Patent ID: 8385995

Claim:
A physiological parameter tracking system comprising: a physiological signal input having at least first and second intensity signal components received from a light-sensitive detector that detects light of at least first and second wavelengths transmitted through body tissue carrying pulsing blood; a first calculator configured to output a reference parameter responsive to the physiological signal; a second calculator configured to output an ancillary parameter responsive to the physiological signal; a third calculator configured to output a slow parameter that is a function of the reference parameter and the ancillary parameter and is slowly varying in time relative to the reference parameter and the ancillary parameter; and a fourth calculator configured to output a physiological measurement responsive to the reference parameter and the slow parameter, wherein the fourth calculator provides a physiological measurement that is at least in part of a function of the reference parameter and the slow parameter and wherein the physiological measurement is a function of the reference parameter and the slow parameter during a first time interval and is the ancillary parameter during a second time interval.