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A new voltage-mode (VM) biquad filter is presented, which employs four Current Conveyors (CC) along with five resistors and only two grounded capacitors, facilitates electronic control of filter parameters through grounded resistors (realizable by FETs/MOSFETs) and is suitable for IC implementation in bipolar or CMOS technology. The circuit offers several advantages over the four-CC-based VM biquads published earlier. The workability of the new circuit has been confirmed by PSPICE simulations.

This letter shows how, by simple modifications, the four-current-conveyor (CC) voltage mode biquad filter recently proposed by Singh and Senani provides dual function capability, i.e., the same circuit also yields all the five current-mode (CM) filters.

Circuits for realizing floating capacitors using grounded capacitors and current conveyors are described. The effect of all the nonidealities of the various current conveyors on the realized impedances has been analyzed in detail.

Variable gain Current Conveyors have been proposed to allow control of the value on fixed resistors. In this paper, procedures will be described, taking into account the stability of different configurations when a practical CCII^- is applied. Correction circuits will modify the control range. Frequency response and transients are shown.

A new current-mode band-pass filter using the inverting second-generation current conveyor (ICCII) is introduced. The circuit is generated from a frequency-dependent negative resistance (FDNR)-C circuit realized using ICCII+. It is observed that a voltage-mode band-pass filter using two CCII+ has similar transfer function to this current-mode filter. The adjoint network theorem is used to demonstrate the transformation between the two circuits. Two new voltage-mode grounded capacitor band-pass filters using two ICCII are also introduced. The first voltage-mode circuit is generated from the FDNR-C circuit and employs two opposite Z polarity ICCII. The second voltage-mode circuit is obtained from the first circuit by relocation of the input and a grounded terminal. Two new additional grounded capacitor and grounded resistor current-mode band-pass filters with independent control on the filter Q are also introduced. Spice simulation results with 0.35 μm CMOS transistors model are included to demonstrate the practicality of the two ICCII- band-pass current-mode filter.

A new voltage-mode biquad with four inputs and four outputs using only two differential difference current conveyors (DDCCs), two grounded capacitors, and two resistors is proposed. The proposed circuit can act as a multifunction voltage-mode filter with one or three inputs and four outputs and can perform simultaneous realization of voltage-mode notch, highpass, bandpass, and lowpass filter signals from the four output terminals, respectively, without any component choice conditions. On the other hand, it also can act as a universal voltage-mode filter with four inputs and a single output and can realize five generic voltage-mode filter signals from the same configuration without any component-matching conditions. Finally, to verify our architecture, we have designed this analog filter chip with TSMC 0.35 μm 2P4M CMOS technology. This chip operates to 1.125 MHz and consumes 30.95 mW. The chip area of the analog filter is about 0.822 mm².

New voltage mode and current mode active RC Bode-type variable equalizers using current conveyors are introduced. The proposed equalizers can operate at much higher frequencies than the classical operational amplifier-based variable equalizers. Spice simulation results are included to confirm the practicality of the proposed circuits.

In this paper, eight new Frequency Dependent Negative Resistance (FDNR) circuits using two current conveyors or inverting current conveyors or a combination of the two types are introduced. The proposed circuits are canonic and they use two grounded capacitors and one floating resistor. The generation of grounded capacitor minimum passive component oscillators from the FDNR circuits is also considered. It is found that two of the recently reported attractive oscillators are among the family of the generated oscillator circuits. Additional six new oscillator circuits based on the FDNR circuits are introduced in this paper. Spice simulation results using technology: SCN 05 feature size 0.5 μm, MOSIS Vendor: AGILENT to demonstrate the practicality of the proposed oscillators are included.

In this paper, three dual-mode (mixed-mode) analog filters using only grounded capacitors and two to three second-generation current conveyors (CCIIs) are presented. The first proposed filter can provide a transimpedance-mode (TIM) second-order filter transfer function (TF), and is free from passive component matching constraints, which is advantageous in integrated circuit (IC) design. Other two mixed-mode filters having the property of tunability are derived from the first proposed filter. However, the developed filters in this work, like other active filters, suffer from nonidealities such as nonideal gain and parasitic impedance effects which increase the order of the filter TFs; accordingly, stability problem may arise. In this study, stability analysis using gain and phase margins is accomplished. To explain the claimed ideas, several computer simulations and an experimental test are performed.

A fully cascadable (i.e., low/high input impedance for current/voltage input signals and high/low output impedance for current/voltage output signals) mixed-mode (input and output signals can be voltage or current) universal filter biquad by using three differential difference current conveyors (DDCCs), three grounded resistors, and two grounded capacitors is presented in this paper. The proposed biquad can realize the inverting, non-inverting, and differential types universal filtering responses (lowpass, highpass, bandpass, notch, and allpass) from the voltage and current output terminals without changing the filter topology. The proposed circuit is suitable for cascading in all the four possible modes (i.e., voltage, current, transresistance, and transconductance modes). Moreover, the proposed mixed-mode biquad still enjoys (i) using only grounded passive components, (ii) no need of extra inverting and non-inverting amplifiers for special input signals, and (iii) low active and passive sensitivities. This paper also shows how analytical synthesis can be used to produce the proposed mixed-mode filter circuit. H-Spice simulation results confirm the theory.

