Metal discrimination using time domain processed sinc signal

This paper describes the application and time domain signal processing of polyharmonic sinc function as an excitation signal for eddy current metal detectors. Limitations of all conventional eddy current metal detectors or induction devices in general reside in its limited ability to discriminate or unequivocally identify detected materials. To better identify or classify materials, the excitation signal and its following processing in the detector should be done. The paper is focused on the processing of the polyharmonic sinc signal in the time domain in order to improve the discrimination ability into ferromagnetic and non-ferromagnetic materials. Processing of polyharmonic signal in time domain bring a fast and undemanding method. Spheres of different diameters and from different ferromagnetic and non-ferromagnetic materials were used as specimens. Experimental measurements were processed in time domain only - standard integral parameters of the signal were used for target identification.