Patent ID: 7469157

Claim:
An apparatus for computing arterial signals in living tissue, said apparatus comprising: a detector configured to receive a first signal which travels along a first propagation path and a second signal which travels along a second propagation path, at least a portion of said first and second propagation paths being located in a propagation medium, wherein said first signal has an arterial signal portion that is indicative of arterial blood and another signal portion that is indicative of motion induced noise, and said second signal has an arterial signal portion that is indicative of arterial blood and another signal portion that is indicative of motion induced noise, said detector also configured to output a detector signal responsive to said first and second signals; and a signal processor responsive to representations of the detector signal and configured to generate therefrom a signal which is primarily a function of said arterial portions of said first and said second signals without significant interference from said motion induced noise.