Method and device for analyzing a periodic or semi-periodic signal
First Claim
1. A device for reducing noise in signals having successive substantially repetitive portions, comprising:
- an iterative averager operative to superimpose and average said substantially repetitive portions to produce a running average thereof,an iteration ender comprising a noise analyzer for determining a noise level in said running average and ending operation of said iterative averager when a noise level reaches a predetermined level,an aligner for aligning at least some of said substantially repetitive portions one with another,wherein said signal comprisesfirst frequency and second frequency components and said aligner comprises a first frequency correlated band pass filter and a second frequency correlated band pass filter to extract respective first and second frequency components, thereby to use said first frequency components to locate an alignment point in successive portions and to use said alignment point to align said second frequency components.
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Accused Products
Abstract
A device for reducing noise in signals having successive substantially repetitive portions, comprising: an iterative averager operative to superimpose and average said substantially repetitive portions to produce a running average thereof, and an iteration ender comprising a noise analyzer for determining a noise level in said running average and ending operation of said iterative averager when said noise level reaches a predetermined level. Also, a method of obtaining an indication of ischemia in a patient using an ECG signal therefrom, the method comprising: extracting an ECG signal over a duration, extracting from said ECG signal a series of QRS complexes over said duration, extracting high frequency components of said QRS complexes, analyzing said high frequency components over said duration for at least one of a predetermined quality, and inferring from said predetermined quality an indication of ischemia.
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Citations
19 Claims
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1. A device for reducing noise in signals having successive substantially repetitive portions, comprising:
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an iterative averager operative to superimpose and average said substantially repetitive portions to produce a running average thereof, an iteration ender comprising a noise analyzer for determining a noise level in said running average and ending operation of said iterative averager when a noise level reaches a predetermined level, an aligner for aligning at least some of said substantially repetitive portions one with another, wherein said signal comprises first frequency and second frequency components and said aligner comprises a first frequency correlated band pass filter and a second frequency correlated band pass filter to extract respective first and second frequency components, thereby to use said first frequency components to locate an alignment point in successive portions and to use said alignment point to align said second frequency components. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A device for reducing noise in signals having successive substantially repetitive portions, comprising:
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a repetitive portion selector for selecting repetitive portions for passing to an iterative averager, the repetitive portion selector comprising; a reference portion store for storing said reference portion, a first cross correlator for computing cross correlation between current repetitive portion and said reference portion, a comparator for comparing a result of said cross-correlation with a predetermined threshold to produce a comparison output, said iterative averager operative to superimpose and average said substantially repetitive portions to produce running average thereof, an iteration ender comprising a noise analyzer for determining a noise level in said running average and ending operation of said iterative averager when noise level reaches a predetermined level, an aligner for aligning at least some of substantially repetitive portions one with another, a reference portion determiner, wherein said reference portion determiner comprising, a first store for storing a first set of repetitive portions from said signal, a second store for storing a second set of repetitive portions from said signal, a second cross correlator for cross-correlating repetitive portions from said second set in turn with repetitive portions from said first set to produce a plurality of cross-correlation results for respective repetitive portions in said second set, and a reference selector for selecting one of said repetitive portions in said second set as a reference portion in accordance with its respective cross-correlation results. - View Dependent Claims (17, 18, 19)
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Specification