Method and apparatus for determining impedance variation at skin / electrode interface
Patent
Overview
Overview
abstract
In a medical device that measures electrical signals generated by a patient's body, a system for monitoring the skin / electrode impedance of a patient and compensating for the effects of continuously changing skin impedance is provided. An electrode having a selectively variable impedance applied to a skin of a patient, an instrumentation amplifier coupled to the electrode, an auxiliary filter / gain module, and a servo integrator. A monitoring module; and a test generation module coupled to the monitoring module and the electrode and configured to apply a test signal to the electrode. And a measurement module having a voltage calibrator configured to measure an AC level between the electrodes while the test signal is applied to the electrodes, wherein a total impedance of the electrodes and skin is measured. The gain of the monitoring module is adjusted proportionally.