A novel versatile three-input five-output universal voltage-mode filter employing two differential difference current conveyors, two grounded capacitors and three resistors is proposed. The proposed configuration can be used as either a single-input five-output or three-input two-output. Unlike the previously reported works, it can simultaneously realize five different generic signals: low-pass, band-pass, high-pass, notch and all-pass. Moreover, the proposed circuit still offers the following advantages: (i) the employment of two grounded capacitors, (ii) no need to employ inverting-type input signals, (iii) no need to impose component choice, (iv) orthogonal control of the resonance angular frequency ω_o and the quality factor Q and (v) low active and passive sensitivity performances.

A systematic synthesis procedure for generating third-order grounded passive element quadrature oscillators is given. The synthesis procedure is based on using nodal admittance matrix (NAM) expansion applied to the Y matrix of a recently reported three Op Amp third-order oscillator circuit. Four new circuits using current conveyors (CCII) are reported. In addition four more new circuits using inverting current conveyors (ICCII) are also given. Many more quadrature third-order oscillator circuits using combinations of CCII and ICCII can be obtained. Simulation results demonstrating the practicality of one of the generated circuits are included.

To extend the existing knowledge on first-order voltage-mode all-pass filters, this paper presents two novel first-order voltage-mode all-pass sections, each employing single fully differential second-generation current conveyor (FDCCII) being used as the newly obtained fully differential voltage conveyor (FDVC), a resistor and a grounded capacitor. Both the proposed circuits possess high-input and low-output impedance feature, which makes the proposed circuits ideal for voltage-mode systems. Non-ideal study along with simulation results is given for validation.

This paper presents a voltage-mode (VM) tunable all-pass section, employing a grounded capacitor and a newly introduced current conveyor with an extra X stage. The proposed all-pass filter uses grounded capacitor as the only passive component and benefits from high input and low output impedance. The proposed circuit exhibits eight performance features without trade-offs, as compared to carefully chosen 25 published works. The functionality of the proposed element is verified through PSPICE simulation using 0.25-μm process parameters. An application of second order is also incorporated.

A new cascadable voltage-input, current-output first-order all-pass filter and its applications in second-order filter and oscillator are presented. The proposed circuit employs a single active element namely extra-X current-controlled current conveyor (EX-CCCII) and only a single grounded capacitor. The circuit exhibits high input and high output impedances, so that the filter can be cascaded without additional buffers. The pole frequency is electronically tunable and the circuit requires no component matching constraints. Effects of nonidealities and parasitics are also discussed. As applications, a second-order transadmittance (TA)-mode all-pass filter and a quadrature oscillator are also realized using the proposed voltage-input, current-output first-order all-pass filter. These examples validate easy cascading feature of the proposed circuit. The validity of the proposed circuit is verified through PSPICE simulations using 0.25$\mu$m parameters with a supply voltage of $\pm 1.25$V.

Experimental results of a SPICE-compatible macromodel to model the nonlinear behavior of second generation current conveyors (CCIIs) at low frequency are presented. The derived macromodel includes not only those real physical performance parameters more important for CCII like the dynamic range, slew rate, DC gain and gain–bandwidth product, but parasitic resistors and capacitors associated to the input and output terminals are also included. To validate the derived macromodel, a saturated nonlinear function series (SNFS) was built by using AD844AN commercially available active device configured as CCII and embedded in a chaotic system. After that, an experimentally generated chaotic signal was applied as excitation signal to SNFS built with AD844AN foundry-provided macromodel and the proposed herein. Our results indicate that the derived macromodel can be used in the time-domain for forecasting the behavior of nonlinear circuits without worsening the accuracy and at less time compared with the foundry-provided macromodel.

The paper presents a simple circuit for the realization of two digital modulation schemes: BPSK and ASK simultaneously, with the advantage of high input impedance at the signal input nodes and use of grounded resistors. The new circuits are based on the use of extra-$X$ current conveyor. Detailed analysis is given and circuit verification is carried out through simulations with a supply voltage of $\pm 1.25$V and $0.25\mu$m CMOS parameters to support the proposed circuit. Nonideal study is also given. An extended application of the circuit in realizing precision half-wave and full-wave rectifiers is further proposed by incorporating a simple modification to the proposed topology. The new proposed CMOS compatible electronic circuits enrich the utility of extra-$X$ current conveyor for realizing diverse electronic functions.

This paper presents first-order voltage-mode filters using a single current conveyor with an additional X-stage, and passive elements. The new circuits have multifunction capability, and also realize low-shelf, high-shelf and band-shelf functions. The study is carried out on the effects of non-idealities, parasitic elements, and loading on the performance of proposed circuits. Active and passive sensitivities are also analyzed. The active element, extra-X current conveyor used for designing new circuits is simpler than most of the one active element and two passive elements’ based circuits. Detailed comparisons are carried out with relevant available works, and the new circuits are found to be more compact and exhibit higher frequency performances. The simulation results using 0.25$\mu$m CMOS parameters with $\pm$1.25V power-supply are shown to verify the proposed circuits. The proposed circuits are also verified through simulations. Experimental support is given using AD-844 ICs to strengthen the validity of the proposed circuits.

This paper presents a new polar logic circuit using a single current conveyor, two MOS switches and two resistors in each case. Thus, polar NAND and NOR circuits are proposed. The circuits’ operation details and simulation results are given in support of the proposed theory. The circuits are designed using CMOS CCII$+$ with ±2 V supply voltage. The polar logic levels at the output are −1 and 1 V for logic 0 and 1, respectively. The gates’ functioning for capacitive loading is also tested. The new circuits are expected to be useful in digital and communication systems.