A General Class Of Voltage-Mode And Current-Mode Active-Only Filters

This paper presents voltage-mode and current-mode capacitorless and resistorless filters with a general class of circuit transfer functions using only operational amplifiers (OAs) and operational transconductance amplifiers (OTAs). The proposed circuits can realize various high-order circuit characteristics by a suitable choice of the current outputs of the OTAs. The circuit characteristics can be electronically tuned through adjustment of the transconductance gains of the OTAs. The cascade realizations of high-order filters are also discussed, using the proposed configurations. Some examples are given, together with simulated results by PSPICE. The circuit configurations are very suitable for implementation in both bipolar and CMOS technologies.