## 7 Experimental Validation  
To further verify the correct functioning of the proposed filter circuit and to complement the theoretical and simulation results, detailed experimental analysis is carried out for MISO VM and TAM modes and SIMO CM configuration. The VDBA is built with available integrated circuits (ICs), the Intersil CA3080 OTAs and Texas Instruments LF356 op-amp, as shown in Figure 19. The supply voltages are set \(\pm\)5 V.  
To design the filter for a pole frequency of \(f_{0}=\omega_{0}/2\pi=100.27\) kHz and \(Q=1\), the active component values are selected as \(g_{\mathrm{m}}=g_{\mathrm{m}i}\) (\(g_{\mathrm{m}}\) of \(i\)-th VDBA, \(i=1\), \(2\), \(3\)) = 0.63 mA/V (\(I_{B}=31.5\)\(\mu\)A), where \(g_{\mathrm{m}}=\frac{I_{\mathrm{B}}}{2V_{\mathrm{T}}}\) and \(V_{\mathrm{T}}\) is thermal voltage \(\cong\) 25 mV at 27 \({}^{\circ}\)C. In all measurements, the passive components are chosen as \(R_{1}=1\) k\(\Omega\), and \(C_{1}=C_{2}=1\) nF. The measured LP, HP, BP, BR, and AP frequency response results of the VM MISO configuration in Figure 2 are given in Figure 20. Figure 21 also presents the measured time-domain responses for LP, HP, BP, and BR filters, when the sinusoidal input signal of an amplitude 100 mV peak-to-peak at 100 kHz is applied. In addition, the measurement of input and output voltage waveforms of the VM AP filter and the FFT analysis results at the \(V_{\mathrm{OUT}}\) output terminal are given in Figure 22, respectively.  
For obtaining the TAM and CM SIMO filter results, two additional Analog Devices AD844s and a converting resistor (\(R_{\mathrm{C}}\)) are employed to covert current to voltage. The circuit is shown in Figure 23, where the value of \(R_{\mathrm{C}}\) is equal to 1 k\(\Omega\). Figure 24 shows the measured TAM filtering responses with the same component values as described above for \(f_{0}=100.27\) kHz and \(Q=1\). Next, Figure 25 shows the time-domain responses of the proposed TAM operation for LP, BP, HP, and BR filters. In Figure 26, the measured input and output voltage waveforms of the TAM AP filter and its FFT spectrum analysis are, respectively, given.  
In the same way, the LP, HP, and BP filter responses of the CM SIMO filter in Figure 3 are presented in Figure 27. In this case, the circuit components are the same as that used in the above design to have the following filter characteristics: \(f_{0}=100.27\) kHz and \(Q=1\). As expected, the experimental results of the CM SIMO configuration are close to the theoretical results.  
From the experimental results, it is evident that the proposed filter topologies are practically realizable. The deviation in the measurement results is mainly due to the breadboard circuit implementation. It is expected that, when the filter circuit is fabricated, the behavior of the proposed filter will be very close to the simulation results.  
Figure 19: VDBA implementation using off-the-shelf ICs.  
Figure 21: VM MISO configuration: Measured input and output waveforms of the (**a**) LP, (**b**) HP, (**c**) BP, and (**d**) BR.  
Figure 20: VM MISO configuration: Measured gain and phase responses of the (**a**) LP, (**b**) HP, (**c**) BP, (**d**) BR, and (**e**) AP.  
Figure 23: Voltage to current conversion setup for obtaining TAM and CM SIMO filter results.  
Figure 24: TAM MISO configuration: Measured gain and phase responses of the (**a**) LP, (**b**) HP, (**c**) BP, (**d**) BR, and (**e**) AP.  
Figure 22: VM MISO configuration: (**a**) measured input and output waveforms of the AP filter, (**b**) its FFT analysis results.  
Figure 27: CM SIMO configuration: Gain responses of the LP, BP, and HP filter.  
Figure 25: TAM MISO configuration: Measured input and output waveforms of the (**a**) LP, (**b**) HP, (**c**) BP, and (**d**) BR.  
Figure 26: TAM MISO configuration: (**a**) measured input and output waveforms of the AP filter, (**b**) its FFT analysis results.