New Universal Current-mode Biquad Using Only Three ZC-CFTAs

The objective of this paper is to present a new universal Current-mode biquad capable of providing all the five basic filter functions, namely, low pass (LP), Band pass (BP), high pass (HP), Band reject (BR) and all pass (AP) from the same configuration using only three Z - copy current follower transconductance amplifiers (ZC-CFTA) along with the provision of independent electronic tunability of the filter parameters f0 and Q0 (or bandwidth) through two separate DC bias currents while employing both grounded capacitors as desirable for integrated circuit implementation. The workability of the proposed structure is verified by PSPICE simulations based on CMOS implementation of the ZC-CFTA

Canonic Realizations of Voltage-Controlled Floating Inductors Using CFOAs and Analog Multipliers

Abstract New voltage-controlled floating inductors employing CFOAs and an analog multiplier have been presented which have the attractive features of using a canonic number of passive components (only two resistors and a capacitor) and not requiring any component-matching conditions and design constraints for the intended type of inductance realization. The workability and applications of the new circuits have been demonstrated by SPICE simulation and hardware experimental results based upon AD844-type CFOAs and AD633-type/MPY534 type analog multipliers

Inverse Analog Filters: History, Progress and Unresolved Issues

This paper traces the history of the evolution of inverse analog filters (IAF) and presents a review of the progress made in this area to date. The paper, thus, presents the current state-of-the art of IAFs by providing an appraisal of a variety of realizations of IAFs using commercially available active building blocks (ABB), such as operational amplifiers (Op-amp), operational transconductance amplifiers (OTA), current conveyors (CC) and current feedback operational amplifiers (CFOA) as well as those realized with newer active building blocks of more recent origin, such as operational transresistance amplifiers (OTRA), current differencing buffered amplifiers (CDBA) and variants of current conveyors which, although not available as off-the-shelf ICs yet, can be implemented as complementary metal–oxide–semiconductors (CMOS) or be realized in discrete form using other commercially available integrated circuits (IC). In the end, some issues related to IAFs have been highlighted which need further investigation

Inverse Analog Filters: History, Progress and Unresolved Issues

This paper traces the history of the evolution of inverse analog filters (IAF) and presents a review of the progress made in this area to date. The paper, thus, presents the current state-of-the art of IAFs by providing an appraisal of a variety of realizations of IAFs using commercially available active building blocks (ABB), such as operational amplifiers (Op-amp), operational transconductance amplifiers (OTA), current conveyors (CC) and current feedback operational amplifiers (CFOA) as well as those realized with newer active building blocks of more recent origin, such as operational transresistance amplifiers (OTRA), current differencing buffered amplifiers (CDBA) and variants of current conveyors which, although not available as off-the-shelf ICs yet, can be implemented as complementary metal–oxide–semiconductors (CMOS) or be realized in discrete form using other commercially available integrated circuits (IC). In the end, some issues related to IAFs have been highlighted which need further investigation

ERRATA: OTRA-Based Multi-Function Inverse Filter Configuration

In the article published by mentioned authors with DOI:10.15598/aeee.v15i5.2572 were found accidental errors in four references. These errors were caused by human factor and deficient communication between the authors and publisher. Correction is published on the basis of the author’s request. The editorial members of Advances in Electrical and Electronic Engineering apologize to the authors and readers of the journal for not detecting the problem with references during the publication process

OTRA-Based Multi-Function Inverse Filter Configuration

A new OTRA-based multifunction Inverse filter configuration is presented which is capable of realizing low pass, high pass and band pass filters using only two OTRAs and five to six passive elements. To the best knowledge of the authors, any inverse filter configuration using OTRAs has not been reported in the literature earlier. The effect of the major parasitics of the OTRAs and their effect on the performance filter have been investigated and measured through simulation results and Monte-Carlo analysis. The workability of the proposed circuits has been confirmed by SPICE simulations using CMOS-based-OTRA realizable in 0.18 µm CMOS technology. The proposed circuits are the only ones which provide simultaneously the following features: use of reasonable number of active elements (only 2), realizability of all the three basic filter functions, employment of all virtually grounded resistors and capacitors and tunability of all filter parameters (except gain factor, H_0 for inverse high pass). The centre/cut-off frequency of the various filter circuits lying in the vicinity of 1 MHz have been found to be realizable, which has been verified through SPICE simulation results and have been found to be in good agreement with the theoretical results

Current conveyors: variants, applications and hardware implementations

This book serves as a single-source reference to Current Conveyors and their use in modern Analog Circuit Design. The authors describe the various types of current conveyors discovered over the past 45 years, details of all currently available, off-the-shelf integrated circuit current conveyors, and implementations of current conveyors using other, off-the-shelf IC building blocks. Coverage includes prominent bipolar/CMOS/Bi-CMOS architectures of current conveyors, as well as all varieties of starting from third generation current conveyors to universal current conveyors, their implementations and applications. •Describes all commercially available off-the-shelf IC current conveyors, as well as hardware implementations of current conveyors using other off-the-shelf ICs; • Describes numerous variants of current conveyors evolved over the past forty five years; • Describes a number of Bipolar/CMOS/Bi-CMOS architectures of current conveyors, along with their characteristic features; • Includes a comprehensive collection of over 400 application circuits using current conveyors; • Provides an exhaustive catalogue of current conveyor-based circuits for a variety of applications, including instrumentation amplifiers, precision rectifiers, simulated inductors, filters, sinusoidal oscillators, waveform generators, chaos generators, analog multipliers/dividers, memristive emulators and numerous others

Generation of equivalent forms of operational trans-conductance amplifier-RC sinusoidal oscillators: the nullor approach

It has been shown in two earlier papers published from this study that corresponding to a given single-operational trans-conductance amplifier (single-OTA)-RC and dual-OTA-RC sinusoidal oscillators, there are three other structurally distinct equivalent forms having the same characteristic equation, one of which employs both grounded capacitors (GC). In this study, an earlier nullor-based theory of generating equivalent op-amp oscillator circuits, proposed by the first author, is extended to derive equivalent OTA-RC circuits which discloses the existence of an additional number of equivalent forms for the same given OTA-RC oscillators than those predicted by the quoted earlier works, and thereby considerably enlarging the set of equivalents of a given OTA-RC oscillator. Furthermore, the presented nullor-based theory of generating equivalent OTA-RC oscillators results in three additional interesting outcomes: (i) the revelation that corresponding to any given OTA-RC oscillator there are two ‘both-GC’ oscillators (and not merely one, as derived in the quoted earlier works); (ii) the availability of explicit current outputs in several of the derived equivalents and (iii) the realisability explicit-current-output ‘quadrature oscillators’ in some of the generated equivalent oscillators. The workability of the generated equivalent OTA-RC oscillators has been verified by SPICE simulations, based on CMOS OTAs using 0.18 µm CMOS technology process parameters, and some sample results are given