## 2 Proposed Circuit
### Proposed Mixed-Mode Universal Filter
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{2}{c}{**Filtering Function**} & **Input** & **Output** & **Condition** \\ \hline \multirow{8}{*}{BSF} & Non-inverting & \(V_{3}\) & \(V_{o2}\) & - \\ \cline{2-5}  & Inverting & \(V_{4}\) & \(V_{o2}\) & - \\ \cline{2-5}  & Non-inverting & \(V_{2}=V_{7}\) & \(V_{o2}\) & - \\ \cline{2-5}  & Non-inverting & \(V_{2}=V_{7}\) & \(V_{o5}\) & - \\ \cline{2-5}  & Non-inverting & \(V_{4}\) & \(V_{o7}\) & - \\ \cline{2-5}  & Inverting & \(V_{3}\) & \(V_{o7}\) & - \\ \cline{2-5}  & Non-inverting & \(V_{2}=V_{7}\) & \(V_{o2}\) & - \\ \hline \multirow{8}{*}{APF} & Non-inverting & \(V_{3}=V_{5}\) & \(V_{o2}\) & \(g_{m2}=g_{m3}\) \\ \cline{2-5}  & Inverting & \(V_{4}=V_{6}\) & \(V_{o2}\) & \(g_{m2}=g_{m3}\) \\ \cline{2-5}  & Non-inverting & \(V_{2}=V_{3}=V_{7}\) & \(V_{o5}\) & - \\ \cline{2-5}  & Non-inverting & \(V_{2}=V_{5}=V_{7}\) & \(V_{o5}\) & - \\ \cline{2-5}  & Non-inverting & \(V_{4}=V_{6}\) & \(V_{o7}\) & - \\ \cline{2-5}  & Inverting & \(V_{3}=V_{5}\) & \(V_{o7}\) & - \\ \cline{2-5}  & Inverting & \(V_{2}=V_{5}=V_{7}\) & \(V_{o7}\) & - \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._ \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Filtering Function**} & **Input** & **Output** & **Condition** \\ \hline \multirow{8}{*}{LPF} & Non-inverting & \(I_{2}=I_{5}\) & \(I_{o1}\) & \(g_{m2}=g_{m3}\), \(C_{1}=C_{2}\) \\ \cline{2-5}  & Inverting & \(I_{2}=I_{5}\) & \(I_{o2}\) & \(g_{m2}=g_{m3}\), \(C_{1}=C_{2}\) \\ \cline{2-5}  & Non-inverting & \(I_{4}\) & \(I_{o3}\) & - \\ \cline{2-5}  & Inverting & \(I_{5}\) & \(I_{o3}\) & - \\ \cline{2-5}  & Non-inverting & \(I_{5}\) & \(I_{o4}\) & - \\ \cline{2-5}  & Inverting & \(I_{4}\) & \(I_{o4}\) & - \\ \cline{2-5}  & Non-inverting & \(I_{4}\) & \(I_{o5}\) & - \\ \cline{2-5}  & Inverting & \(I_{4}\) & \(I_{o6}\) & - \\ \cline{2-5}  & Non-inverting & \(I_{2}\) & \(I_{o1}+I_{o3}\) & - \\ \hline \multirow{8}{*}{HPF} & Non-inverting & \(I_{3}\) & \(I_{o1}\) & - \\ \cline{2-5}  & Inverting & \(I_{3}\) & \(I_{o2}\) & - \\ \cline{2-5}  & Non-inverting & \(I_{1}\) & \(I_{o3}\) & Gain \((g_{m3}R_{1})\) \\ \cline{2-5}  & Inverting & \(I_{1}\) & \(I_{o4}\) & Gain \((g_{m3}R_{1})\) \\ \cline{2-5}  & Non-inverting & \(I_{1}\) & \(I_{o5}\) & Gain \((g_{m3}R_{1})\) \\ \cline{2-5}  & Inverting & \(I_{1}\) & \(I_{o6}\) & Gain \((g_{m3}R_{1})\) \\ \cline{2-5}  & Inverting & \(I_{5}\) & \(I_{o1}+I_{o6}\) & \(g_{m2}=g_{m3}\), \(C_{1}=C_{2}\) \\ \cline{2-5}  & Inverting & \(I_{5}\) & \(I_{o2}+I_{o5}\) & \(g_{m2}=g_{m3}\), \(C_{1}=C_{2}\) \\ \hline \multirow{8}{*}{BPF} & Non-inverting & \(I_{4}\) & \(I_{o1}\) & - \\ \cline{2-5}  & Inverting & \(I_{5}\) & \(I_{o1}\) & - \\ \cline{1-1} \cline{2-5}  & Non-inverting & \(I_{5}\) & \(I_{o2}\) & - \\ \cline{1-1} \cline{2-5}  & Inverting & \(I_{4}\) & \(I_{o2}\) & - \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Obtaining variant filtering functions of the CM filter. The natural frequency (\(\omega_{o}\)), bandwidth (\(BW\)), and quality factor (\(Q\)) of the filters can be expressed, respectively, by  
\[\omega_{o}=\sqrt{\frac{g_{m1}g_{m2}}{C_{1}C_{2}}} \tag{34}\]  
\[BW=\frac{g_{m3}}{C_{2}} \tag{35}\]  
\[Q=\frac{1}{g_{m3}}\sqrt{\frac{g_{m1}g_{m2}C_{2}}{C_{1}}} \tag{36}\]  
The parameter \(\omega_{o}\) can be controlled electronically by \(g_{m1}\) and \(g_{m2}\), parameters \(BW\) and \(Q\) can be controlled electronically by \(g_{m3}\). Thus, parameters \(\omega_{o}\) and \(Q\) can be orthogonally controlled.