jì)系 別自動(dòng)化工程系專 業(yè)生物醫(yī)學(xué)工程班 級50616姓 名常衍春指導(dǎo)教師賀忠海2010 年 6 月 10 日 東北大學(xué)秦皇島分校畢業(yè)設(shè)計(jì)（論文） 第51頁摘 要 脈搏血氧儀是一種可連續(xù)、無創(chuàng)、方便地檢測動(dòng)脈血氧飽和度的儀器。由于其在系統(tǒng)設(shè)計(jì)和信號處理方法上存在的缺陷,使它在測量的精度、重復(fù)性、穩(wěn)定性等方面還存在需要探討和完善的地方。系統(tǒng)采用純數(shù)字芯片設(shè)計(jì)，提高了系統(tǒng)穩(wěn)定性和重復(fù)性。并在動(dòng)態(tài)光譜原理基礎(chǔ)上，根據(jù)推導(dǎo)出的算法，獲得了高精度的脈搏血氧飽和度測量值。（2）針對傳統(tǒng)的脈搏血氧飽和度檢測系統(tǒng)中因模擬電路復(fù)雜而引起的系統(tǒng)穩(wěn)定性和重復(fù)性差的問題，本文提出了數(shù)字化的設(shè)計(jì)思想，根據(jù)動(dòng)態(tài)光譜測量原理采用現(xiàn)代微處理器、集成電路技術(shù)，設(shè)計(jì)了脈搏波信號的檢測、采集及處理系統(tǒng)。（3）采用數(shù)字解調(diào)的方法對采樣的數(shù)字信號解調(diào)為雙路光信號，并用軟件提取光電脈搏波。 本系統(tǒng)在硬件方面設(shè)計(jì)了以MSP430為核心的信號檢測和采集系統(tǒng)，并結(jié)合了雙波長頻分法和過采樣技術(shù)，在提高分辨率和信噪比的同時(shí)，大大簡化了硬件電路。研究了容積脈搏波的軟件提取和檢出，并在通過傅立葉變換得到光電脈搏波的基波分量，用于血氧飽和度計(jì)算。 receiving tube will receive light signals into electrical signals, high frequency converter by the direct current, pulse wave signal carry photoelectric instead of digital signal, the hardware circuit and AC drive circuit source separation circuit. Reuse digital filter to replace filter circuits, analog circuits to save a part of signal and system this filter system stability and repeatability, reduced due to the instability of analog circuit is caused by the measurement error of the system. Finally, using digital demodulation method to sample signal demodulation of digital signal, the dual light for extracting photoelectric pulse wave by software. On the basis of the theory of dynamic spectroscopy, conversing photoelectric pulse wave signal from frequency to division and the ponent be used in the blood oxygen saturation calculation. In this system, the hardware design MSP430 as the core to signal detection and collection system, bining with the dual wavelength frequency division method of sampling technology and in improving the resolution and signaltonoise ratio, greatly simplified the hardware circuit. Use digital filter and digital demodulation of the data processing method to double signal separation. Study the volume of pulse wave extraction from the software, and through a Fourier transform of photoelectric pulse wave get ponent for the blood oxygen saturation.KEY WORDS： Oxygen saturation, pulse oximetry, dynamic spectroscopy, hardware design, software design目 錄1 緒 論 1 血氧飽和度的概念及其生理意義 1 脈搏血氧飽和度測量儀的發(fā)展歷程 2 脈搏血氧飽和度測量儀的現(xiàn)狀 3 本系統(tǒng)的研究意義及主要內(nèi)容 42 脈搏血氧飽和度的測量理論基礎(chǔ)及動(dòng)態(tài)光譜理論 6 光電容積脈搏波的產(chǎn)生原理 6 脈搏波的產(chǎn)生原理 6 光電容積脈搏波描記法（PPG）原理 72. 2 脈搏血氧飽和度測量的理論基礎(chǔ)與算法 8 郎伯－比爾(LambertBeer)定律及應(yīng)用 8 離體血氧飽和度測量原理 9 傳統(tǒng)脈搏血氧測定法 12 基于動(dòng)態(tài)光譜的脈搏血氧檢測原理 13 修正的朗伯－比爾定律 13 動(dòng)態(tài)光譜理論 13 基于DS的脈搏血氧測量原理 14 基于DS的脈搏血氧算法與傳統(tǒng)算法精度比較 153 基于DS的脈搏血氧檢測系統(tǒng)的數(shù)字化實(shí)現(xiàn)方法 17 傳統(tǒng)脈搏血氧儀測量系統(tǒng)回顧 17 基于DS的脈搏血氧測量系統(tǒng)的系統(tǒng)硬件組成 18 總體設(shè)計(jì)思想與系統(tǒng)構(gòu)成 18 基于MSP430系統(tǒng)平臺的外圍電路設(shè)計(jì) 19 光源及其驅(qū)動(dòng)電路的設(shè)計(jì) 19 電路板及各芯片的電源設(shè)計(jì) 22 串口設(shè)計(jì)及外USB座的設(shè)計(jì) 23 外接存儲設(shè)備設(shè)計(jì)及鋰電池充電管理設(shè)計(jì) 24 液晶模塊及其驅(qū)動(dòng)電路設(shè)計(jì) 26 基于MSP430平臺系統(tǒng)的設(shè)計(jì) 26 基于DS的脈搏血氧儀的數(shù)字化測量方法 31 雙波長頻分測量法及信號的數(shù)字解調(diào) 314 系統(tǒng)軟件設(shè)計(jì) 34 Embedded Workbench開發(fā)平臺和調(diào)試器CSPY的簡單介紹 34 初始化程序 35 主程序設(shè)計(jì) 37 按鍵和顯示程序設(shè)計(jì) 39 系統(tǒng)誤差分析 41總結(jié) 43致謝 44參考文獻(xiàn) 45附錄 46附錄A：英文翻譯 46附錄B：系統(tǒng)整體原理圖設(shè)計(jì) 501 緒 論 血氧飽和度的概念及其生理意義 足夠的氧是所有生命活動(dòng)的物質(zhì)基礎(chǔ)。人體吸入氧氣，在肺部的肺泡內(nèi)與毛細(xì)血管進(jìn)行氣體交換。當(dāng)組織得不到充足的氧，或不能充分利用氧時(shí)，組織的代謝、機(jī)能、甚至形態(tài)結(jié)構(gòu)都可能發(fā)生異常變化，這一病理過程稱