The main object of this brief report is to introduce 14 new floating immittance (FI) configurations each employing only two current feedback op-amps (CFOA) and canonical number of only three passive elements, as an addition to the seven such circuits known earlier. The results of some SPICE simulations and hardware experimental results, based on the commercially available AD844-type integrated circuit CFOAs, have been given to demonstrate the workability of the presented new FI circuits.

ABSTRACT Although a large number of new active building blocks have been employed in recent literature, the second‐generation voltage conveyor (VCII) is receiving prominent attention due to its current processing capability coupled with a low output impedance, thereby making it suitable for both current mode and voltage mode signal processing and signal generation applications. Consequently, a variety of configurations for realizing the mentioned functions in voltage mode (VM) have been presented in the literature. The object of this paper is, therefore, to present three new configurations using VCIIs, which realize voltage‐mode fully uncoupled sinusoidal oscillators, two of which offer quadrature outputs. The workability of the suggested circuits has been demonstrated through PSPICE simulation results using CMOS‐based VCIIs implemented in 0.18‐μm TSMC technology parameters along with hardware‐based testing, wherein VCIIs are implemented through off‐the‐shelf available ICs AD844.

This communication introduces a new active circuit configuration realized with only two current feedback operational amplifiers (CFOA), three resistors and two capacitors which not only realizes an universal biquadratic filter (capable of realizing all the five basic filter functions), but can also realize two different single resistance controlled oscillators (SRCO) and a lossless synthetic inductor. The workability and the multifunction capability of the proposed circuit configuration has been demonstrated from SPICE simulations based upon a CMOS CFOA architecture implementable in 0.18 mu m CMOS technology, as well as through hardware experimental results using commercially available AD844-type integrated circuit CFOAs. The total harmonic distortion (THD) of the various filters has been found to be below 1.34 % and the power dissipation approximately 2.96 mW while for the SRCO-mode, the % THD has been found to be 1.99 % at one output and 1.61 % at the other output, with total power dissipation being 2.96 mW. In addition, temperature analysis, noise analysis and Monte Carlo analysis have also been performed.

In this communication, an improved multifunction network configuration realizable with only two Current Feedback Operational Amplifiers (CFOAs) has been introduced which can realise (i) a universal filter (ii) two different grounded capacitor single resistance controlled oscillators (GC-SRCOs) and (iii) two positive and two negative synthetic grounded inductors, by altering certain network connections with a variety of useful characteristics and features, as compared to a similar circuit presented earlier. The workability of the various modes of operation of the proposed circuit configuration has been verified through SPICE simulations as well as hardware implementations based on commercial-off-the-shelf (COTS) AD844-type CFOAs.

Summary A new synthetic floating simulator topology is proposed which realizes lossy parallel inductance (R‐L), lossy parallel capacitance (R‐C), lossy parallel C‐D, and lossless floating capacitance multiplier (FCM) circuits using only three current feedback operational amplifiers (CFOA) as active elements and three impedances. In all the presented circuits, the value of L, C, and D is independently controllable through a single resistance without requiring any matching condition for passive elements. A novel feature of the proposed circuit involves a straightforward adjustment in the CFOA connections, allowing the circuit to function as either a floating lossless immittance simulator or a floating series‐type lossy immittance simulator. Various application examples of the presented circuits such as lead compensator, lag compensator, first‐order high‐pass filter, and fourth‐order Butterworth filter are also given to justify the theoretical analysis. To validate the workability of the proposed circuits, several analyses are conducted, including frequency analysis, transient analysis, Monte‐Carlo analysis, and temperature analysis, using the macro‐model of AD844 in the SPICE simulation tool. Experimental results of the parallel R‐L simulator and application examples are also provided using commercially available IC AD844‐type integrated CFOAs.

A new first-order universal filter structure is presented in this article using a single differential difference current conveyor (DDCC). The proposed circuit can provide three first-order filter functions namely, high-pass filter (HPF), low-pass filter (LPF), and all-pass filter (APF) in voltage mode (VM) and transadmittance mode (TAM) both. A voltage amplifier with a gain of 2 is required for the realization of the APF functions in both the modes while for LPF and HPF, no condition is required. The pole frequency and gain of the proposed circuit can be controlled separately. The effect of the parasitic impedances of the DDCC has been modeled in the nonideal equivalent circuit from which nonideal parameters have been evaluated and compared with their ideal ones. Application examples of the proposed circuits configured as amplitude equalizer (in both modes) and in the realization of a simple wideband band-pass filter are also discussed. The functionality of the proposed circuit as well as its mentioned application circuits is verified using complementry metal oxide semiconductor DDCC to support the theoretical propositions. Some experimentally observed frequency responses and transient responses of the various VM filters have also been corroborated using DDCC implemented using AD844 ICs.

