Current-mode active-only universal filter

A new current-mode active-only universal filter based on and employing two OA's and three DOOTAs is presented. The circuit is capable of realizing all the five generic filter characteristics viz. Lowpass, bandpass, highpass, notch and allpass without changing the circuit topology or nature of components, or additional component besides, no component matching conditions is required. The filter parameters omega(o) and Q are electronically tunable in an orthogonal manner through separate transconductances of OTAs. The circuit has low sensitivity performance and is ideal for production in IC form as it is devoid of external passive components.