System and method for the algebraic derivation of physiological signals

摘要

A technique for the algebraic derivation of a pulse oximetry signal uses the mathematical relations of detected light signals. First (6) and second (8) light sources transmit light through the patient's finger or reflects light off the blood vessels in the patent's finger. A light detector detects light from each of the light sources and generates a measured intensity signal. The measured intensity signal includes the true intensity of light transmitted from each of the light sources as well as noise introduced during the measurement process. A data sample from each of the light sources is digitized and subdivided into a plurality of data windows. The mathematical relationship (210) is apllied to each of the data windows (214) to determine a ratio value indicative of oxygen saturation in the patient. The ratio values (α,β) are statistically analyzed (224) to determine the best estimate for the correct ratio value (α). This ratio value is subsequently processed to determine the oxygen saturation within the patient.