Summary In this communication, two new positive lossy series inductor simulator circuits using single current differencing buffered amplifier (CDBA), one capacitor, and three resistors are presented. In both the proposed circuits, the inductance value is independently controllable through a grounded resistor, which may be implemented using a voltage‐controlled resistor (VCR), facilitating electronic tuning. Moreover, one of the circuits presented utilizes the intrinsic resistance (internal resistance available at input ports p and n) of the CDBA, thereby enabling electronic control and establishing the inductor simulator as canonical. Both the circuits are analyzed for non‐ideal behavior by taking into account the parasitic elements of CDBA and compared with their ideal counterparts. To demonstrate the efficacy of the proposed series RL simulator circuits, SPICE simulations are performed using CMOS CDBA, and the performance of the proposed circuits is evaluated by designing a lead compensator. The simulation and experimental results of the proposed circuits, along with the application examples employing CDBA realized with the off‐the‐shelf available IC AD844, have also been corroborated.

In this paper, a new lossy capacitance multiplier (CM) circuit using a single current follower differential input transconductance amplifier (CFDITA), one resistor and one capacitor (virtually grounded) is presented. The proposed circuit does not require any passive component matching constraints and has independently controllable equivalent capacitance with a multiplication factor up to 7102. Both ideal and non-ideal analyses of the proposed CM circuit are carried out and compared. The performance of the proposed CM circuit is validated using a CMOS CFDITA and its validity is supported by various analyses including frequency analysis, transient analysis, Monte-Carlo analysis and temperature analysis. The workability of the proposed circuit is also tested using layout design, and its pre and post-simulated results are appended. The results are further confirmed with experimental results using the AD844 and LM13700 ICs with CFDITA implementation.

In this communication, a novel inverse filter configuration is introduced, demonstrating the capability to realize inverse filter responses, namely, inverse low pass filter (ILPF), inverse high pass filter (IHPF), inverse band pass filter (IBPF), and inverse band reject filter (IBRF), utilizing only one Operational Transresistance Amplifier (OTRA) along with a minimal number of passive elements. The proposed inverse filters are meticulously validated through simulations in Cadence PSpice, implemented in CMOS TSMC 0.18μ m technology. The simulated characteristics closely align with the theoretical results. Additionally, a comprehensive analysis encompassing non-ideal aspects, noise considerations, Monte Carlo simulations, and sensitivity analysis has been conducted.

This paper presents a new circuit approach to realize a capacitance multiplier circuit with positive and negative multiplication factors. Based on this approach, two new implementations of positive and negative grounded capacitance multiplier (GCM) circuits are proposed, which utilize only one current follower differential input transconductance amplifier (CFDITA), in conjunction with only one resistor and one virtually grounded capacitor. The presented GCM circuits can enhance a low capacitance value to a very high value (used in low frequency applications), up to 9202 times its original value. An important aspect of the proposed circuits involves designing a lossy parallel inductor circuit by interchanging the passive elements (RC:CR transformation) with each other. The obtained value of the capacitance and inductance can be controlled independently and electronically through the transconductance of CFDITA. The practical usability of the suggested circuits as first and second order filters is discussed. The functionality of the proposed GCM circuits is validated using CMOS CFDITA implemented with 180 nm TSMC technology parameters. Experimental verification of the proposed circuits and application examples is reinforced through the utilization of CFDITA implemented with readily available ICs AD844 and LM13700. These outcomes emphasize the dependability of the suggested circuits.

A new universal active filter configuration is presented in this paper which is capable of realizing all three first-order filter responses namely all pass (AP), low pass (LP) and high pass (HP) using a single second generation voltage conveyor (VCII+), a virtually grounded capacitor and two resistors. The proposed circuit offers tunability of the cut-off frequency, gain (for HP filter) and simultaneous availability of two filter outputs, one at a low impedance node (HP/AP), the other output, namely the LPF will require a voltage buffer to avoid loading. The nonideal analysis of filter responses based on the nonideal model of VCII+ is carried out by considering all the parasitic immittances and nonideal gains and found that they have no significant effect on the performance of the proposed filter structure. Sensitivity analysis with respect to active and passive components has also been carried out. The functionality of the presented circuit has been validated through simulations and experimental results, where the VCII+ was implemented using the macro model of the commercially available CFOA IC AD844. Additionally, the proposed circuit has been tested using a CMOS VCII+ implemented with 0.18[Formula: see text][Formula: see text]m TSMC technology parameters. The tests include advanced evaluations based on Monte Carlo simulations.

