Systematic Derivation for Quadrature Oscillators Using CCCCTAs

According to 16 nullor-mirror models of the current-controlled current conveyor transconductance amplifier (CCCCTA) and using nodal admittance matrix (NAM) expansion method, three different classes of the double-mode quadrature oscillators employed CCCCTAs and two grounded capacitors are synthesized. The class I oscillators have 32 different forms, the class II oscillators have 16 different forms, and the class III oscillators have four different forms. In all, 52 quadrature oscillators using CCCCTAs are obtained. Having used canonic number of components, the circuits are easy to be integrated and the condition for oscillation and the frequency of oscillation can be tuned by tuning bias currents of the CCCCTAs. The circuit analysis and simulation results have been included to support the generation method

Current-Mode Sixth-Order Elliptic Band-Pass Filter Using MCDTAs

In this paper, a modified CDTA (MCDTA) is presented and the current-mode second-order band-pass, high-pass notch, and low-pass notch circuits using MCDTAs are given. Moreover, a current-mode sixth-order elliptic band-pass filter is realized by means of cascade method. Having used six MCDTAs, six grounded capacitors and two resistors, the circuit is easy to be integrated, of which the parameters can be electronically adjusted by tuning bias currents. It is noted that the results of circuit simulations are in agreement with theory

Single-Input Five-Output Electronically Tunable Current-Mode Biquad Consisting of Only ZC-CFTAs and Grounded Capacitors

This paper presents an electronically tunable current-mode biquadratic filter constructing with four Z-copy current follower transconductance amplifiers (ZC-CFTAs) and only two grounded capacitors. The presented filter can realize all the five standard biquadratic functions simultaneously without requiring any component matching conditions and connecting any relevant output currents. The circuit has one low-impedance input and five high-impedance outputs, resulting in easy cascadability in current-mode. Also, the developed circuit exhibits the advantage of non-interactive electronic control of the natural angular frequency and the quality factor Q along with low incremental active and passive sensitivities. Computer simulation results using PSPICE program are given to confirm the validity of the theoretical prediction and to point out the attractive performance of the circuit

Current Gain Controlled CCTA and its Application in Quadrature Oscillator and Direct Frequency Modulator

A modified conception of adjustable current conveyor transconductance amplifier (CCTA) and its interesting application in simple quadrature oscillator expandable for direct frequency modulation purposes, employing only four grounded passive elements is presented in this paper. It is quite simple solution for modern communication subsystem components. An electronic adjusting of the oscillation frequency is easily possible and control of condition of the oscillation is realized via only one grounded resistor. The characteristic equation, condition of oscillation and major parasitic influences of real active part are discussed. The verification includes PSpice simulation and measurement with the CCTA block formed by commercially available active elements

Realization of electronically tunable voltage-mode/current-mode quadrature sinusoidal oscillator using ZC-CG-CDBA

a b s t r a c t This paper presents a first of its kind canonic realization of active RC (ARC) sinusoidal oscillator with non-interactive/independent tuning laws, which simultaneously provides buffered quadrature voltage outputs and explicit quadrature current outputs. The proposed circuit is created using a new active building block, namely the Z-copy controlled-gain current differencing buffered amplifier (ZC-CG-CDBA). The circuit uses three resistors and two grounded capacitors, and provides independent/non-interactive control of the condition of oscillation (CO) and the frequency of oscillation (FO) by means of different resistors. Other advantageous features of the circuit are the inherent electronic tunability of the FO via controlling current gains of the active elements and the suitability to be employed as a low-frequency oscillator. A non-ideal analysis of the circuit is carried out and experimental results verifying the workability of the proposed circuit are included