## 3 Results
Figure 12 presents the acquisition and processing of EEG biopotentials for \(\beta\) and \(\alpha\) signals. Figure 12a shows the EEG signals resulting from filtering for the \(\beta\) signal in the time domain, and Figure 12b presents these signals in the frequency domain. In both representations, the proposed configuration (blue) shows a better reduction of 60 Hz power line noise compared to the configuration reported in the literature (red). Figure 12c displays the EEG signals after filtering for the \(\alpha\) signal in the time domain, while Figure 12d shows the frequency spectra of the signals from Figure 12c. In both representations, the proposed configuration (blue) provides a better 60 Hz noise reduction than the configuration reported in the literature (red). For sEMG and ECG biopotential acquisition and processing, the resulting signals are presented in Figure 13. Figure 13a shows the sEMG signals in the time domain, and Figure 13b presents the frequency spectrum of the sEMG signals from Figure 13a. An improved reduction of a 60 Hz power line noise can be observed using the proposed configuration (blue) compared to the signal acquired with the configuration reported in the literature (red). Figure 13c,d show the experimental results for ECG signals acquired with the proposed configuration (blue) and the configuration from the literature (red). Similar to the results for EEG and sEMG signal acquisition, the ECG signal acquired with the proposed configuration demonstrates better noise reduction. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline  & **This System** & [41] & [44] & [45] & [46] & [47] & [48] & [49] & [50] & [51] & [52] & [54] & [55] \\ \hline CMRR (dB) & 141.767 & 66 & 83 & 98 & 80–93 & 76 & 110 & 74 & 120 & 100 & 110 & 120 & 60 \\ \hline \end{tabular}
\end{table} 
Table 2: CMRR-based performance comparisons. Figure 11: Experimental results of the CMRR of the proposed system as a function of different input voltages. Figure 12: EEG \(\beta\) signal acquisition: (**a**) time-domain representation of the EEG signal acquired with the proposed configuration (blue signal) and with the configuration reported in the literature (red signal); (**b**) frequency spectrum of the time-domain signals shown in (**a**). EEG \(\alpha\) signal acquisition: (**c**) time-domain representation of the EEG signal acquired with the proposed configuration (blue signal) and with the configuration reported in the literature (red signal); (**d**) frequency spectrum of the time-domain signals shown in (**c**). Figure 13: sEMG signal acquisition: (**a**) time-domain representation of the sEMG signal acquired with the proposed configuration (blue signal) and with the configuration reported in the literature (red signal); (**b**) frequency spectrum of the time-domain signals shown in (**a**). ECG signal acquisition: (**c**) time-domain representation of the ECG signal acquired with the proposed configuration (blue signal) and with the configuration reported in the literature (red signal); (**d**) frequency spectrum of the time-domain signals shown in (**c**). A phase shift was introduced between the two signals to better observe the noise difference in both time and frequency domains. In Figures 12b,d and 13b,d, the blue line at 60 Hz in the frequency domain shows an amplitude difference compared to the red dotted signals. Additionally, in the frequency-domain figures, the blue signal displays only a small peak at 60 Hz. However, since a significant phase shift was not added, the red 60 Hz peak, indicating the signal acquired with the configuration reported in the literature, may appear as if it belongs to the signal obtained with the proposed system. Finally, the SNR is calculated for the EEG, sEMG, and ECG signals in Figures 12 and 13. The EEG \(\beta\) and \(\alpha\) biopotentials have SNR values of 39.4534 dB and 31.5643 dB, respectively. For the sEMG and ECG signals, the SNR values are 30.5287 dB and 29.8654 dB, respectively.