## 8 Conclusions  
In this research, a truly mixed-mode universal filter based on VDBA is proposed. The filter requires three VDBAs, two capacitors, and a resistor for implementation. It provides all five filter responses in all four modes of operation in MISO configuration. A SIMO resistorless CM universal filter can also be derived from the same core arrangement. In MISO configuration, the VM/TIM outputs are available from low impedance nodes and CM/TAM outputs are available from high impedance node leading to cascadability. The filter has a feature of inbuilt tunability as well. The detailed theoretical analysis, non-ideal, and sensitivity analyses are performed to establish the correct functioning of the filter. The VDBA-based filter is designed and validated in Cadence Virtuoso software using Silterra Malaysia 0.18 \(\upmu\)m PDK. The filter is designed for a characteristic frequency of 16.66 MHz with a \(\pm\)1.25 V supply. The Monte Carlo analysis shows that the frequency deviation is within acceptable limits. Additionally, the THD is within 5% for a substantial voltage/current input signal range. The experimental validation of the proposed filter is also carried out. The filter is constructed using commercially available ICs. The frequency responses and time-domain results of the filter confirm the correct functioning. The simulation and experimental results are found consistent with the theoretical predictions.  
Conceptualization, M.F., N.H. and S.S.; methodology, M.F.; software, M.F. and S.S.; validation, M.F., S.S. and W.T.; formal analysis, M.F. and N.H.; investigation, M.F.; resources, S.H.M.A.; data curation, M.F. and N.H.; writing--original draft preparation, M.F., N.H. and W.T.; writing--review and editing, M.F., N.H. and W.T.; visualization, M.F. and N.H.; supervision, N.H., S.H.M.A.; project administration, S.H.M.A.; funding acquisition, S.H.M.A. All authors have read and agreed to the published version of the manuscript.  
This research work was funded by University Kebangsaan Malaysia (UKM) under grant (GUP2020-009).  
Not applicable.  
The data presented in this study are available on request from the authors.  
The authors declare no conflicts of interest.  
The following abbreviations and symbols are used in this manuscript:  
\begin{tabular}{l l} \(\beta\) & Frequency dependent non-ideal voltage gain \\ \(\gamma_{\gamma},\gamma^{\prime}\) & Frequency dependent non-ideal transconductance transfer gains \\ \(\mu\) & Carrier mobility \\ ABB & Active building blocks \\ AP & All-pass \\ BP & Band-pass \\ BR & Band-reject \\ CCII & Second-generation current conveyor \\ CDBA & Current differencing buffer amplifier \\ CFOA & Current feedback operational amplifier \\ CM & Current-mode \\ C\({}_{\text{ox}}\) & Gate oxide capacitance per unit area \\ DDCC & Differential difference current conveyor \\ DDCCII & Differential difference current conveyor \\ DVCC & Differential voltage current conveyor \\ EXCCTA & Extra X current conveyor transconductance amplifier \\ FB-VDBA & Fully balanced voltage differencing buffered amplifier \\ FB-VDIBA & Fully balanced voltage differencing inverting buffered amplifier \\ FDCCII & Fully Differential Current Conveyor \\ \end{tabular}