Pseudo-Differential Electronically Controllable Second-Order Band-Pass Filter Using Modified Current Differencing/Summing Units

This paper presents synthesis of analogue frequency filter with differential input and differential output terminals. The inner structure of the filter has single-ended form, i.e. filter behaves as so-called pseudo-differential circuit. Active elements of the filter are Differential Voltage Buffer (DVB) as an input stage and Modified Current Differencing Unit (MCDU) together with Modified Current Summing Unit (MCSU) as inner and also output stage. All important parameters (angular frequency, quality factor, pass-band gain) of the filter are electronically controllable by parameters of these active elements. The proposed topology operates at voltage mode and has high input impedance. Expected behaviour of the filter is analyzed and verified by PSpice simulations using CMOS models of above mentioned active elements.