Solutions of reconnection-less OTA-based biquads with electronical transfer response reconfiguration

This contribution deals with special second-order (biquadratic) single-input and single-output filtering structures employing operational transconductance amplifiers (OTAs) for various electronic variation of parameters that leads to reconnection-less transfer response and is tunable. Structures allows change of transfer type between several types of responses (all or some of them) particularly high-pass, all-pass, band-reject, band-pass and low-pass and high-pass response with intended zero in transfer function. PSpice simulations with models of commercially available real devices support theoretical presumptions.