Control of spectral agressors in a physiological signal montoring device

• US 9,439,150 B2
• Filed: 04/12/2013
• Issued: 09/06/2016
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Carlson, David L., Stanslaski, Scott R., Cong, Peng, Denison, Timothy J., Linde, David E., Jensen, Randy M.
• Primary Examiner(s): Abbaszadeh, Jaweed A
• Assistant Examiner(s): Hicks, Austin
• Application Number:
  US13/862,227
• Publication Number:
  US 20140276185A1
• Time in Patent Office: 1,243 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• 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
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: H04W 52/0238 where the received signal is an unwanted signal, e.g. interference or idle signal
• CPC Class Codes: H04W 52/0274 by switching on or off the equipment or parts thereof
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

This disclosure describes techniques for controlling spectral aggressors in a sensing device that uses a low power sleep mode to manage the power consumed by the device. In some examples, the techniques for controlling spectral aggressors may include configuring one or more of an algorithm processing rate for a processor, a buffering rate for the processor, a sampling rate for an analog-to-digital converter, an execution unit processing rate for the processor, and an algorithm subdivision factor for the processor such that spectral interference caused by a sleep cycle rate of the processor occurs outside of one or more target frequency bands of a sampled signal. The techniques of this disclosure may be used to reduce noise in a sensing system that uses a low power sleep mode to manage the power consumed by the device.

Claims

1. A signal monitoring device comprising:

a power source;

a power distribution network electrically coupled to the power source;

an analog-to-digital converter electrically coupled to the power distribution network and configured to sample an input signal to produce a sampled signal; and

a processor electrically coupled to the power distribution network and configured to cycle between an algorithm processing mode and a sleep mode based on a sleep cycle rate,

wherein the sleep cycle rate causes spectral interference to propagate through the power distribution network and into the sampled signal via the analog-to-digital converter, and

wherein the sleep cycle rate further causes the spectral interference that is generated due to the sleep cycle rate to occur in the sampled signal at one or more frequencies that are outside of a target frequency band of the sampled signal.

2. The device of claim 1, wherein the sleep cycle rate is configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

3. The device of claim 2, wherein the sleep cycle rate is configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the sampled signal.

4. The device of claim 2, wherein the sleep cycle rate is configured such that the sleep cycle rate is less than a lower bound frequency of the target frequency band of the sampled signal.

5. The device of claim 1,

wherein the processor is further configured to invoke instances of a processing algorithm at an algorithm processing rate to process the sampled signal,

wherein the sleep cycle rate is configured to be equal to the algorithm processing rate, and

wherein the algorithm processing rate is configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

6. The device of claim 5, wherein the algorithm processing rate is configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the sampled signal or less than a lower bound frequency of the target frequency band of the sampled signal.

7. The device of claim 1,

wherein the analog-to-digital converter is a first analog-to-digital converter, wherein the input signal is a first input signal, wherein the sampled signal is a first sampled signal,

wherein the device further comprises a second analog-to-digital converter configured to sample a second input signal to produce a second sampled signal,

wherein the processor is further configured to invoke instances of a processing algorithm at an algorithm processing rate to process the second sampled signal,

wherein the sleep cycle rate is configured to be equal to the algorithm processing rate, and

wherein the algorithm processing rate is configured such that the spectral interference caused by the sleep cycle rate occurs in the first sampled signal at the one or more frequencies that are outside of the target frequency band of the first sampled signal.

8. The device of claim 7, wherein the algorithm processing rate is configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the first sampled signal or less than a lower bound frequency of the target frequency band of the first sampled signal.

9. The device of claim 1,

wherein the analog-to-digital converter is further configured to sample the input signal at a sampling rate,

wherein the processor is further configured to buffer the sampled signal at a buffering rate, the buffering rate being indicative of a number of data samples to buffer per invocation of a processing algorithm,

wherein the processor is further configured to invoke instances of the processing algorithm at a rate equal to a quotient of the sampling rate divided by the buffering rate to process the sampled signal,

wherein the sleep cycle rate is configured to be equal to the quotient of the sampling rate divided by the buffering rate, and

wherein the buffering rate and the sampling rate are configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

10. The device of claim 9, wherein the buffering rate and the sampling rate are configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the sampled signal or less than a lower bound frequency of the target frequency band of the sampled signal.

