Electronically tunable versatile voltage-mode MIMO OTA-C universal filter

Abstract

This paper presents a new versatile high input impedance voltage-mode universal filter with multiple-input multiple-output (MIMO) based on single-ended operational transconductance amplifiers (OTAs) and grounded capacitors. The proposed circuit can work as a two-input four-output filter and a three-input single-output filter without changing the circuit topology. The natural frequency (ω o ) and the quality factor (Q) can be set orthogonally by adjusting the circuit components. The ω o can also be controlled electronically by varying the transconductance value of OTAs. The simulation results are performed to confirm the presented theory.

0.5 V Differential Difference Transconductance Amplifier and Its Application in Voltage-Mode Universal Filter

“…First, the input BD transistors M1-M2 have been replaced by BD MI-MOS transistors that allowed simplification of the overall structure, namely removing one differential stage, since summation of signals is realized by the passive capacitances CBi. The second modification is the addition of the second PPF circuit M7-M8, applied directly to the input non-tailed differential pair, in the same configuration as previously described in [37,38]. To the best of the authors' knowledge, the application of two PPF circuits instead of one is the original solution proposed in this DDA structure.…”

Voltage-Mode Multifunctional Biquadratic Filter Using VDDDA

“…In the past decades, the previous studies on multifunction active biquad filter by using OTA consisted of four categories: (i) a single input, single output (SISO) [2,3], (ii) a single input, multiple output (SIMO) [4][5][6][7], (iii) multiple-input, single-output (MISO) [8], and (iv) multiple-input, multiple-output (MIMO) [9,10]. The circuits in [4]- [10] enjoyed high input impedance and used grounded capacitor, but these structures of circuits contained many active devices.…”