Patent ID: 9086385
Filing Date: 2015-07-21
Classification: G01N

Abstract:
1. A method for nondestructive and noncontact detection of faults in a test piece which is moving relative to the device, comprising: exposing the test piece to a plurality of periodic alternating electromagnetic fields with a transmitter coil arrangement; detecting a periodic electrical signal with a receiver coil arrangement, such that the periodic electrical signal has a carrier oscillation where at least one of an amplitude and a phase is modulated by a fault in the test piece when the fault is detected by the receiver coil arrangement; digitizing the receiver coil signal with an A/D converter stage; producing a useful signal from the digitized receiver coil signal with a signal processing unit; evaluating the useful signal with an evaluation unit for detecting a fault in the test piece; monitoring a curve shape of the digitized received coil signal when overdriving the A/D converter stage by the receiver coil signal is ascertained by the signal processing unit, truncating a part of the receiver coil signal with the A/D converter stage; and reconstructing the receiver coil signal with a mathematical approximation in the digitized receiver coil signal.