11. The device of claim 1,

wherein the analog-to-digital converter is a first analog-to-digital converter, wherein the input signal is a first input signal, wherein the sampled signal is a first sampled signal,

wherein the device further comprises a second analog-to-digital converter configured to sample a second input signal at a sampling rate to produce a second sampled signal,

wherein the processor is further configured to buffer the second sampled signal at a buffering rate, the buffering rate being indicative of a number of data samples to buffer per invocation of a processing algorithm,

wherein the processor is further configured to invoke instances of the processing algorithm at a rate equal to a quotient of the sampling rate divided by the buffering rate to process the second sampled signal,

wherein the sleep cycle rate is configured to be equal to the quotient of the sampling rate divided by the buffering rate, and

wherein the buffering rate and the sampling rate are configured such that the spectral interference caused by the sleep cycle rate occurs in the first sampled signal at the one or more frequencies that are outside of the target frequency band of the first sampled signal.

12. The device of claim 11, wherein the buffering rate and the sampling rate are configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the first sampled signal or less than a lower bound frequency of the target frequency band of the first sampled signal.

13. The device of claim 1,

wherein the processor is further configured to invoke instances of a processing algorithm at an algorithm processing rate to process the sampled signal,

wherein the processor is further configured to, for each of the instances of the processing algorithm that are invoked, execute the respective instance of the processing algorithm during a number of separate time intervals, each of the separate time intervals being separated from adjacent time intervals by a time interval where the respective processing algorithm is not executed, the number of separate time intervals being determined by an algorithm subdivision factor,

wherein the sleep cycle rate is configured to be equal to a product of an algorithm processing rate and the algorithm subdivision factor, and

wherein the algorithm processing rate and the algorithm subdivision factor are configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

14. The device of claim 13, wherein the algorithm processing rate and the algorithm subdivision factor are configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the sampled signal or less than a lower bound frequency of the target frequency band of the sampled signal.

15. The device of claim 13,

wherein the analog-to-digital converter is further configured to sample the input signal at a sampling rate to produce the sampled signal,

wherein the processor is further configured to buffer the sampled signal at a buffering rate, the buffering rate being indicative of a number of data samples to buffer per invocation of the processing algorithm,

wherein the algorithm processing rate is equal to a quotient of the sampling rate divided by the buffering rate, and

wherein the sampling rate, the buffering rate and the algorithm subdivision factor are configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

16. The device of claim 1,

wherein the analog-to-digital converter is a first analog-to-digital converter, wherein the input signal is a first input signal, wherein the sampled signal is a first sampled signal,

wherein the device further comprises a second analog-to-digital converter configured to sample a second input signal to produce a second sampled signal,

wherein the processor is further configured to invoke instances of a processing algorithm at an algorithm processing rate to process the second sampled signal,

wherein the processor is further configured to, for each of the instances of the processing algorithm that are invoked, execute the respective instance of the processing algorithm during a number of separate time intervals, each of the separate time intervals being separated from adjacent time intervals by a time interval where the respective processing algorithm is not executed, the number of separate time intervals being determined by an algorithm subdivision factor,

wherein the sleep cycle rate is configured to be equal to a product of the algorithm processing rate and the algorithm subdivision factor, and

wherein the algorithm processing rate and the algorithm subdivision factor are configured such that the spectral interference caused by the sleep cycle rate occurs in the first sampled signal at the one or more frequencies that are outside of the target frequency band of the first sampled signal.

17. The device of claim 16, wherein the algorithm processing rate and the algorithm subdivision factor are configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the first sampled signal or less than a lower bound frequency of the target frequency band of the first sampled signal.

18. The device of claim 16,

wherein the second analog-to-digital converter is further configured to sample the second input signal at a sampling rate to produce the second sampled signal,

wherein the processor is further configured to buffer the second sampled signal at a buffering rate, the buffering rate being indicative of a number of data samples to buffer per invocation of the processing algorithm,

wherein the algorithm processing rate is equal to a quotient of the sampling rate divided by the buffering rate, and

wherein the sampling rate, the buffering rate and the algorithm subdivision factor are configured such that the spectral interference caused by the sleep cycle rate occurs in the first sampled signal at the one or more frequencies that are outside of the target frequency band of the first sampled signal.

19. The device of claim 1, wherein the physiological signal is brain signal and the target frequency band is one of an alpha, beta, gamma or fast ripple frequency band of the brain signal.

20. The device of claim 19, wherein the brain signal comprises at least one of an electroencephalogram (EEG) signal, an electrocorticogram (ECoG) signal, a local field potential (LFP) signal, or a single cell action potential signal.

21. The device of claim 1, wherein the processor is further configured to determine at least one of a power level of the target frequency band in the sampled signal and a power fluctuation of the target frequency band in the sampled signal.

22. The device of claim 1, wherein the processor is further configured to analyze the target frequency band of the sampled signal.

