Current-mode KHN-equivalent biquad using CDBAs

A new Kerwin-Huelsman-Newcomb (KHN)-equivalent biquad, operating in the current mode (CM), is proposed. The proposed circuit is derived from the adjoint graph of the signal flow graph corresponding to the classical KHN circuit. The derived circuit is a CM universal filter, which offers all the main advantages of CM circuits as well as those of the classical KHN circuit. The proposed circuit employs three current differencing buffered amplifiers (CDBAs) as active elements. In addition to the three basic filter responses, it also allows the realisation of the notch and allpass responses without requiring any element matching conditions.