Dual-Mode Multifunction Filter Using VDGAs

An electronically controllable resistorless dual-mode multifunction filter applying two voltage differencing gain amplifier (VDGA) and three external capacitors is presented. The displayed circuit can perform either voltage-mode filter or current-mode filter from the same structure. The circuit demonstrates the ensuing advantageous features: (i) simultaneous realization of highpass (HP), bandpass (BP) and lowpass (LP) filter functions, (ii) no requirement for element matching constraints, (iii) electronic tuning of its major parameters, (iv) low sensitivity performance. The simulation results affirm the workability of the presented circuit.