Tunable fully-differential filter employing MOTA and DACA elements

Abstract

A new fully-differential (F-D) filtering structure of the 2nd-order current-mode universal filter is described in this paper. Presented filter is also proposed in a single-ended (S-E) form in order to compare behavior of single-ended and fully-differential structures. Signal-flow graphs method is used to design both presented filters. Multi-output transconductance amplifiers (MOTAs), digitally adjustable current amplifier (DACA), multi-output current follower (MO-CF) and fully differential current follower (FD-CF) were used in proposal. Filters possess of ability to adjust their pole frequency and quality factor independently of each other. The actual function of proposed filters has been verified by PSpice simulations and experimental measurements.A new fully-differential (F-D) filtering structure of the 2nd-order current-mode universal filter is described in this paper. Presented filter is also proposed in a single-ended (S-E) form in order to compare behavior of single-ended and fully-differential structures. Signal-flow graphs method is used to design both presented filters. Multi-output transconductance amplifiers (MOTAs), digitally adjustable current amplifier (DACA), multi-output current follower (MO-CF) and fully differential current follower (FD-CF) were used in proposal. Filters possess of ability to adjust their pole frequency and quality factor independently of each other. The actual function of proposed filters has been verified by PSpice simulations and experimental measurements.