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US5564428A
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Method and apparatus for enhancing the signal-to-noise ratio of ECG signals
Assignee: Siemens AG
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Filing: 1994-07-07
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Granted: 1996-10-15
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Expires: 2014-07-07
Abstract
Abstract In a method for enhancing the signal-to-noise ratio of ECG signals, A/D-converted signals from a number of cardiac cycles are time-synchronized to form a signal ensemble, and the correlation between the signals in the ensemble is determined in time intervals, comprising at least two samples, during at least a part of the cardiac cycles. A device for enhancing the signal-to-noise ratio of ECG signals, includes circuitry for recording, A/D-converting and other processing of the ECG signals. A synchronization unit is arranged to time-synchronize the signals from a plurality of cardiac cycles to form a signal ensemble, and a calculator unit controlled by a window unit determines the correlation between the signals in the ensemble in time intervals, comprising at least two samples, during at least a part of the cardiac cycles.
Inventors
- 👤 Leif Soernmo
- 👤 Thomas Ohlsson
- 👤 Roozbeh Atarius
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 23:06
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/24; A61B5/30; A61B5/307; A61B5/308; A61B5/316; A61B5/318; A61B5/346; A61B5/72; A61B5/7203; A61B5/7235; A61B5/7246
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
88 words
A method for enhancing the signal-to-noise ratio of ECG signals comprising the steps of: obtaining analog ECG signals from a plurality of cardiac cycles; converting the analog ECG signals into digital ECG signals; time-synchronizing the digital ECG signals from the respective cardiac cycles to form a signal ensemble; determining a correlation between the ECG signals in said ensemble in time intervals comprising at least two samples during at least a part of said cardiac cycles; and employing said correlation to enhance the signal-to-noise ratio of the ECG signals.
Claim 2
Independent Claim
88 words
A method for enhancing the signal-to-noise ratio of ECG signals comprising the steps of: obtaining analog ECG signals from a plurality of cardiac cycles; converting the analog ECG signals into digital ECG signals; time-synchronizing the digital ECG signals from the respective cardiac cycles to form a signal ensemble; determining a correlation between the ECG signals in said ensemble in time intervals comprising at least two samples during at least a part of said cardiac cycles; and employing said correlation to enhance the signal-to-noise ratio of the ECG signals.
Claim 3
Dependent Claim
51 words
A method as claimed in claim 1 wherein the step of determining the correlation between the signals comprises determining a set of weightings expressing said correlation between the signals, and wherein the step of enhancing said signal-to-noise ratio comprises filtering said ECG signals with a filter characteristic determined by said weightings.
Claim 4
Dependent Claim
20 words
A method as claimed in claim 1 further comprising forming an average value of said signals in said signal ensemble.
Claim 5
Dependent Claim
35 words
A method as claimed in claim 1 wherein the step of determining the correlation between the signals in said ensemble comprises determining the correlation between the signals in said ensemble in successive, overlapping time intervals.
Claim 6
Dependent Claim
49 words
A method as claimed in claim 4 wherein the step of determining the correlation between the signals in said ensemble in successive, overlapping time intervals produces weightings, and wherein the step of enhancing said signal-to-noise ratio comprises filtering said ECG signals with a filter characteristic determined by said weightings.
Claim 7
Dependent Claim
29 words
A method as claimed in claim 5 wherein the step of filtering the ECG signals comprises filtering the ECG signals with a time-variable filter characteristic determined by said weightings.
Claim 8
Independent Claim
116 words
An apparatus for enhancing the signal-to-noise ratio of analog ECG signals, comprising: means for recording analog ECG signals from a subject from a plurality of cardiac cycles; means for converting the analog ECG signals into digital ECG signals; means for time synchronizing the digital ECG signals from the respective cardiac cycles to form a signal ensemble; means for setting a time window comprising at least two samples of said digital ECG signals; means for correlating the digital ECG signals in said ensemble within said time window during at least a part of said cardiac cycles; and means for enhancing the signal-to-noise ratio of the ECG signals dependent on the correlation between the signals in the ensemble.
Claim 9
Independent Claim
116 words
An apparatus for enhancing the signal-to-noise ratio of analog ECG signals, comprising: means for recording analog ECG signals from a subject from a plurality of cardiac cycles; means for converting the analog ECG signals into digital ECG signals; means for time synchronizing the digital ECG signals from the respective cardiac cycles to form a signal ensemble; means for setting a time window comprising at least two samples of said digital ECG signals; means for correlating the digital ECG signals in said ensemble within said time window during at least a part of said cardiac cycles; and means for enhancing the signal-to-noise ratio of the ECG signals dependent on the correlation between the signals in the ensemble.
Claim 10
Dependent Claim
37 words
An apparatus as claimed in claim 7 wherein said means for correlating comprise means for producing a weighting function and wherein said means for enhancing comprises a filter having a filter characteristic determined by said weighting function.
Claim 11
Dependent Claim
28 words
An apparatus as claimed in claim 7 further comprising averaging means, controlled by said means for time-synchronizing, for forming an average value of said signals in said ensemble.
Claim 12
Dependent Claim
28 words
An apparatus as claimed in claim 7 further comprising averaging means, controlled by said means for setting a time window, for averaging said signals in said signal ensemble.
Claim 13
Dependent Claim
35 words
An apparatus as claimed in claim 7 wherein said means for setting a time window comprises means for controlling said means for correlating for determining the correlation of said ensemble in successive, overlapping time intervals.
Claim 14
Dependent Claim
17 words
An apparatus as claimed in claim 7 wherein said means for correlating comprises a maximum likelihood estimator.
Claim 15
Independent Claim
120 words
An apparatus for enhancing the signal-to-noise ratio of analog ECG signals comprising: means for recording analog ECG signals over a plurality of cardiac cycles of a subject; means for converting the analog ECG signals into digital ECG signals; means for time-synchronizing the digital ECG signals from the respective cardiac cycles in said plurality of cardiac cycles to form a signal ensemble; means for setting a time window comprising at least two samples of said digital ECG signals; means for determining the correlation between the digital ECG signals in said ensemble in said time interval; and means for filtering said ECG signals, for enhancing the signal-to-noise ratio, with a filter characteristic dependent on the correlation between said signals in said ensemble.
Claim 16
Independent Claim
120 words
An apparatus for enhancing the signal-to-noise ratio of analog ECG signals comprising: means for recording analog ECG signals over a plurality of cardiac cycles of a subject; means for converting the analog ECG signals into digital ECG signals; means for time-synchronizing the digital ECG signals from the respective cardiac cycles in said plurality of cardiac cycles to form a signal ensemble; means for setting a time window comprising at least two samples of said digital ECG signals; means for determining the correlation between the digital ECG signals in said ensemble in said time interval; and means for filtering said ECG signals, for enhancing the signal-to-noise ratio, with a filter characteristic dependent on the correlation between said signals in said ensemble.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-10-15 | 2000-04-15 | 2000-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-15 | 2004-04-15 | 2004-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-15 | 2008-04-15 | 2008-10-15 | $7700.00 | Window Closed / Lapsed |