Adjoint-KHN Equivalent Realization of Current Mode Universal Biquad Employing Third Generation Current Conveyor

Abstract

The classical “Kerwin-Huelsman-Newcomb” (KHN) filter has been a very popular high performance multifunction biquadratic analog filter. Derived from the adjoint signal flow graph of this KHN circuit a new multi-input universal filter has been presented utilising for the first time all third generation current conveyors. This new universal biquadratic filter employs all grounded passive elements, realizes all the standard five filtering functions namely “Low pass”, “High pass”, “Band pass”, “Band reject” and “All pass” and produces all the outputs without requiring any additional active and /or passive component. The workability of the proposed circuit configuration has been verified by PSPICE simulation along with its non-ideal analysis, time domain analysis, sensitivity analysis and Monte-Carlo analysis. The proposed universal filter with explicit current output may be suitably employed in all current-mode application situations of classical KHN filter such as; FM demodulators, phase-locked-loops etc. Keywords: Active Filters, Analog Processing Circuits, Biquadratic Filters, Biquadratic Functions, Current conveyors