Method and apparatus for removing baseline wander from an ECG signal
First Claim
1. A method for removing baseline wander from an ECG signal comprising the steps of:
- applying a real-time ECG signal to a first nonlinear filter which produces filtered-signal data;
storing the filtered-signal data;
applying blocks of the stored data in time-reversed order to a second nonlinear filter substantially identical to the first nonlinear filter thereby producing reverse-filtered blocks; and
displaying each reverse-filtered block in chronological order.
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Accused Products
Abstract
A method and apparatus for removing baseline wander in which an ECG waveform is continuously sampled at 500 samples per second. The digitized data is continuously filtered by an infinite-impulse response (IIR) filter implemented on a first microprocessor. The data is stored in a buffer from which it is read in reverse chronological order in overlapping 3 second blocks. Each block is applied to the input of a second IIR filter which is implemented on a second microprocessor with substantially the same code as the first IIR filter. The first 1.5 seconds of each reverse-filtered block is disregarded to permit the output of the filter to settle. The retained data is stored in a queue from which it is read and displayed on a monitor or printed with baseline wander removed.
37 Citations
18 Claims
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1. A method for removing baseline wander from an ECG signal comprising the steps of:
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applying a real-time ECG signal to a first nonlinear filter which produces filtered-signal data; storing the filtered-signal data; applying blocks of the stored data in time-reversed order to a second nonlinear filter substantially identical to the first nonlinear filter thereby producing reverse-filtered blocks; and displaying each reverse-filtered block in chronological order. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for removing baseline wander from an ECG signal comprising the steps of:
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continuously filtering a real-time ECG signal thereby producing filtered ECG data; dividing the filtered data into predetermined time periods; reverse filtering the data in each time period; and arranging the reverse-filtered data in chronological order to form a continuous ECG signal. - View Dependent Claims (8, 9, 10, 11)
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12. Apparatus for removing baseline wander from an ECG signal comprising:
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a first filter for continuously filtering a real-time ECG signal thereby producing filtered ECG data; means for dividing the filtered data into predetermined time periods; means for reverse filtering the data in each time period; and means for arranging the reverse-filtered data in chronological order to form a continuous ECG signal. - View Dependent Claims (13, 14, 15, 16)
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17. A method for removing baseline wander from an ECG signal comprising the steps of:
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filtering a real-time ECG signal according to a predetermined filter characteristic equation having a non-linear phase response to produce filtered-signal data; storing the filtered-signal data; filtering blocks of the stored data in time-reversed order according to the said filter characteristic equation thereby producing reverse-filtered blocks; and displaying each reverse-filtered block in chronological order. - View Dependent Claims (18)
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Specification