|Autors: Pandiev, I. M.|
Title: Realization of programmable nth-order universal filter using four-terminal CFOAs
Keywords: Analog circuits; nth-order filters; Active-RC integrators; CFOAs; CDBAs; Digital potentiometers
Abstract: In this paper a general structure for realizing programmable nth-order universal active-RC filter is presented. The proposed circuit performing standard low-pass (LP), high-pass (HP), band-pass (BP) and band-reject (BR) transfer functions, employs four-terminal current-feedback operational amplifiers (CFOAs), grounded or virtually grounded passive components and digital potentiometers. The fourterminal CFOAs are a special type of monolithic operational amplifiers and can be represented as a cascade structure of positive second-generation current conveyor (CCII+) and an additional unity-gain voltage buffer. The pole frequency of the filter can be adjusted electronically and independently from the tuning of the other parameters in wide range via controllable digital code of the digital potentiometers. The workability of the proposed active-RC filter has been demonstrated by PSpice simulation results.
Вид: публикация в международен форум, публикация в реферирано издание