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1. (WO1998052463) ECG NOISE DETECTION SYSTEM
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ECG NOISE DETECTION SYSTEM

CLAIMS

1. A device for detecting and removing noise from an ECG signal comprising:
an ECG signal input for receiving an ECG signal from a patient;
a baseline wander filter connected to said ECG input for removing baseline wander from said ECG signal;
an adaptive line noise canceler for removing line noise from said ECG signal wherein said adaptive line noise canceler adjusts to said ECG signal from said ECG input to remove varying amounts of said line noise from said ECG signal; and
at least one noise detector to signal to the operator of the device that noise exists in said ECG signal from said ECG input.

2. The device of claim 1 wherein said adaptive line noise canceler removes said line noise from said ECG signal from said ECG input by producing a sinusoidal wave that matches the component of said ECG signal which is induced by a local power line.

3. The device of claim 1 wherein said adaptive noise canceler includes a quadrature sine wave generator therein.

4. The device of claim 1 wherein said adaptive line noise canceler includes a frequency tripler to remove the third harmonic of said noise from said ECG signal.

5. The device of claim 1 wherein said baseline wander filter includes a low pass filter for attenuating the components of said ECG signal above a preselected cutoff frequency and for passing the components of said ECG signal below said preselected cutoff frequency and a delay member for delaying said ECG signal for time approximately equal to the time said low pass filter requires to pass the components of said ECG signal and a summer for subtracting the components of said ECG signal which are passed through said low pass filter from said ECG signal components from said delay member.

6. The device of claim 5 further including a baseline wander detector which compares an output from said low pass filter with a predetermined value to determine if baseline wander is present in said ECG signal.

7. The device of claim 1 further including an ECG gate signal which has a portion of said ECG signal blanked from a point in time just prior to the onset of the QRS portion of said ECG signal and ending at a point in time just after the end of the QRS portion.

8. The device of claim 7 wherein said ECG gate signal is applied to said adaptive line noise canceler.

9. The device of claim 8 wherein said ECG gate signal is applied to a pulse stretcher to increase the duration of said ECG gate signal to operate a switch prior to the application of said ECG signal to said at least one noise detector.

10. A device for detecting and removing noise from an ECG signal comprising:
an ECG signal input for receiving an ECG signal from a patient;
an ECG gate signal which has a portion of said

ECG signal blanked from a point in time just prior to the onset of the QRS portion of said ECG signal and ending at a point in time just after the end of the QRS portion; and an adaptive line noise canceler for removing line noise from said ECG signal wherein said adaptive line noise canceler receives said ECG signal and said ECG gate signal adjusts to changes in said ECG signal from said ECG input to remove varying amounts of said line noise from said ECG signal.

11. The device of claim 10 wherein said adaptive line noise canceler removes said line noise from said ECG signal from said ECG input by producing a sinusoidal wave that matches the component of said ECG signal which is induced by said line noise.

12. The device of claim 10 wherein said adaptive noise canceler includes a quadrature sine wave generator therein.

13. The device of claim 10 wherein said adaptive line noise canceler includes a frequency tripler to remove the third harmonic of said line noise from said ECG signal.

14. The device of claim 10 further including a low pass filter for attenuating the components of said ECG signal above a preselected cutoff frequency and for passing the components of said ECG signal below said preselected cutoff frequency and a delay member for delaying said ECG signal for a time approximately equal to the time said low pass filter requires to pass the components of said ECG signal and a summer for subtracting the components of said ECG signal which are passed through said low pass filter from said ECG signal components from said delay member for processing said ECG signal prior to the receipt of said ECG signal by said adaptive line noise canceler.

15. The device of claim 10 wherein said adaptive line noise canceler includes a switch and said ECG gate signal is applied thereto to prevent said ECG signal from causing distortion in said adaptive line noise canceler.

16. The device of claim 10 wherein said device further includes at least one high pass filter therein to remove components of said ECG signal below a preselected cutoff frequency and for passing the components of said ECG signal above said preselected cutoff frequency.

17. The device of claim 10 further including at least one noise detector to signal to the operator of the device that noise exists in said ECG signal from said ECG input.

18. The device of claim 10 wherein said adaptive line noise canceler is a quadrature detector.

19. A device for detecting and removing noise from an ECG signal comprising:
an ECG signal input for receiving an ECG signal from a patient;
means, connected to said input for attenuating and delaying the frequency components of said ECG signal for removing baseline wander from said ECG signal;
means, connected to said means for removing baseline wander for removing line noise from said ECG signal wherein said means adjusts to said ECG signal from said ECG input to remove varying amounts of said line noise from said ECG signal; and
means, connected to said ECG signal to signal to the operator of the device that noise exists in said ECG signal from said ECG input.

20. A device for detecting and removing noise from an ECG signal comprising:
an ECG signal input for receiving an ECG signal from a patient;

an ECG gate signal which has a portion of said

ECG signal blanked from a point in time just prior to the onset of the QRS portion of said ECG signal and ending at a point in time just after the end of the QRS portion;
a filter connected to said ECG input for removing contamination from said ECG signal; and
an adaptive line noise canceler for removing line noise from said ECG signal wherein said adaptive line noise canceler receives said ECG signal and said ECG gate signal and adjusts to said ECG signal from said ECG input to remove varying amounts of said line noise from said ECG signal.

