Electronically Controllable SITO Multifunction Filter with Single VDTA

This paper presents a modern second-order multifunction filter with single input and triple output terminals employing only single VDTA and four passive elements. It is capable of generating the three standard biquadratic filtering functions, namely lowpass (LP), bandpass (BP) and highpass (HP) responses, simultaneously from the same topology. The circuit also offers the advantage of an electronic adjusting of the natural angular frequency (ω
_o
) and the quality factor (Q) through the VDTA's transconductance gains. The tracking error effects on the performance of the proposed filter are essayed. PSPICE simulations of the presented filter are performed based on TSMC 0.25-μm CMOS technology.