SIGNAL PROCESSING APPARATUS AND METHOD
First Claim
1. A noninvasive physiological monitor comprising a signal processor communicating with a detector responsive light attenuated by body tissue, said detector producing a detector output waveform, said signal processor receiving said detector output waveform and configured to transform said detector output waveform into a spectral domain waveform, configured to identify a series of spectral data and frequencies corresponding to said spectral data in said spectral domain waveform, and to apply a plurality of rules to said spectral data and said corresponding frequencies in order to determine an estimate for a pulserate.
3 Assignments
0 Petitions
Accused Products
Abstract
A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain. The pulserate is found by identifying the largest spectral peak in the second spectral domain.
-
Citations
1 Claim
-
1. A noninvasive physiological monitor comprising a signal processor communicating with a detector responsive light attenuated by body tissue, said detector producing a detector output waveform, said signal processor receiving said detector output waveform and configured to transform said detector output waveform into a spectral domain waveform, configured to identify a series of spectral data and frequencies corresponding to said spectral data in said spectral domain waveform, and to apply a plurality of rules to said spectral data and said corresponding frequencies in order to determine an estimate for a pulserate.
Specification