METHODS AND SYSTEMS FOR EQUALIZING PHYSIOLOGICAL SIGNALS

• US 20140275878A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Abandoned Application

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Lisogurski, Daniel
• Application Number:
  US13/842,571
• Publication Number:
  US 20140275878A1
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker

Abstract

A physiological monitoring system may determine an equalized physiological signal. The system may receive a light signal that includes undesired signal features associated with a channel response. The system may equalize the light signal to mitigate the undesired signal features. The equalization may be performed on an analog signal or a digital signal. The equalization may include, for example, applying an inverse response of the channel response, such that undesired signal features are mitigated while signal features associated with a subject are retained. The equalization may be implemented with, for example, a finite impulse response filter.

Claims

1. A method for determining an equalized physiological signal, the method comprising:

receiving, using processing equipment, a light signal representing light attenuated by a subject, wherein the light signal comprises first and second repeating portions, and wherein the light signal includes an undesired channel response of a channel; and

equalizing, using processing equipment, the light signal to mitigate the undesired channel response.

2. The method of claim 1, wherein more light is emitted during the first repeating portion than during the second repeating portion.

3. The method of claim 1, wherein equalizing the signal comprises equalizing using a finite impulse response (FIR) filter.

4. The method of claim 1, wherein equalizing the light signal comprises equalizing using a time domain equalizer.

5. The method of claim 1, wherein the undesired channel response comprises a phase shift, a frequency dependent phase shift, a droop, a rise time, a fall time, an overshoot, an undershoot, a ringing, or any combination thereof.

6. The method of claim 1, wherein equalizing the light signal comprises equalizing based on a model of components in the channel.

7. The method of claim 1, wherein equalizing the light signal comprises equalizing based on training.

8. The method of claim 1, wherein the undesired channel response comprises a droop generated based on a high pass filter effect of the channel.

9. The method of claim 1, wherein the undesired channel response comprises a phase shift.

10. The method of claim 1, further comprising determining, using the processing equipment, a physiological parameter of the subject based on the equalized light signal.

11. The method of claim 10, wherein determining a physiological parameter comprises determining a parameter selected from the group consisting of blood oxygen saturation, blood pressure, heart rate, respiration rate, respiration effort, and any combination thereof.

12. A system for determining an equalized physiological signal, comprising:

processing equipment configured to;

receive a light signal representing light attenuated by a subject, wherein the light signal comprises first and second repeating portions, and wherein the light signal includes an undesired channel response of a channel; and

equalize the light signal to mitigate the undesired channel response.

13. The system of claim 12, wherein more light is emitted during the first repeating portion than during the second repeating portion.

14. The system of claim 12, wherein the processing equipment is configured to use a finite impulse response (FIR) filter to equalize the light signal.

15. The system of claim 12, wherein the processing equipment is configured to use a time domain equalizer to equalize the light signal.

16. The system of claim 12, wherein the undesired channel response comprises a phase shift, a frequency dependent phase shift, a droop, a rise time, a fall time, an overshoot, an undershoot, a ringing, or any combination thereof.

17. The system of claim 12, wherein the processing equipment is further configured to equalize the light signal based on a model of components in the channel.

18. The system of claim 12, wherein the processing equipment is further configured to equalize the light signal based on training.

19. The system of claim 12, wherein the undesired channel response comprises a droop generated based on a high pass filter effect of the channel.

20. The system of claim 12, wherein the undesired channel response comprises a phase shift.

21. The system of claim 12, wherein the processing equipment is further configured to determine a physiological parameter of the subject based on the equalized light signal.

22. The system of claim 21, wherein the physiological parameter is selected from the group consisting of blood oxygen saturation, blood pressure, heart rate, respiration rate, respiration effort, and any combination thereof.