## 3 Experimental Verification
The signals that need to be collected in the experiment include analog signals of the voltage at both ends of the sampling resistor connected in series with the primary winding (primary winding), used to generate the magnetic field strength \(H\) signal, and analog signals of the voltage at both ends of the secondary winding, used to calculate the magnetic induction strength \(B\) signal. Both \(B\) and \(H\) signals adopt the differential measurement mode, meaning that each signal requires two input channels for collection. The DAQ assistant module of NI LabVIEW can help users quickly initialize and set output and acquisition channels. Therefore, when using this platform, it is necessary to correctly set the input and output channels in the LabVIEW platform to complete the signal output and acquisition process correctly. In addition, the functions of signal amplification and isolation are completed by a power amplifier and isolation amplifier, respectively, to reduce error and ensure safety. The role of the isolation amplifier can be simply understood as \"isolation\" and \"amplification\". The \"isolation\" refers to electrical isolation of the sample to be measured from the host computer, to prevent abnormal signals or step signals of the sample from harming the host computer and the data acquisition card; \"amplification\" refers to the external signals collected to amplify a certain number of times in order to improve the accuracy of the experiment and reduce the experimental error. The power amplifier plays the role of power amplification of the excitation signal, and the waveform output from the output channel of the data acquisition card cannot be used directly for the excitation function but needs to be amplified by the power amplifier to form a stable excitation signal. The equipment models are shown in Table 4. The experimental equipment diagram is shown in Figure 9. \begin{table}
\begin{tabular}{c c} \hline \hline
**Equipment Name** & **Model Number** \\ \hline Isolation Amplifier & Nanjing Hongbin Weak Signal Inspection Co., Nanjing, China. HB-814A \\ Power Amplifier & Aigtek, Xi’an, China. ATA-308 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Physical parameters of grain-oriented silicon steel samples. \begin{table}
\begin{tabular}{c c} \hline \hline
**Technical Parameters** & **Model/Value** \\ \hline Silicon steel grade & B27R085 \\ Manufacturer & BAOSHAN IRON \& STEEL Co., Ltd. \\ Expected \(\text{B}_{\text{s}}/\text{T}\) & 1.5 \\ Conductivity of silicon steel/\(\text{S}\cdot\text{m}^{-1}\) & 2.22 \(\times\) 10\({}^{6}\) \\ Density of silicon steel/\(\text{kg}\cdot\text{dm}^{-3}\) & 7.65 \\ N\({}_{1}/\text{N}_{2}\) & 10 \\ Area \(S/\text{cm}^{2}\) & A \(\times\) D \\ Stacking factor/\% & 97.5 \\ Type of Coating & Inorganic \\ Hardness (HV1) & 200 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Parameters of grain-oriented silicon steel samples. It should be noted here that both the power amplifier and the isolation amplifier used in the experiment do not affect the results of the experiment, and their amplification of the input signal is linear. The role of the power amplifier is observed through an experiment: the power amplifier is set to \(\times 10\) the voltage amplification ratio, the input signal is an industrial frequency, the sinusoidal signal of amplitude is 1 V, and the signal at its output is monitored, as shown in Figure 10a. When the frequency of the input signal is 1.55 kHZ (the highest number of harmonics monitored in Figure 4 is 31), the output image is as shown in Figure 10b. It can be seen that the output signal is linearly amplified. This proves that the use of the amplifier does not affect the experimental results. ### Experimental Principles and Platform Construction  
The functions of a complete magnetic characteristic measurement system include the demagnetization function, excitation signal generation function, and data processing function, which are all realized by the graphical programming language of the LabVIEW platform.