Non-interfering physiological sensor system
View Patent ↗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. A system comprising:
a light source;
at least one photodetector in optical communication with said light source; and
a processor in communication with said photodetector and configured to output a signal independent of an interfering signal caused by an interfering sensor; and
an analog-to-digital converter in communication with said processor and configured to digitize a signal from said photodetector by oversampling and output oversampling data to said processor;
wherein said processor includes an averaging filter in communication with said analog-to-digital converter and configured to average the oversampling data received from said analog-to-digital converter prior to decimation based on an oversampling number associated with a sampling frequency of the analog-to-digital converter and a frequency of the interfering signal, wherein the oversampling number defines notches in a frequency response of the filter at one or more frequencies associated with the interfering signal.
2. A system as set forth in claim 1 , wherein said averaging filter includes a notch before decimation, wherein said notch has a frequency that corresponds to a frequency of the interfering signal.
3. A system as set forth in claim 1 , wherein said processor is configured to apply a weighted linear combination to the oversampling data.
4. A system as set forth in claim 3 , wherein the weighted linear combination includes at least one of a weight and an oversampling number that are varied randomly.
5. A system as set forth in claim 1 , wherein said photodetectors are configured to receive the interfering signal and wherein said processor is configured to measure a frequency of the interfering signal.
6. A system as set forth in claim 1 , wherein at least one of said photodetectors is configured to detect the interfering signal from the interfering sensor.
7. A tissue oximeter sensor comprising:
a light source;
a photodetector in optical communication with said light source; and
a processor in communication with said photodetector and configured to output a signal representing oxygen saturation independent of an interfering signal caused by an interfering source, wherein the processor is configured to:
select an oversampling number based on a sampling frequency and a frequency of the interfering signal, wherein the oversampling number defines notches in a frequency response of a filter at one or more frequencies associated with the interfering signal, and
reduce the interfering signal in accordance with the oversampling number.
8. A sensor as set forth in claim 7 , an analog-to-digital converter in communication with said processor and configured to digitize a signal from said photodetector by oversampling and further configured to output oversampling data to said processor.
9. A sensor as set forth in claim 8 , 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.
10. A sensor as set forth in claim 9 , wherein said processor is configured to apply a weighted linear combination to the oversampling data.
11. A sensor as set forth in claim 10 , wherein the weighted linear combination includes at least one of a weight and the oversampling number.
12. A sensor as set forth in claim 11 , wherein the weight corresponds to a frequency of the interfering signal.
13. A sensor as set forth in claim 7 , wherein said light source and said photodiode are disposed on a sensor pad.
14. A sensor as set forth in claim 7 , wherein said light source is disposed on a first sensor pad and said photodetector is disposed on a second sensor pad.
15. A sensor as set forth in claim 7 , wherein said photodetector is configured to detect a frequency of the interfering signal.
16. 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 sensor 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 sensor by:
selecting an oversampling number based on a sampling frequency and the frequency of the interfering signal, wherein the oversampling number defines notches in a frequency response of a filter at one or more frequencies associated with the interfering signal, and
reducing the interfering signal in accordance with the oversampling number.
17. A system as set forth in claim 16 , wherein said tissue oximeter sensor includes an analog-to-digital converter in communication with said processor and configured to digitize a signal from said photodetector by oversampling and further configured to output oversampling data to said processor.
18. A system as set forth in claim 17 , 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.