title: Pulse oximeter improvement with an ADC-DAC feedback loop and a radial reflectance sensor.
abstract: Pulse oximeter circuitry must meet several design constraints, including the ability to separate a small pulsatile signal component from a large signal baseline. This paper describes pulse oximeter design changes that produced order-of-magnitude improvements in signal quality. The primary changes were (a) the replacement of an analog sample-and-hold-based differentiator circuit with an ADC-DAC feedback loop and (b) the replacement of a side-by-side reflectance sensor design with a radial sensor arrangement that maximizes the pulsatile-to-baseline signal ratio.
authors.affiliation: Department of Electrical & Computer Engineering, Kansas State University, Manhattan, KS, USA.
authors.forename: David
authors.initials: D
authors.lastname: Thompson
authors.forename: Austin
authors.initials: A
authors.lastname: Wareing
authors.forename: Dwight
authors.initials: D
authors.lastname: Day
authors.forename: Steve
authors.initials: S
authors.lastname: Warren
mesh_terms: D000703:Analog-Digital Conversion; D004867:Equipment Design; D019544:Equipment Failure Analysis; D010092:Oximetry / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014159:Transducers