Comparison of classical and two-stage methods of Barkhausen noise measurement

The purpose of the article was to investigate properties of the two-stage methods of the Barkhausen noise (BN) measurement used in non-destructive testing. The principle of the two-stage method is based on subtraction of two successive instances of the electromotive force (EMF) signal with the same non-stochastic (continuous) component. The subtraction can be accomplished in a hardware (hardware two-stage method) or in a software (software two-stage method). The experiments proved that, with these methods, we are able to significantly suppress the dominant continuous component from the induced EMF signal without using filters and thus simplify the measurement. On the other hand, with the classical one-stage method, to achieve similar suppression of the continuous component and, simultaneously, to not suppress the BN, it was necessary to adjust the cut-off frequency of the high-pass filter.