Patent ID: 8629677

Claim:
A method comprising metal detecting by using a truncated half sine of magnetizing current, energizing a transmit coil past the current peak, then truncating and abruptly switching off the current, taking a first ground balanced receive sample in a vicinity of the sine current peak, followed by a ceasing of the inducing current and causing an abrupt end of the magnetizing current and field, followed after the transmit current ceases by taking a second receive sample of eddy current from a detectable target object, and detecting a remanent component signal of a ground composite signal during the induction balance half sine peak, wherein a permeability component is zero and adding or subtracting the remanent component from pulse data at a specific sampling point or points to characterize the eddy current from the target object in both induction balance modes and pulse decaying modes by comparing the data from both of the modes.