Ali Toker

Current-mode all-pass filters using current differencing buffered amplifier and a new high-Q bandpass filter configuration

A new configuration realizing first-order canonical current processing all-pass filters based on current differencing buffered amplifier, a recently introduced active element, is proposed. Using this configuration, two types of first-order current-mode all-pass filters are derived. They employ only a single active element and a bare minimum number of passive components. No component-matching constrains are required. Because of the high performance of the current differencing buffered amplifier, they are suitable for wideband applications. The derived filters are cascadable because of their high output impedances and they use fewer active and/or passive components compared to their previously reported counterparts. As an application of the proposed first-order all-pass networks, a new current-mode high-Q bandpass filter, which offers a number of advantages over its counterparts, is also given.

The dual-X current conveyor (DXCCII): a new active device for tunable continuous-time filters

In this work, a new active device, namely the dual-X current conveyor is proposed for linear tunable continuous-time filtering. The proposed device avails tunability with the aid of triode MOSFETs, while keeping large-signal linearity high. Besides linearity enhancement, the dual-X structure of the active device brings interesting features, which help reduce the required number of active devices and MOSFET resistors in a MOSFET-C continuous-time filter. Also, unlike most MOSFET-C filter structures, there does not exist a matching requirement for the utilized MOSFETs. A CMOS implementation and two application examples (a current mode Tow-Thomas biquad and a current-mode sinusoidal oscillator) are supplied and simulated to reveal the important advantages.

Current-Mode High Output Impedance Sinusoidal Oscillator Configuration Employing Single FTFN

In this study, a general current-mode high output impedance sinusoidal oscillator configuration is proposed. The proposed oscillator configuration uses a single four terminal floating nullor (FTFN), two capacitors and five resistors. The oscillator configuration exhibits high output impedance which makes easy to drive loads without using any buffering devices and provide non-interactive control of oscillation condition and oscillation frequency. The proposed topology also yields single frequency oscillators with reduced number of passive components. All of the proposed oscillators permit good frequency stability and exhibit low active and passive sensitivities. Theoretical analysis is verified with experimental results.

Single resistance-controlled sinusoidal oscillators employing current differencing buffered amplifier

Abstract The basic aim of this paper is to present several of a newly introduced current differencing buffered amplifier (CDBA)-based oscillator topologies achieving orthogonal control of oscillation condition b and oscillation frequency ω 0 with a reduced number of components. A single resistor is used for adjusting their frequency, and further, this resistance is grounded, which is important from the integration point of view. Taking these considerations into account they are very suitable for voltage-controlled oscillator (VCO) implementation.

Insensitive current-mode universal filter using dual output current conveyors

A new current-mode universal filter with single input and three outputs employing only three dual output current conveyors and five grounded passive elements is presented. The proposed filter realizes three filter functions simultaneously, all at high impedance outputs. No component matching is required and all the passive and active sensitivities are low. Furthermore, the filter can also realize the notch and all-pass responses. Orthogonal control of the natural angular frequency and the quality factor is achieved.

High-output-impedance transadmittance type continuous-time multifunction filter with minimum active elements

A new transadmittance multifunction filter with single input and three outputs employing only three positive-type second-generation current conveyors and five passive elements is presented. The proposed filter realizes three basic filter functions simultaneously, all at high impedance outputs. No component matching is required and all the passive sensitivities are low. Experimental verification is also performed.

On the realization of oscillators using state equations

Summary In this work, an extension to the oscillator synthesis method using the state variable technique is presented. It is shown that using suitable block diagrams, which represent the state equations, systematic circuit realizations can be performed. The most critical steps of the presented method are the selection of the suitable characteristic equation and thederivation of the corresponding sub-circuits. The selection criteria of thecharacteristic equations for the realization of single resistance controlled oscillators (SRCOs) are also given. By using the extended state variable synthesis method, SRCOs employing a single current feedback amplifier (CFA)are obtained. Furthermore, a new active element, namely the differentialvoltage current feedback amplifier (DVCFA) is proposed for the realization of oscillators employing only grounded capacitors and new SRCOs employing thisactive element are presented. SPICE simulations and experimental results confirm the operation of the presented oscillators.

Universal immittance function simulators using current conveyors

Abstract A new method for the realisation of parallel connection of inductance, capacitance and resistance using only positive type second-generation current conveyors is presented. All circuits obtained using the proposed method exhibit equivalent input admittance functions. For these circuits no element matching conditions are imposed, the simulated immittance values can orthogonally be adjusted both for positive and negative values. The circuits employ only grounded passive components. The functionality of some of the circuits is preserved at relatively high frequencies, illustrated by simulation, a property which cannot be expected from classical voltage mode op-amps realisations.

A New All-pass Section for High-Performance Signal Processing with a Single CCII–

This paper presents a new all-pass section (APS) employing a negative-type second-generation current conveyor (CCII-), two resistors and a grounded capacitor, which is important from the integrated circuit (1C) implementation point of view. The use of the grounded capacitor allows the 1C implementation with standard CMOS technologies. This circuit is also suitable for the realization by using current controlled current conveyor (CCCII) as active element. In this case the current-controlled intrinsic x-terminal resistance of the conveyor realizes one resistor and the circuit employs only one external resistor and one grounded capacitor. The proposed circuit is verified with SPICE simulations and experimental results. bersicht Die Arbeit stellt eine neue Allpa -Schaltung (APS) vor, die aus einem Current-Conveyor vom Minus-Typ der zweiten Generation (CCII-) sowie aus zwei Widerst nden und einem einseitig geerdeten Kondensator besteht. Letzteres ist aus Sicht der Implementierung in integrierte Schaltungen (1C) wichtig und erlaubt die Verwendung standardisierter CMOS-Technologien. Die Schaltung kann ebenso mit einem stromgesteuerten Current-Conveyor (CCCII) als aktives Element realisiert werden. Hierbei wird der stromgesteuerte intrinsische Widerstand des x-Ausgangs des Conveyors verwendet, so da neben dem Kondensator nur noch ein Widerstand ben tigt wird. Die vorgeschlagene Schaltung wurde mit dem Programm SPICE simuliert und me technisch gepr ft F r die Dokumentation Allpass / CMOS-Technologie / Current-Conveyor Frequenz 57(2003) 11-12

New current-mode universal filters using only four (CCII+)s

Two new single-input three-output current-mode (CM) universal filters using only four CCIIs of plus-type were presented. It was shown that both filters have simpler implementations compared to the current conveyor-based universal current filters already known in the literature. Experimental results verifying theoretical analyses are also included.