穿戴式裝置的崛起讓人們注意到可以使用微小晶片去接收我們所需要的生理訊號，包含了心跳、血氧、以及血壓等等的身體資訊。穿戴式裝置主要是應用於手環以及心律調節器等等。而量測血氧則是在心血管疾病診斷中具有重要作用，藉由手環我們可以掌握當下的心率以及血氧，有助於我們去判斷身體的各種狀況。
在市售的手環中，是藉由光體積變化描記圖法(PPG)透過紅光與紅外光在含氧血紅素以及去氧血紅素上的吸收率差異，所計算出來的血氧值。再透過知道熱紅外光可以增加對人體的血液循環以及對人體的血氧產生光解離效應，可以思考如何經由結合PPG晶片以及熱紅外光刺激，在同一個系統上達成刺激以及檢測是否血氧有變化，並且用實驗去驗證是否不同的刺激條件會有不同的效率。
　 在此篇論文中，經由先了解光體積變化描記圖法訊號(PPG)，並且實際去找尋PPG sensor量測，並且經由Max30102的光體積變化描記圖法(PPG)感測晶片去收集數據，經過Matlab以及Simulink的數據分析，去驗證是否紅外光刺激能造成心率上以及血氧上的變化。透過實驗結果即可做出一個感測及刺激系統的雛型，經由市面上的PPG感測計去接收訊號，並且在輸出心跳訊號之後，再經由離散電路所組成之相位追蹤器，回傳訊號至刺激光源，得以達到刺激訊號可以跟隨心跳頻率產生，進而達到刺激效果最大化。

關鍵字 : 光體積變化描記圖法，血氧，資料分析，心率，血氧光解離效應，訊號追蹤，紅外線發光二極體

The rise of wearable devices has drawn attention to the use of tiny chips to record physiological signals such as heartbeat, blood oxygen, and blood pressure. Wearable devices are mainly used in wristbands and heart rate regulators. The measurement of blood oxygen plays an important role in the diagnosis of cardiovascular diseases. With a wristband, we can monitor heart rate and blood oxygen in real time, which helps us to judge various conditions of the body.
In commercially available wristbands, the blood oxygen value is derived from the difference between the absorption rates of red light and infrared light through Photoplethysmography on oxyhemoglobin and deoxyhemoglobin. By knowing that thermal infrared light can enhance the blood circulation of the human body and produce a photodissociation effect on the blood oxygen of the human body, we can think about how to stimulate and detect blood oxygen on the same system by combining PPG chips with thermal infrared light stimulation. Subsequently, we could study whether different stimulation conditions have different efficiencies.
In this thesis, by first understanding the PPG signal, and collecting data through the integrated PPG sensor chip of Max30102, the data are analyzed in Matlab and Simulink, to verify whether infrared light stimulation can cause changes in heart rate and blood oxygen. Through the experimental results, a prototype of a PPG sensing and stimulation system is designed. The signal is received by commercial PPG sensor, and the heartbeat signal is derived for a phase tracker composed of discrete circuits. The tracking signal is sent to the stimulation light source, so that the stimulation signal can be synchronized with the heartbeat frequency, thereby maximizing the stimulation effect.

Keywords: Photoplethysmography, blood oxygen, data analysis, heart rate, Photodissociation effect of blood oxygen, signal tracking, Infrared light-emitting diode

一、緒論(Introduction) 1
1.1 氧氣在人體中的行為 1
1.2 人體皮膚經過紅外光照射後的反應 1
1.3 論文架構 2
二、相關研究發展(Related work) 4
2.1光體積變化描記圖法(PPG) 4
2.2血氧以及光解離相關之實驗結果 7
三、前導實驗(Pilot experience) 14
3.1 研究假設 14
3.2 研究設計 14
3.2.1 實驗一 : 不同位置光以及距離之刺激 15
3.2.2 實驗二 : 不同頻率光刺激 16
3.3 儀器使用 18
3.3.1 微處理器控制板 Arduino Uno 19
3.3.3 波形產生器 PXle-5433 21
3.4 量測結果之正確率以及錯誤示範 21
3.5 實驗結果 24
3.5.1 實驗一 : 不同位置光刺激 25
3.5.1.1 刺激位置: 第一節指腹 25
3.5.1.2 刺激位置: 第一節指背 26
3.5.1.3 刺激位置: 第二節指腹 26
3.5.1.4 刺激位置: 第二節指背 27
3.5.2 實驗二 : 不同頻率光刺激 28
四、資料分析以及驗證(Proof & Data Analysis) 31
4.1 實驗結果分析 31
4.1.1 原始數據(Raw Data check) 31
4.1.2 血流大小數值校正(Shifting) 32
4.1.3 血氧計算(SpO2) 33
4.1.4 心跳分析(Heart rate) 34
4.1.5 計算相位以及鎖相迴路(Phase check & PLL) 34
五、離散電路之架構以及結果 38
5.1 離散電路系統 38
5.2 離散電路量測與假設是否吻合 39
5.2.1 心跳訊號處理 39
5.2.2 Phase Lock Loop(PLL) 41
5.2.3 Voltage Control Oscillator(VCO) 45
5.2.4 實際量測結果 49
六、結論及未來工作 52
6.1 結果整理 52
6.2 結果討論以及研究限制 52
6.3 未來工作 53
參考文獻 55
附錄 A 數據量測列表 57
附錄 B 實驗數據 58

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