First and foremost, I gratefully extend my most sincere appreciation and deepest gratitude to my supervisor, Professor Yeo Kiat Seng, for giving me the opportunity to undertake this challenging and rewarding research project. His time, effort, support, constructive advice and valuable guidance as well as encouragement in the course of my Ph.D. candidature are deeply appreciated and will always be remembered. Special thanks also go out to the technical and support staff in NTU, School of EEE, and Centre for Integrated Circuits and Systems, for the countless help they have provided. Last but not least, I dedicate this piece of work to my family and all my friends, who believe in me and stood by me especially at times when I was facing difficulties and frustrations in accomplishing this research work. Their suggestions and encouragement had helped me tremendously in overcoming all the problems.