Integrated circuits and electrode interfaces for noninvasive physiological monitoring.
This paper presents an overview of the fundamentals and state of the-art in noninvasive physiological monitoring instrumentation with a focus on electrode and optrode interfaces to the body, and micropower-integrated circuit design for unobtrusive wearable applications. Since the electrode/optrode-body interface is a performance limiting factor in noninvasive monitoring systems, practical interface configurations are offered for biopotential acquisition, electrode-tissue impedance measurement, and optical biosignal sensing. A systematic approach to instrumentation amplifier (IA) design using CMOS transistors operating in weak inversion is shown to offer high energy and noise efficiency. Practical methodologies to obviate 1/f noise, counteract electrode offset drift, improve common-mode rejection ratio, and obtain subhertz high-pass cutoff are illustrated with a survey of the state-of-the-art IAs. Furthermore, fundamental principles and state-of-the-art technologies for electrode-tissue impedance measurement, photoplethysmography, functional near-infrared spectroscopy, and signal coding and quantization are reviewed, with additional guidelines for overall power management including wireless transmission. Examples are presented of practical dry-contact and noncontact cardiac, respiratory, muscle and brain monitoring systems, and their clinical applications.
Sohmyung
S
Ha
Chul
C
Kim
Yu M
YM
Chi
Abraham
A
Akinin
Christoph
C
Maier
Akinori
A
Ueno
Gert
G
Cauwenberghs
D055615:Electrical Equipment and Supplies; D004566:Electrodes; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*