|Autors: Pandiev, I. M.|
Title: Voltage-mode lowpass, bandpass, and bandstop programmable filter using four-terminal CFOAs
Keywords: Analogue circuits, Active-RC filters, Four-terminal CFOAs, CCII+s.
Abstract: In this paper a voltage-mode programmable active-RC filter employing four Current-Feedback Operational Amplifiers (CFOAs), one dual CMOS digital potentiometer, seven virtually grounded resistors and two grounded capacitors is presented. The presented active-RC filter is the result of a systematic circuit synthesis and can comparatively easily be derived from the VFOA-based Fleischer-Laker (FL) Switched Capacitor (SC) biquad stage, providing lowpass, bandpass and bandstop responses. The proposed circuit offers the following advantages: (1) realization of lowpass, bandpass and bandstop (notch) responses from the same configuration, (2) orthogonal digital control of the natural frequency and the quality factor by grounded resistors, (3) the use of two grounded capacitors which is not the case in the FL circuit, (4) low active and passive sensitivities and (5) low output impedance. The workability of the new active- RC filter has been demonstrated by PSpice simulation results.
Вид: публикация в международен форум, публикация в реферирано издание