An AFE based Embedded System for Physiological Computing by Md. Nazrul Islam Khan A thesis submitted to the School of Graduate and Postdoctoral Studies in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical and Computer Engineering Department of Electrical, Computer and Software Engineering Faculty of Engineering and Applied Science Ontario Tech University Oshawa, Ontario, Canada November 2019 © Nazrul Khan, 2019 THESIS EXAMINATION INFORMATION Submitted by: Md. Nazrul Islam Khan Doctor of Philosophy in Electrical and Computer Engineering Thesis Title: An AFE based Embedded System for Physiological Computing An oral defense of this thesis took place on November 11, 2019 in front of the following examining committee: Examining Committee: Chair of Examining Committee Dr. Ying Wang Research Supervisor Dr. Mikael Eklund Examining Committee Member Dr. Ruth Milman Examining Committee Member Dr. Akramul Azim University Examiner Dr. Patrick Hung External Examiner Dr. Ana Luisa Trejos The above committee determined that the thesis is acceptable in form and content and that a satisfactory knowledge of the field covered by the thesis was demonstrated by the candidate during an oral examination. A signed copy of the Certificate of Approval is available from the School of Graduate and Postdoctoral Studies. ii ABSTRACT The present hospital-based health care system will be burdened because of the growing aging population. Aging and stress result in cardiovascular diseases that cost around seventeen million lives globally every year. To control cardiovascular ailments, at- home monitoring of blood pressure is very important which helps diet control and promote medication adherence. The present health monitors are by default bulky, daunting, invasive, and not suitable for home use. The de-facto architecture of such systems entails discrete sensors and analog sub-systems known as the analog front end (AFE) for biosignal acquisition, conditioning, and vital bridging function. Being discrete and analog, signal processing is limited. Besides, with large form factor, component counts and power consumption increase with the constant need for calibration. For more than one century, the non‐invasive measurement of blood pressure has relied on the inflation of pneumatic cuffs around a limb. In addition to being occlusive and thus cumbersome, clinical cuff‐based methods, provide intermittent BP readings, hence impeding the suitable monitoring of short‐term BP regulation mechanisms. Cuff‐based methods may not be a true representative of BP. Therefore, the development of novel technologies that eliminate the use of pneumatic cuffs is justified. In this thesis, I present a highly integrated programmable AFE based biosignal computing platform, named TasDiag. TasDiag is a novel, integrated, remote platform capable of multimodal biosignal computing including non-invasive, continuous, and cuff- less BP estimation based on pulse transit time. Being integrated, and digital, TasDiag is a single board solution with an auto calibration scheme implemented through novel signal processing and computing. The developed system is validated using real-time data from human subjects and subjected to various statistical analyses for performance and accuracy. Test results show TasDiag comply with the Association for Advancement for Medical Instrumentation standard and can replace its industry-standard counterparts. Keywords: health monitor; blood pressure; analog front end; pulse transit time; single board computer. iii AUTHOR’S DECLARATION I hereby declare that this thesis consists of original work of which I have authored. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I authorize the university of Ontario Institute of Technology to lend this thesis to other institutions or individuals for the purpose of scholarly research. I further authorize University of Ontario Institute Technology to reproduce this thesis by photocopying or by other means, in total or in part, at the request of other institutions or individuals for the purpose of scholarly research. I understand that my thesis will be made electronically available to the public. The research work in this thesis that was performed in compliance with the regulations of University of Ontario Institute of Technology’s Research Ethics Board under REB Certificate number 14522. Md. Nazrul Islam Khan iv STATEMENT OF CONTRIBUTIONS Part of the work has been published as: 1. N. Khan and J. M. Eklund, “A highly Integrated Computing Platform for continuous, non-invasive BP estimation”, IEEE Canadian conference on Electrical and Computer Engineering (CCECE), Quebec, Canada, 2018. 2. J. M. Eklund and N. Khan, “A bio-signal computing platform for real-time online health analytics for manned space missions”, IEEE Aerospace conference, Montana, USA, 2018. 3. N. Khan and J. M. Eklund, "A Programmable Integrated AFE‐Based Embedded System for Continuous, Non‐Invasive Blood Pressure Monitoring," submitted to IEEE Transaction on Biomedical Circuits and Systems, November 2019 I performed all the testing and writing of the manuscript. v DEDICATION To my beloved father, who taught me humanity and my resilient mother, who championed the tenants of education. vi ACKNOWLEDGEMENTS Research is an undertaking to extend knowledge through a disciplined inquiry or systematic investigation. To take such an undertaking, it requires huge personal commitments and the active support of a team of people. For that, my heartfelt thanks to: My advisor Dr. Mikael Eklund, for giving me total freedom for exploration. Since the very first day of this PhD, he has encouraged me to solve the problem through critical thinking, motivating with thoughtful ideas, supporting the useful points, and criticizing the wrong ones. His all-out support has been the key element of the success of my thesis. His well-reasoned and analytic view of my research has wisely guided this PhD thesis. Outside the purview of supervision, I found him responsible, considerate, and a true gentleman with amazing personal qualities. My past boss, Mr. Brian Jervis, who inked his initial on my application in support of my PhD study and my employer Sheridan College to sponsor my study partly. Dr. Farzad Rayegani, who landed his full support for my study. My family physician, Dr. Rohit Nagpal, who handed me a book on cardiovascular physiology after knowing my research topic. My colleagues Dr. Subir, Mr. Paul Kemp, Mr. Nigel Johnson, Mr. Stefan Korol, Dr. Weijing Ma, Dr. Zohreh Motamedi and Dr. Mouhamed Abdulla for their valuable support, expertise, and encouragement. The support team at the Electronics lab at Sheridan College, namely Mr. Tom King, Lawrence Porter, and others. Mr. Tom King took the extra mileage to help me out whenever there is a need. His relentless support in providing logistics is paramount to my research. Also, Mr. Carl Barnes and Mr. Kevin from Technological Arts for their ability in populating the PCB. The team of engineers at Microchip, Mr. Andre Nemat, Mr. Zhang Feng, and Mr. Ryan Bartling for their fruitful and active support to my research. Whenever I am stuck with the development tool or the Microcontroller, Andre Nemat was my first contact. For any signal processing need, Zhang and Ryan always in my help. Their theoretical and vii practical knowledge of signal processing has undeniably guided my research work. Mr. Hugh Dixon at Ledstar Inc., and Mr. Don Jackson at Labcenter, who endowed me answers regarding schematic design and PCB making. All the volunteers, who participated in the research. Fazlul Karim, Madan Talukder, Masud, Moni, and Sharif who were always available to provide their health data. All my friends, especially, Dr. Harun of BUET and Mr. Mahabub for their all-around encouragement. All my family members, for their unconditional support. My sister Dr. Anwara and my cousin, Dr. Malek for their relentless enthusiasm. My father and mother in law, who showed great interest in knowing the latest state of my research. My since departed mother, who had always shown eagerness to see this research a success. My daughter, Tasnia, who keeps encouraging me every step of the way and is immensely proud of me for this endeavor. My wife, Shikha, for traveling life with me. viii CONTENTS ABSTRACT .....................................................................................................................ii AUTHOR’S DECLARATION ....................................................................................... iv STATEMENT OF CONTRIBUTIONS ........................................................................... v DEDICATION ................................................................................................................ vi ACKNOWLEDGEMENTS ........................................................................................... vii LIST OF FIGURES ........................................................................................................ xii LIST OF TABLES ........................................................................................................ xvi GLOSSARY ................................................................................................................ xviii Chapter 1 : Introduction ................................................................................................. 1 1.1 Motivation ................................................................................................................