23. The device of claim 1, wherein the target frequency band of the sampled signal is a target frequency band to be analyzed during post-processing of the sampled signal.

24. The device of claim 1, wherein the power source, the power distribution network, the analog-to-digital converter, and the processor are included in an implantable medical device.

25. A method for monitoring signals comprising:

sampling, with an analog-to-digital converter, an input signal to produce a sampled signal; and

cycling a processor between an algorithm processing mode and a sleep mode based on a sleep cycle rate,

wherein the analog-to-digital converter and the processor are both electrically coupled to a power distribution network that is electrically coupled to a power source,

wherein the sleep cycle rate causes spectral interference to propagate through the power distribution network and into the sampled signal via the analog-to-digital converter, and

wherein the sleep cycle rate further causes the spectral interference that is generated due to the sleep cycle rate to occur in the sampled signal at one or more frequencies that are outside of a target frequency band of the sampled signal.

26. The method of claim 25, wherein the sleep cycle rate is configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

27. The method of claim 26, wherein the sleep cycle rate is configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the sampled signal.

28. The method of claim 26, wherein the sleep cycle rate is configured such that the sleep cycle rate is less than a lower bound frequency of the target frequency band of the sampled signal.

29. The method of claim 25, further comprising:

invoking, with the processor, instances of a processing algorithm at an algorithm processing rate to process the sampled signal,

wherein the sleep cycle rate is configured to be equal to the algorithm processing rate, and

wherein the algorithm processing rate is configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

30. The method of claim 29, wherein the algorithm processing rate is configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the sampled signal or less than a lower bound frequency of the target frequency band of the sampled signal.

31. The method of claim 25,

wherein the analog-to-digital converter is a first analog-to-digital converter, wherein the input signal is a first input signal, wherein the sampled signal is a first sampled signal,

wherein the method further comprises:

sampling, with a second analog-to-digital converter, a second input signal to produce a second sampled signal,

invoking, with the processor, instances of a processing algorithm at an algorithm processing rate to process the second sampled signal,

wherein the sleep cycle rate is configured to be equal to the algorithm processing rate, and

wherein the algorithm processing rate is configured such that the spectral interference caused by the sleep cycle rate occurs in the first sampled signal at the one or more frequencies that are outside of the target frequency band of the first sampled signal.

32. The method of claim 31, wherein the algorithm processing rate is configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the first sampled signal or less than a lower bound frequency of the target frequency band of the first sampled signal.

33. The method of claim 25, further comprising:

sampling, with the analog-to-digital converter, the input signal at a sampling rate;

buffering, with the processor, the sampled signal at a buffering rate, the buffering rate being indicative of a number of data samples to buffer per invocation of a processing algorithm;

invoking, with the processor, instances of the processing algorithm at a rate equal to a quotient of the sampling rate divided by the buffering rate to process the sampled signal,

wherein the sleep cycle rate is configured to be equal to the quotient of the sampling rate divided by the buffering rate, and

wherein the buffering rate and the sampling rate are configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

34. The method of claim 33, wherein the buffering rate and the sampling rate are configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the sampled signal or less than a lower bound frequency of the target frequency band of the sampled signal.

35. The method of claim 25,

wherein the analog-to-digital converter is a first analog-to-digital converter, wherein the input signal is a first input signal, wherein the sampled signal is a first sampled signal,

wherein the method further comprises:

sampling, with a second analog-to-digital converter, a second input signal at a sampling rate to produce a second sampled signal;

buffering, with the processor, the second sampled signal at a buffering rate, the buffering rate being indicative of a number of data samples to buffer per invocation of a processing algorithm; and

invoking, with the processor, instances of the processing algorithm at a rate equal to a quotient of the sampling rate divided by the buffering rate to process the second sampled signal,

wherein the sleep cycle rate is configured to be equal to the quotient of the sampling rate divided by the buffering rate, and

wherein the buffering rate and the sampling rate are configured such that the spectral interference caused by the sleep cycle rate occurs in the first sampled signal at the one or more frequencies that are outside of the target frequency band of the first sampled signal.

36. The method of claim 35, wherein the buffering rate and the sampling rate are configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the first sampled signal or less than a lower bound frequency of the target frequency band of the first sampled signal.

