## 2 Experimental Setup  
Measurements were made for conventional grain-oriented electrical steel sheets. The steel was cold rolled. As a result of rolling, such steel has anisotropic magnetic properties. Consequently, it is characterized by the occurrence of easy and hard magnetization axes. In the first case, the magnetic saturation state is achieved for a relatively lower value of the magnetizing field. In contrast, the direction of hard magnetization requires the use of higher field values for the same purpose. Barkhausen Noise is one of the methods that can be used to characterize anisotropic properties, as the noise activity and the dynamics of the MBN phenomenon are strictly dependent on the direction of the magnetizing field with respect to the rolling axis [20; 21; 25; 26; 27]. Before the measurements, no additional treatment was made to the material. The steel parameters are presented in Table 1.  
The measurements were made for the transducer's 101 angular arrangement \(\alpha\) within the (0\({}^{\circ}\)-180\({}^{\circ}\)) range, following a constant step of 1.8\({}^{\circ}\). Figure 1 shows a schematic diagram of the sample with the visualization of the position of the transducer at the 0\({}^{\circ}\)angle and marks of the direction of further rotation (depicted with a blue arrow). The first measurement was conducted for the transducer aligned along the 0\({}^{\circ}\) angle (the transverse direction TD), which means that magnetization was perpendicular to the rolling direction (angle \(\alpha\) = 90\({}^{\circ}\) is the angle parallel to the rolling direction RD). The measurements were fully automated. The positioning of the transducer and signal acquisition was managed by a computer. Signals were acquired and generated by the DAQ measurement card (NI-PCI-6251). The measurements were performed using a sinusoidal excitation wave with a frequency of 10 Hz. The excitation current was 370 mA, which corresponds to the value of approximately 1.6 kA/m of magnetizing field. A detailed description of the transducer and measuring system can be found in [19; 20; 21; 28]. Before the data acquisition process, the signal was filtered using analog filters with the pass band set to the 2 kHz-100 kHz range. Detailed information on the filtration settings was provided by the authors in [21]. For each angle, 10 measurements were made, and for a single \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**Steel Parameters**} \\ \hline Length/Width & 150 mm \\ Thickness & 0.23 mm \\ Lossiness & 1.10 W/kg \\ Induction & 1.80 T \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Steel parameters. Figure 1: Diagram which illustrates: the sample, transducer, and depicts the direction of rotation, direction of the rolling axis (RD) and transvers direction (TD—it is perpendicular to the rolling axis). measurement, the 10 periods of the magnetization process were acquired. The voltage signal sensed by the measuring coil (\(U_{\text{BN}}\)) was sampled at the frequency of 250 kHz and then processed using the developed digital signal processing procedure. The exemplary results of \(U_{\text{BN}}\) burst along with the magnetizing current \(I_{e}\) obtained for the 0, 45 and 90 degree positions of the transducer with respect to the TD are presented in Figure 2. One can clearly notice the difference in the course and dynamics of the observed Barkhausen effect depending on the alignment of the transducer. The greatest activity, especially in the context of the dynamics and the value level of the main MBN peak, can be observed in the 90\({}^{\circ}\) direction (RD). This refers to the easier conduction of the magnetization course. As the dynamics of the process changes, the analysis of the combined domains of time and frequency can be useful. This was also shown earlier by authors in [20; 21], where the possibility of the utilization of selected time-frequency transformation to MBN signal for the evaluation of anisotropy was deeply discussed.