Active noise cancellation in an optical sensor signal
First Claim
1. A medical device system, comprising:
- an optical sensor for producing a signal corresponding to tissue light attenuation;
a processor receiving the optical sensor signal and configured to compute a first measure of light attenuation at a first light wavelength and a second measure of light attenuation at a second light wavelength; and
noise cancellation circuitry for receiving the first measure and the second measure and generating an estimated ratio of the first and second measures, the noise cancellation circuitry providing a peak output power when the guessed ratio corresponds to an actual ratio containing the first measure;
the processor determining a tissue oxygenation using the estimated ratio corresponding to the peak output power of the noise cancellation circuitry.
1 Assignment
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Accused Products
Abstract
A medical device system and associated method are used for monitoring tissue oxygenation. An optical sensor produces a signal corresponding to tissue light attenuation. A processor receives the optical sensor signal and computes a first measure of light attenuation at a first light wavelength and a second measure of light attenuation at a second light wavelength. In one embodiment, noise cancellation circuitry receives the first measure and the second measure and generates a guessed ratio of the first and second measures. Using the first measure, the second measure and the guessed ratio, the noise cancellation circuitry provides a peak output power when the guessed ratio corresponds to an actual ratio of the first and second measures.
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Citations
25 Claims
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1. A medical device system, comprising:
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an optical sensor for producing a signal corresponding to tissue light attenuation; a processor receiving the optical sensor signal and configured to compute a first measure of light attenuation at a first light wavelength and a second measure of light attenuation at a second light wavelength; and noise cancellation circuitry for receiving the first measure and the second measure and generating an estimated ratio of the first and second measures, the noise cancellation circuitry providing a peak output power when the guessed ratio corresponds to an actual ratio containing the first measure; the processor determining a tissue oxygenation using the estimated ratio corresponding to the peak output power of the noise cancellation circuitry. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method, comprising;
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sensing an optical signal corresponding to tissue light attenuation; computing a first measure of light attenuation at a first light wavelength and a second measure of light attenuation at a second light wavelength using the sensed optical signal; generating an estimated ratio of the first and second measures; determining a reference noise signal using the estimated ratio, the first measure and the second measure; providing the reference noise signal and the first measure to an adaptive noise canceller; determining an actual ratio of the first and second measures as an estimated ratio corresponding to a peak output power of the adaptive noise canceller; and determining a tissue oxygenation using the actual ratio. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A non-transitory computer readable medium having computer executable instructions for performing a method comprising:
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sensing an optical signal corresponding to tissue light attenuation; computing a first measure of light attenuation at a first light wavelength and a second measure of light attenuation at a second light wavelength using the sensed optical signal; generating an estimated ratio of the first and second measures; determining a reference noise signal using the estimated ratio, the first measure and the second measure; providing the reference noise signal and the first measure to an adaptive noise canceller; determining an actual ratio of the first and second measures as an estimated ratio corresponding to a peak output power of the adaptive noise canceller; and determining a tissue oxygenation using the actual ratio.
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Specification