Patent ID: 8046041

Claim:
A pulse oximetry system comprising: an optical probe including light emitting elements and a light detecting element, said light detecting element configured to output a signal representative of light attenuated by tissue of a patient, said signal comprising signal portions and noise portions, said detecting element further configured to output a signal representative of an ambient light signal; a control circuit configured to supply control signals to the light emitting elements, the control signals configured to alternately generate light at two different wavelengths using a modulation frequency; and a patient monitor comprising: a sensor port communicating with said optical probe to receive said signal; and a processing circuit configured to process the output signal to generate a processed signal, the processing circuit comprising: an analog-to-digital converter configured to digitize the output signal to produce a digital signal, a demodulator configured to remove the modulation frequency from the digital signal, a filter having an effective cut-off frequency higher than a human pulse rate and configured to attenuate the demodulated digital signal at an ambient light frequency nearest the modulation frequency, and a calculation module configured to identify a physiological parameter of interest based at least on the filtered, demodulated digital signal; wherein the calculation module includes a self-adapting processor configured to optimize the filtered demodulated digital signal.