Impedance measurement system
First Claim
1. A method of monitoring a condition of a plurality of electrodes used in the measurement of a biological signal, the method comprising:
- applying a plurality of test signals to the plurality of electrodes, wherein applying the plurality of test signals to the plurality of electrodes comprises applying a first test signal having a first frequency to at least one of the plurality of electrodes and concurrently applying a second test signal having a second frequency different from the first frequency to at least one of the plurality of electrodes at a same time during which the first test signal is applied, wherein both the first frequency and the second frequency are below a frequency range associated with the biological signal;
capturing the biological signal while applying the plurality of test signals and generating an output signal that includes both the measured biological signal and the plurality of test signals;
retrieving an output amplitude for each of the plurality of test signals from the output signal, retrieving the output amplitude for each of the plurality of test signals comprising;
determining the output amplitude for the first test signal by measuring a first amplitude of a first signal component of the output signal corresponding to the first frequency; and
determining the output amplitude for the second test signal by measuring a second amplitude of a second signal component of the output signal corresponding to the second frequency;
calculating an estimated impedance for each of the plurality of electrodes based on the retrieved output amplitudes of the plurality of test signals;
generating a quantitative indication of the condition of the plurality of electrodes based on the calculated estimated impedances for the plurality of electrodes; and
providing the quantitative indication of the condition of the plurality of electrodes to a user.
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Accused Products
Abstract
Systems and methods for monitoring the condition of electrodes used in biological signal measurement are provided. One method includes applying a first test signal having a first frequency to at least one of a plurality of electrodes and applying a second test signal having a second frequency to at least one of the plurality of electrodes. Both frequencies are below a frequency range associated with the biological signal. The method further includes capturing the biological signal while applying the plurality of test signals and generating an output signal that includes both the measured biological signal and the plurality of test signals. The method further includes retrieving an output amplitude for each of the plurality of test signals from the output signal and calculating an estimated impedance for each of the plurality of electrodes based on the retrieved output amplitudes of the plurality of test signals.
40 Citations
23 Claims
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1. A method of monitoring a condition of a plurality of electrodes used in the measurement of a biological signal, the method comprising:
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applying a plurality of test signals to the plurality of electrodes, wherein applying the plurality of test signals to the plurality of electrodes comprises applying a first test signal having a first frequency to at least one of the plurality of electrodes and concurrently applying a second test signal having a second frequency different from the first frequency to at least one of the plurality of electrodes at a same time during which the first test signal is applied, wherein both the first frequency and the second frequency are below a frequency range associated with the biological signal; capturing the biological signal while applying the plurality of test signals and generating an output signal that includes both the measured biological signal and the plurality of test signals; retrieving an output amplitude for each of the plurality of test signals from the output signal, retrieving the output amplitude for each of the plurality of test signals comprising; determining the output amplitude for the first test signal by measuring a first amplitude of a first signal component of the output signal corresponding to the first frequency; and determining the output amplitude for the second test signal by measuring a second amplitude of a second signal component of the output signal corresponding to the second frequency; calculating an estimated impedance for each of the plurality of electrodes based on the retrieved output amplitudes of the plurality of test signals; generating a quantitative indication of the condition of the plurality of electrodes based on the calculated estimated impedances for the plurality of electrodes; and providing the quantitative indication of the condition of the plurality of electrodes to a user. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for monitoring a condition of a plurality of electrodes used in the measurement of a biological signal, the system comprising:
a circuit configured to; apply a plurality of test signals to the plurality of electrodes, wherein the circuit is configured to apply a first test signal having a first frequency to at least one of the plurality of electrodes and concurrently apply a second test signal having a second frequency different from the first frequency to at least one of the plurality of electrodes at a same time during which the first test signal is applied, wherein both the first frequency and the second frequency are below a frequency range associated with the biological signal, capture the biological signal while applying the plurality of test signals and generate an output signal that includes both the measured biological signal and the plurality of test signals, retrieve an output amplitude for each of the plurality of test signals from the output signal, retrieving the output amplitude for each of the plurality of test signals including; determining the output amplitude for the first test signal by measuring a first amplitude of a first signal component of the output signal corresponding to the first frequency, and determining the output amplitude for the second test signal by measuring a second amplitude of a second signal component of the output signal corresponding to the second frequency, calculate, for each electrode, a plurality of estimated impedance values over a measurement timeframe based on the retrieved output amplitudes of the plurality of test signals, and calculate, for each electrode, an estimated impedance based on a combination of the plurality of estimated impedance values for the electrode. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A system for measuring an electrocardiogram (ECG) signal, the system comprising:
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a plurality of electrodes; a circuit comprising a microprocessor and a DC amplifier, wherein the circuit is configured to; apply a plurality of test signals to the plurality of electrodes, wherein the circuit is configured to apply a first test signal having a first frequency to at least one of the plurality of electrodes and concurrently apply a second test signal having a second frequency to at least one of the plurality of electrodes at a same time during which the first test signal is applied, wherein both the first frequency and the second frequency are less than 0.5 Hz and are below a frequency range associated with the ECG signal, capture the ECG signal while applying the plurality of test signals and generate, using the DC amplifier, an output signal that includes both the measured ECG signal and the plurality of test signals, retrieve an output amplitude for each of the plurality of test signals from the output signal, retrieving the output amplitude for each of the plurality of test signals including; determining the output amplitude for the first test signal by measuring a first amplitude of a first signal component of the output signal corresponding to the first frequency, and determining the output amplitude for the second test signal by measuring a second amplitude of a second signal component of the output signal corresponding to the second frequency, calculate an estimated impedance for each of the plurality of electrodes based on the retrieved output amplitudes of the plurality of test signals, generate a quantitative indication of the condition of the plurality of electrodes based on the calculated estimated impedances for the plurality of electrodes, the quantitative indication for each electrode comprising a value indicative of a relative quality of an electrode connection based on comparison of the calculated estimated impedance to at least one of; an initial impedance value measured at application of the electrode, or a reference impedance value associated with a predetermined quality of the electrode connection, compare the estimated impedance for the electrode with a threshold impedance, generate an alert separate from the quantitative indication to the user indicating a problem with the electrode when the estimated impedance for the electrode exceeds the threshold impedance, and provide the quantitative indication of the condition of the plurality of electrodes and the alert to the user. - View Dependent Claims (22, 23)
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Specification