An Independently/Electronically Tunable Voltage-mode Multi-function Filter Using VDGAs

A three-input single-output multi-function filter based on voltage differencing gain amplifiers (VDGAs) as active devices is introduced. The proposed circuit consists of 3 VDGAs and 2 capacitors, without any resistor, suitable to implement into integrated circuit architecture. The proposed circuit can provide 5 standard filter functions including lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass filter (AP) without changing structure. The outstanding feature of the mentioned filter is that the natural angular frequency (ω
_o
) and quality factor (Q) can be controlled independently through transconductances of the VDGAs. The total power consumption of proposed circuit is 0.82mW.