Transient and harmonic eddy currents: Lift-off point of intersection

It has been previously determined experimentally that the transient responses of pulsed eddy current excitation of a conductive semi-infinite plane pass through a common point, regardless of the lift-off value. The origin of this intersection point is investigated and related to the harmonic components of the Fourier series representation of the pulse. Discrete sinusoidal signals, when individually sent through the same inspection system, also exhibit this common point feature when only the lift-off is varied. Moreover, the transient responses can be reconstructed from the harmonic outputs by using truncated Fourier series.