37. The method of claim 25, further comprising:

invoking, with the processor, instances of a processing algorithm at an algorithm processing rate to process the sampled signal,

for each of the instances of the processing algorithm that are invoked, executing, with the processor, the respective instance of the processing algorithm during a number of separate time intervals, each of the separate time intervals being separated from adjacent time intervals by a time interval where the respective processing algorithm is not executed, the number of separate time intervals being determined by an algorithm subdivision factor,

wherein the sleep cycle rate is configured to be equal to a product of an algorithm processing rate and the algorithm subdivision factor, and

wherein the algorithm processing rate and the algorithm subdivision factor are configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

38. The method of claim 37, wherein the algorithm processing rate and the algorithm subdivision factor are configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the sampled signal or less than a lower bound frequency of the target frequency band of the sampled signal.

39. The method of claim 37,

wherein sampling, with the analog-to-digital converter, the input signal comprises sampling the input signal at a sampling rate to produce the sampled signal,

wherein the method further comprises buffering, with the processor, the sampled signal at a buffering rate, the buffering rate being indicative of a number of data samples to buffer per invocation of the processing algorithm,

wherein the algorithm processing rate is equal to a quotient of the sampling rate divided by the buffering rate,

wherein the sampling rate, the buffering rate and the algorithm subdivision factor are configured such that the spectral interference caused by the sleep cycle rate occurs in the sampled signal at the one or more frequencies that are outside of the target frequency band of the sampled signal.

40. The method of claim 25,

wherein the analog-to-digital converter is a first analog-to-digital converter, wherein the input signal is a first input signal, wherein the sampled signal is a first sampled signal,

wherein the method further comprises:

sampling, with a second analog-to-digital converter, a second input signal to produce a second sampled signal;

invoking, with the processor, instances of a processing algorithm at an algorithm processing rate to process the second sampled signal;

for each of the instances of the processing algorithm that are invoked, executing, with the processor, the respective instance of the processing algorithm during a number of separate time intervals, each of the separate time intervals being separated from adjacent time intervals by a time interval where the respective processing algorithm is not executed, the number of separate time intervals being determined by an algorithm subdivision factor,

wherein the sleep cycle rate is configured to be equal to a product of the algorithm processing rate and the algorithm subdivision factor, and

wherein the algorithm processing rate and the algorithm subdivision factor are configured such that the spectral interference caused by the sleep cycle rate occurs in the first sampled signal at the one or more frequencies that are outside of the target frequency band of the first sampled signal.

41. The method of claim 40, wherein the algorithm processing rate and the algorithm subdivision factor are configured such that the sleep cycle rate is greater than an upper bound frequency of the target frequency band of the first sampled signal or less than a lower bound frequency of the target frequency band of the first sampled signal.

42. The method of claim 40,

wherein sampling, with the second analog-to-digital converter, the second input signal comprises sampling the second input signal at a sampling rate to produce the second sampled signal,

wherein the method further comprises buffering the second sampled signal at a buffering rate, the buffering rate being indicative of a number of data samples to buffer per invocation of the processing algorithm,

wherein the algorithm processing rate is equal to a quotient of the sampling rate divided by the buffering rate, and

wherein the sampling rate, the buffering rate and the algorithm subdivision factor are configured such that the spectral interference caused by the sleep cycle rate occurs in the first sampled signal at the one or more frequencies that are outside of the target frequency band of the first sampled signal.

43. The method of claim 25, wherein the physiological signal is brain signal and the target frequency band is one of an alpha, beta, gamma or fast ripple frequency band of the brain signal.

44. The method of claim 43, wherein the brain signal comprises at least one of an electroencephalogram (EEG) signal, an electrocorticogram (ECoG) signal, a local field potential (LFP) signal, or a single cell action potential signal.

45. The method of claim 25, further comprising determining, with the processor, at least one of a power level of the target frequency band in the sampled signal and a power fluctuation of the target frequency band in the sampled signal.

46. The method of claim 25, further comprising analyzing, with the processor, the target frequency band of the sampled signal.

47. The method of claim 25, wherein the target frequency band of the sampled signal is a target frequency band to be analyzed during post-processing of the sampled signal.

48. The method of claim 25, wherein the power source, the power distribution network, the analog-to-digital converter, and the processor are included in an implantable medical device.

49. An apparatus for monitoring signals comprising:

means for sampling an input signal to produce a sampled signal; and

means for cycling between an algorithm processing mode and a sleep mode based on a sleep cycle rate,

wherein the means for sampling and the means for cycling are electrically coupled to a power distribution network that is electrically coupled to a power source,

wherein the sleep cycle rate causes spectral interference to propagate through the power distribution network and into the sampled signal, and

wherein the sleep cycle rate further causes the spectral interference that is generated due to the sleep cycle rate to occur in the sampled signal at one or more frequencies that are outside of a target frequency band of the sampled signal.