## 3 Simulation Results
Figure 13a,b show, respectively, the BPF's magnitude frequency responses of the VM and CM when the power supply was changed to 0.9 V, 1 V, and 1.1 V. Figure 14a,b show, respectively, the BPF's magnitude frequency responses of the VM and CM when the temperatures were changed to \(-25\)\({}^{\circ}\)C, \(0\)\({}^{\circ}\)C, \(27\)\({}^{\circ}\)C, and \(75\)\({}^{\circ}\)C. From this result, at a temperature of \(27\)\({}^{\circ}\)C, the center frequency was 10 kHz, and was changed by 18.8%, 9.6%, and 14.9% when the temperature was changed to \(-25\)\({}^{\circ}\)C, \(0\)\({}^{\circ}\)C, and \(75\)\({}^{\circ}\)C, respectively. Figure 11: The simulated frequency response of BPF for: (**a**) the natural frequency was varied by \(\mathrm{I_{set}}\) (\(\mathrm{I_{set}}=\mathrm{I_{set1}}=\mathrm{I_{set2}}\)), (**b**) the quality factor was varied by \(\mathrm{I_{set3}}\). Figure 12: The simulated frequency response of the BPF when the process was varied: (**a**) VM, (**b**) CM. The Monte Carlo analysis with 200 runs and 15% tolerance of the capacitors \(C_{1}\) and \(C_{2}\) was performed and the BPF of both VM and CM were selected to be shown. Figure 15 shows the histogram of the Monte-Carlo analysis of the center frequencies for the BPF of (a) VM and (b) CM. Figure 15a, shows that the standard deviation (sigma) was 825.593 Hz, the mean was 10.045 kHz, and the minimal and maximal center frequencies were 8.031 kHz and 12.382 kHz, respectively, whereas the standard deviation was 825.435 Hz, the mean was 10.047 kHz, and the minimal and maximal center frequencies were 8.032 kHz and 12.386 kHz, respectively, for Figure 15b. To investigate the linearity of the proposed mixed-mode universal filter, the LPF's 10 kHz of the natural frequency was selected for testing, and the in-band frequency of 1 kHz was applied to the inputs, and both the VM and the CM were tested. Figure 16a,b show, respectively, the THDs of VM and CM with different input amplitudes, Figure 16c shows the input and output waveforms of VM of 0.983% THD (V\({}_{\text{in}}\) = 170 mV), and Figure 16c shows the input and output waveforms of CM of 1.05% THD (I\({}_{\text{in}}\) = 5 \(\mu\)A). Figure 14: The simulated frequency response of the BPF when the temperature was varied: (**a**) VM, (**b**) CM. Figure 13: The simulated frequency response of the BPF when the supply voltage was varied: (**a**) VM, (**b**) CM. Figure 17a,b show, respectively, the equivalent output noise of the VM and CM of the LPF. The integrated output noises in the bandwidth of 10 kHz were 156.5 \(\upmu\)V for the VM  
Figure 16: Simulated THD results of LPF: (**a**) THD with different voltage input amplitude of VM, (**b**) THD with different current input amplitude of CM, (**c**) input and output waveforms of 0.983% THD of VM, (**d**) input and output waveforms of 1.05% THD of CM. Figure 15: Simulated Monte-Carlo analysis for the BPF with 15% tolerance of the capacitors \(C_{1}\) and \(C_{2}\): (**a**) histogram for VM, (**b**) histogram for CM. and 0.729 nA for the CM. The dynamic ranges can be calculated as 57.7 dB for the VM and 73.7 for the CM. A comparison of the performance of the proposed filter with some previous works is shown in Table 4. For a fair comparison, the mixed-mode universal filters in [14; 31; 32; 42; 43; 46] were selected. In [14], the filter using FDCCII and DDCC can provide many filter responses into the same circuit, the filters using OTAs in [31; 32] can operate with low-voltage and low-power, and the recent filters in [42; 43; 46] use new active building blocks. Compared to [31; 32], the proposed filter uses lesser active building blocks. Compared with the proposed structure, the filters in [42; 44; 47] enjoy using a minimum number of active elements, but to realize some transfer functions, these filters apply the voltage signals via the capacitors or resistors, which is not preferable for voltage-mode circuits, while the filters in [42; 47] obtain the output currents via the capacitors or resistors which is not preferable for current-mode circuits.