Resistorless Transconductance-mode Multifunction Filter with Orthogonal and Electronic Tune of Natural Frequency and Quality Factor

This work provides the synthesis of multifunction biquad active filter which has three input voltage nodes and single output current node. The synthesis procedure which is based on the RLC parallel circuit is given step by step. An analog active building block employed in this synthesis is the modified current controlled current conveyor transconductance amplifier (M-CCCCTA). The proposed filtering structure consists of two M-CCCCTAs and two grounded capacitors without any passive resistors. All input voltage nodes and output current node are high impedance which is cascadable without the need of any buffer devices. Five second order filtering types are obtained in the network. The filtering parameters including the natural frequency (ω
0
), quality factor (Q) and pass band gain are electronically controlled. In addition, the Q is also electronically controlled without disturbing the ω
0
. The PSpice simulations using the model process parameters of the NR100N (NPN) and PR100N (PNP) bipolar transistor arrays ALA400CBIC-R from AT&T are given to investigate the characteristics of the proposed active filter.