Analytical synthesis of voltage mode OTA-C all-pass filters for high frequency operation

This paper describes how analytical synthesis facilitates the development of new voltage mode Operational Transconductance Amplifiers and Capacitors or (OTA-C) all-pass filters suitable for high-frequency operation. The proposed synthesis method is based on the analytical solution of a single, nth-order filter transfer function and the generation of n realizable transfer functions implemented using lossless integrators and one additional constraint. The presented all-pass filters contain the least number of passive and active elements for a given filter order when compared with previous work. Furthermore, the method generates circuits that contain only grounded capacitors and single-input OTAs, attractive features for high-frequency applications.