Implementation of digital methods to analyze eddy-current signals based on the E14-440 module

Abstract

Nondestructive testing methods utilize various sensors, and different signal types require different processing methods. Digital implementation of signal processing methods can expand the variety of methods implemented by one system. An eddy-current test system based on the E14-440 module has been developed. Quadrature amplitude demodulation and fast Fourier transformation are implemented to analyze the signal. The amplitude, phase, and complex parts of the signal are calculated. It is shown that both methods are applicable and allow elimination of some analog circuits. However, digital signal processing significantly depends on conversion rates and synchronization between generation and pickup of the signal.