Patent ID: 7471971

Claim:
In a signal processor for processing at least two measured signals M 1 and M 2 , where said signal M 1 comprises a physiological signal portion S 1 and may comprise a noise portion N 1 , and where said signal M 2 comprises a physiological signal portion S 2 and may comprise a noise portion N 2 , a method comprising: determining a value for a coefficient c used in a combination of M 1 and M 2 such that the combination of M 1 and M 2 approximates S 1 , wherein determining the coefficient c comprises comparing frequency domain representations of the two measured signals M 1 and M 2 ; using said coefficient c to remove at least some of the noise portion N 1 from the measured signal M 1 , thereby producing an approximation A 1 to said physiological signal S 1 ; and determining a measured output value for one or more physiological parameters based at least in part on said approximation A 1 .