Resistorless realization of electronically tunable voltage-mode SIFO-type universal filter

In this work, an electronically tunable universal voltage-mode biquadratic filter with single input and five outputs is introduced. The proposed filter structure only employs three differential difference current conveyor transconductance amplifiers (DDCCTAs) and two grounded capacitors without needing any external passive resistor. All the five standard biquadratic filter functions; lowpass, bandpass, highpass, bandstop and allpass, can be realized simultaneously without imposing component choice and changing circuit configuration. In addition, the circuit also features the high-input impedance terminal, and provides an orthogonal electronic control of its natural angular frequency (ω0) and quality factor (Q) by adjusting only bias currents of the DDCCTAs for the fixed values of capacitors.