21. A device for detecting and removing wide band noise from an ECG signal comprising:
an ECG signal input for receiving an ECG signal from a patient;
an ECG gate signal which has a portion of said

ECG signal blanked from a point in time just prior to the onset of the QRS portion of said ECG signal and ending at a point in time just after the end of the QRS portion;
a high pass filter which filters said ECG signal and said ECG gate signal to form a high pass filtered ECG signal with the QRS portion removed; and
a wideband noise detector which processes said filtered ECG signal.

22. The device of claim 21 wherein said device further includes an adaptive line noise canceler which removes line noise from said ECG signal prior to passing said ECG signal through said high pass filter.

23. The device of claim 21 wherein said device further includes a switch which is responsive to said ECG gate signal to prevent the QRS portion of said ECG signal from passing through said wideband noise detector.

24. The device of claim 21 wherein said device further includes a line noise filter to remove line noise from said ECG signal prior to the passage of said ECG signal through said wideband noise detector.

25. The device of claim 21 wherein said device further includes a baseline wander filter to remove baseline wander from said ECG signal prior to the passage of said ECG signal through said wideband noise detector.

26. A device for detecting and removing noise from an ECG signal comprising:
an ECG signal input for receiving an ECG signal from a patient;
an ECG gate signal which has a portion of said

ECG signal blanked from a point in time just prior to the onset of the QRS portion of said ECG signal and ending at a point in time just after the end of the QRS portion;
means, connected to said input for attenuating and delaying the frequency components of said ECG signal to filter said ECG signal;
switch means for opening and closing a switch in response to said ECG gate signal to allow for the selective passage of said ECG signal therethrough; and
means, connected to said means for filtering for removing line noise from said ECG signal wherein said means receives said ECG signal following said switch means and measures the wideband noise of said ECG signal which passes beyond said switch.

27. A device for detecting and removing noise from an ECG signal comprising:
an ECG signal input for receiving an ECG signal from a patient;
an ECG gate signal which has a portion of said

ECG signal blanked from a point in time just prior to the onset of the QRS portion of said ECG signal and ending at a point in time just after the end of the QRS portion;
a switch member connected to said ECG input for allowing said ECG signal to pass therethrough in response to said ECG gate signal; and
a wideband noise detector for measuring wideband noise from said ECG signal wherein said wideband noise detector receives said ECG signal through said switch member.

28. The device of claim 27 further including a high pass filter to allow the high frequency portion of said ECG signal to pass therethrough and to said wideband noise detector.

29. The device of claim 27 further including an adaptive line noise canceler therein having a high pass filter therein to filter said ECG signal prior to the passage of said ECG signal to said wideband noise detector.

30. A method for detecting and removing noise from an ECG signal comprising:
providing an ECG signal input for receiving an ECG signal from a patient;
providing the ECG signal to a baseline wander filter having an ECG input thereon and processing the ECG signal to remove baseline wander from the ECG signal;
providing the processed ECG signal to an adaptive line noise canceler for removing line noise from the processed ECG signal and adjusting the adaptive line noise canceler to the processed ECG signal to remove varying amounts of line noise from the processed ECG signal; and
providing at least one noise detector to signal to the operator of the device that noise exists in the ECG signal.

31. A method for detecting and removing noise from an ECG signal comprising:
providing an ECG signal input for receiving an ECG signal from a patient;
providing an ECG gate signal which has a portion of said ECG signal blanked from a point in time just prior to the onset of the QRS portion of said ECG signal and ending at a point in time just after the end of the QRS portion;
providing the ECG signal and ECG gate signal to an adaptive line noise canceler for removing line noise from the ECG signal and adjusting the adaptive line noise canceler to changes in the ECG signal to remove varying amounts of line noise from the processed ECG signal.

32. The method of claim 31 wherein at least one noise detector is provided and the at least one noise detector activates at least one filter to remove the detected noise from the ECG signal.

33. The method of claim 31 wherein the gated ECG signal which is presented to the adaptive line noise canceler in addition to the ECG signal to improve detection of the line noise by removing the QRS portion of the ECG signal during the detection of line noise.

34. A method for detecting and removing noise from an ECG signal comprising:
providing an ECG signal input for receiving an ECG signal from a patient;
providing the ECG signal to a filter having an

ECG input thereon and processing the ECG signal to remove contamination from the ECG signal;
providing the processed ECG signal to an adaptive line noise canceler for removing line noise from the processed ECG signal and adjusting the adaptive line noise canceler to the processed ECG signal to remove varying amounts of line noise from the processed ECG signal.

35. A method for detecting and removing noise from an ECG signal comprising:
providing an ECG signal input for receiving an ECG signal from a patient;
providing an ECG gate signal which has a portion of said ECG signal blanked from a point in time just prior to the onset of the QRS portion of said ECG signal and ending at a point in time just after the end of the QRS portion;
providing the ECG signal and ECG gate signal to a switch member which is selectively opened and closed in response to said ECG gate signal to selectively allow said ECG signal to pass therethrough;
providing a wideband noise detector to measure the high frequency noise in the ECG signal following the switch member.

36. A method for detecting and removing noise from an ECG signal comprising:
providing an ECG signal input for receiving an ECG signal from a patient;
providing the ECG signal to a filter having an

ECG input thereon and processing the ECG signal to remove contamination from the ECG signal;
providing the processed ECG signal to an adaptive line noise canceler for removing line noise from the processed ECG signal and adjusting the adaptive line noise canceler to the processed ECG signal to remove varying amounts of line noise from the processed ECG signal to produce a further processed ECG signal; and
providing the further processed ECG signal to a wideband noise detector to provide and estimate of the amount of high frequency energy present in the ECG signal.