Non-interfering physiological sensor system

Abstract

A system includes a light source, a photodetector in optical communication with the light source, and a processor in communication with said photodetector and configured to output a signal representing oxygen saturation independent of an interfering signal from an interfering source. The system may further include an analog-to-digital converter in communication with the processor that is configured to digitize a signal from the photodetector by oversampling and output oversampling data to the processor. The processor may include an averaging filter that averages the oversampling data received from said analog-to-digital converter prior to decimation to generate an oversampling number.

1 - 20 . (canceled) 
     
     
         21 . A system comprising:
 a light source;   at least one photodetector in optical communication with said light source;   an analog-to-digital converter in communication with said photodetector, said analog-to-digital converter being configured to oversample a signal received from said photodetector and output oversample data; and   a processor in communication with said analog-to-digital converter, said processor being configured to filter said oversample data based at least in part on an oversample number;   wherein said oversample number is derived from at least a sampling frequency of said analog-to-digital converter and a frequency of an interfering signal.   
     
     
         22 . A system as set forth in  claim 21 , wherein said filtering of said oversampled data produces a frequency response having at least one notch at a frequency corresponding to a frequency of the interfering signal. 
     
     
         23 . A system as set forth in  claim 21 , wherein said processor is configured to apply a weighted linear combination to the oversample data. 
     
     
         24 . A system as set forth in  claim 23 , wherein the weighted linear combination includes at least one of a weight and an oversample number that are varied randomly. 
     
     
         25 . A system as set forth in  claim 21 , wherein said photodetector is configured to receive the interfering signal and wherein said processor is configured to calculate a frequency of the interfering signal. 
     
     
         26 . A tissue oximeter sensor comprising:
 a light source;   a photodetector in optical communication with said light source and configured to output a signal;   a processor in communication with said photodetector and configured to output a signal representing oxygen saturation independent of an interfering signal from an interfering source, wherein said processor is configured to:
 select an oversample number based on a sampling frequency of the photodetector output signal and a frequency of the interfering signal; and 
 reduce the interfering signal in accordance with the oversample number. 
   
     
     
         27 . A tissue oximeter sensor as set forth in  claim 26 , wherein the oversample number defines a notch in a frequency response of a filter at one or more frequencies associated with the interfering signal. 
     
     
         28 . A sensor as set forth in  claim 26 , further comprising an analog-to-digital converter configured to digitize a signal from said photodetector by oversampling and further configured to output oversampling data to said processor. 
     
     
         29 . A sensor as set forth in  claim 28 , wherein said processor includes an averaging filter in communication with said analog-to-digital converter and is configured to average oversampling data received from said analog-to-digital converter. 
     
     
         30 . A sensor as set forth in  claim 29 , wherein said processor is configured to apply a weighted linear combination to the oversampling data. 
     
     
         31 . A sensor as set forth in  claim 30 , wherein the weighted linear combination includes at least one of a weight and an oversample number. 
     
     
         32 . A sensor as set forth in  claim 31 , wherein the oversample number corresponds to a frequency of the interfering signal. 
     
     
         33 . A sensor as set forth in  claim 31 , wherein the weight corresponds to a frequency of the interfering signal. 
     
     
         34 . A sensor as set forth in  claim 26 , wherein said light source and said photodetector are disposed on a sensor pad. 
     
     
         35 . A sensor as set forth in  claim 26 , wherein said light source is disposed on a first sensor pad and said photodetector is disposed on a second sensor pad. 
     
     
         36 . A sensor as set forth in  claim 26 , wherein the interfering source is a pulse oximeter configured to estimate arterial blood oxygen saturation. 
     
     
         37 . A system comprising:
 a tissue oximeter sensor having a light source in optical communication with a photodetector and a processor in communication with said photodetector;   an interfering device configured to output an interfering signal having a frequency;   wherein said tissue oximeter is configured to output a signal independent of the interfering signal output by said interfering device by:
 selecting an oversample number based on a sampling frequency and the frequency of the interfering signal; and 
 reducing the interfering signal in accordance with the oversample number. 
   
     
     
         38 . A system as set forth in  claim 37 , wherein the oversample number defines a notch in a frequency response of a filter at one of more frequencies associated with the interfering signal. 
     
     
         39 . A system as set forth in  claim 37 , wherein said tissue oximeter sensor includes an analog-to-digital converter configured to digitize a signal from said photodetector by oversampling and further configured to output oversampling data to said processor. 
     
     
         40 . A system as set forth in  claim 39 , wherein said processor includes an averaging filter in communication with said analog-to-digital converter and configured to average oversampling data received from said analog-to-digital converter.