Miyagoshi „Interpretation of Printed Circuit Boards Structure via Amplitude and Signal Phase Obtained from ECT Testing”, 6th Int. Workshop on Electromagnetic Non-destructive Evaluation, 2000.6. This document was created with Win2PDF available at http://ww

Abstract. This paper presents a innovative method of image processing utilizing both the phase and amplitude characteristics of the output signal of an ECT probe. A unique probe has been designed and fabricated for the inspection of printed circuit boards ’ (PCB) structure.. The probe is composed of a meander-exciting coil and of a solenoid pick-up coil. The probe can detect various defects in PCB’s conductors such as cracks, partial declines, and chipped defects. The signal’s amplitude and phase, obtained as resultant data from the inspection, deliver information about defects, the geometry of conductors and the positions of soldering points. The strong relationship between the amplitude and the phase allows a new approach to signal analysis, where the amplitude and the phase are combined in a filtering process. Data from the phase characteristic sare used to set thresholds in the amplitude’s filtering process. This process improves the interpretation of signals obtained and the quality of the final image