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

[1] Santiago Lopez, “Pulse Oximeter Fundamentals and Design”, p.2 .2012
[2] S. S. Yesman, S. O. Mamilov1, D. V. Veligotsky1, A. I. Gisbrecht, “Local changes in arterial oxygen saturation induced by visible and near-infrared light radiation”,2016
[3] Filho I, Terner J et al, “Measurement of hemoglobin oxygen
saturation using Raman microspectroscopy and 532-nm excitation”
J Appl Physiol 104, 2008
[4] Dangdang Shao, Chenbin Liu, Francis Tsow, Yuting Yang, Zijian Du, Rafael Iriya, Hui Yu, Nongjian Tao,“Noncontact Monitoring of Blood Oxygen Saturation Using Camera and Dual-Wavelength Imaging System”,2016
[5] Edward D. Chan, Michael M. Chan, Mallory M. Chan “Pulse oximetry: Understanding its basic principles facilitates appreciation of its limitations”,2013
[6] M.M. Asimov “LASER-INDUCED IN VIVO OXYHEMOGLOBIN PHOTODISSOCIATION
AND ITS APPLICATION FOR LOCAL TISSUE OXYGENATION”,2008
[7] Erin K. Hanson , Jack Ballantyne, “A Blue Spectral Shift of the Hemoglobin Soret Band Correlates with the Age (Time Since Deposition) of Dried Bloodstains”, 2010
[8] Mamilov S.O., Yesman S.S., Velyhotskyi D.V., “Investigation of the photodissociation quantum efficiency of hemoglobin derivatives”,2019
[9] Yung-Hua Kao , Paul C.-P. Chao , Senior Member, IEEE, and Chin-Long Wey, “Design and Validation of a New PPG Module to Acquire High-Quality Physiological Signals for High-Accuracy Biomedical Sensing”,2019
[10] MAX30102,High-Sensitivity Pulse Oximeter andHeart-Rate Sensor for Wearable Health
[11] Joshua Hrisko” Arduino Heart Rate Monitor Using MAX30102 and Pulse Oximetry”,2019, DOI: https://reurl.cc/e3rVvm
[12] M.M. Asimov, R.M. Asimov, S.A. Mamilov, Yu.S. Plaksiy, A.N. Rubinov, A.I. Gisbrecht, ” Investigation in vivo the effect of temperature on quantum yield of photodissociation of oxyhemoglobin (HbO_2) in cutaneous blood vessels”,2007
[13] Lerson KIRASAMUTHRANON, Jeerasuda KOSEEYAPORN, Paramote WARDKEIN,” QPSK Modulator with Continuous Phase and Fast Response Based on Phase-Locked Loop”,2017
[14] Paul Horowitz, Winfield Hill, “The Art of Electronics, Kindle Edition”,2015