A METHOD AND APPARATUS FOR PHASE SENSITIVE DETECTION OF EDDY CURRENT MEASUREMENTS

摘要

exciting eddy currents in a test material using an eddy current probe driven by a drive signal; detecting induced eddy currents in the test material; converting the detected signal into integer values using an analog to digital converter; and adding or subtracting the generated integer values to or from each of two accumulators, or taking no action, so that one accumulator produces a value proportional to one component of the detected signal and the other produces a value proportional to another component of the detected signal and using these values to detect the presence of a defect.