Design of CDBA-based active polyphase filter for low-IF receiver applications

A novel first-order active-RC polyphase filter section, using current differencing buffered amplifiers (CDBAs), is presented. The section uses 6 resistors, 2 capacitors, and 2 CDBAs. The transfer function of the proposed section has a single pole and optionally a single zero. Increasing the number of cascading sections, any higher order polyphase filter can be realized. This paper also introduces the leakage caused by element deviation and the effects of the amplifier in nonideal cases. Furthermore, nonideal performances of the proposed filter section are tested with PSpice simulations.