Patent ID: 6487449
Filing Date: 2002-11-26
Classification: A61B

Abstract:
A system for detecting faults in electrodes used to measure physiological activity of a subject, the system comprising:at least one carrier signal electrode to deliver a carrier signal to the subject; at least one activity electrode to sense a combined signal having an activity portion and a carrier signal portion; and a signal processor coupled to the at least one activity electrode, the signal processor including a first splitter to divide the combined signal into a first signal with an activity portion and a carrier signal portion and a second signal with an activity portion and a carrier signal portion, a filter coupled to the first splitter to receive the first signal and substantially remove the first signal's carrier signal portion and having an output signal, a second splitter coupled to the filter to divide the output signal into a first output signal and a second output signal, a combiner coupled to the first and second splitters to subtract the second signal from the second output signal to produce a second carrier signal, and an impedance calculator coupled to the combiner to calculate an impedance value based on the second carrier signal.