A new explicit-current-output (ECO) single-resistance-controlled-oscillator (SRCO) using a single CFOA has been presented which (i) provides independent control of the condition of oscillation and the frequency of oscillation (both through two separate resistors) (ii) employs all grounded capacitors (as preferred for IC implementation) (iii) is suitable for generating very-low-frequency oscillations and (iv) enjoys control of oscillation frequency through a ground resistor (thereby offering suitability for VCO realisation by replacing the resistor by JFET/MOSFET-based voltage-controlled-resistance). The proposed circuit represents a significant development due to the reason that although ECO SRCOs have been reported earlier using two or more CFOAs, to the best of the authors’ knowledge, any circuit using only a single CFOA along with the simultaneous attainment of the above mentioned properties, has not been reported in the literature earlier till date. The workability of the proposed circuit has been verified by experimental results using AD844-type CFOA and some sample results have been included.

In this paper, four new generalized configurations of grounded parallel-type immittance simulators are proposed. These circuits implement parallel resistor-inductor (RL), parallel resistor-capacitor (RC), parallel capacitor-frequency-dependent negative resistance (CD), and capacitance multiplier configurations utilizing only two second-generation voltage conveyors (VCII +/-) as active elements along with three impedances, without the need for specific matching conditions. The applicability of the proposed parallel RL and capacitance multiplier configurations as a second-order high-pass filter (HPF) and a first-order low-pass filter (LPF), respectively, is also demonstrated. These applications illustrate the versatility and utility of the proposed structures. Frequency, transient, and Monte Carlo analysis utilizing the CMOS VCII +/- in the SPICE simulation tool have also been performed to validate the feasibility of the presented circuits. Further validation is carried out through layout design in Cadence Virtuoso, employing 0.18-mu m CMOS technology. Both presimulation and postsimulation results are presented for a thorough assessment of the proposed circuits. Also, the claimed theory is verified by experimental results based on the VCII implementation with commercially available IC AD844. Four new grounded parallel-type immittance simulators using two second-generation voltage conveyors (VCII +/-) and three impedances, implementing parallel RL, parallel RC, parallel CD, and capacitance multiplier configurations without specific matching conditions. The proposed circuits are validated through frequency, transient, and Monte Carlo analysis in SPICE and layout design in Cadence Virtuoso (0.18-mu m CMOS technology). Practical applications as second-order high-pass and first-order low-pass filters demonstrate the versatility of the circuits. Experimental results using commercially available IC AD844 confirm the theoretical findings.image

This communication presents two new voltage mode (VM) third-order quadrature sinusoidal oscillator (TOQSO) configurations employing three operational transresistance amplifiers (OTRAs), six resistors and three virtually grounded capacitors. The proposed circuits have independent control of condition of oscillation (CO) and frequency of oscillation (FO) utilizing the intrinsic current differencing property of the OTRA. The proposed TOQSOs have ideally zero output impedance, a feature suitable for easy cascadability. Nonideal and sensitivity analyses have been carried out and compared with those obtained from ideal analysis. The presented TOQSOs have been simulated using OTRAs implemented with macro model of off-the-shelf available AD844 ICs. Experimental results have also been included using OTRAs realized with commercially available AD844 CFOA ICs.

An exhaustive literature survey on current feedback op-amps (CFOA)-based oscillators circuits indicates that till date, no canonic single-CFOA-based single resistance controlled oscillators (SRCO) employing two grounded capacitors (GC) has ever been discovered so far. The main object of this communication is to present eight new single resistance tunable oscillators (SRTO) each of which uses only one CFOA, six resistors and two grounded capacitors. The workability of the presented SRTOs has been demonstrated by the experimental results using commercially available AD844-type integrated circuit CFOA.

Two new configurations for the realization of lossy grounded inductor each employing one current differencing buffered amplifier (CDBA), three resistors, a voltage follower and one grounded capacitor are presented. The realized inductances from the proposed configurations have independent tunability through a single resistor. The proposed circuits make use of the intrinsic current differencing property of CDBAs by not leaving any of its input terminals open or connected to ground. Both the presented circuits use grounded capacitor (which is particularly attractive for integrated circuit implementation) connected at the Z-terminal of CDBA which may also absorb the parasitic capacitance. The proposed lossy inductors can be used in applications such as low frequency sinusoidal oscillator, low pass filter (LPF) and band pass filter (BPF). Such examples may be suitable from the viewpoint of biomedical instrumentation and geo-physical applications. Non-ideal analysis has been carried out to support the theoretical propositions for both the proposed circuits. PSPICE simulation results with CMOS CDBA have been presented to establish the workability of the proposed lossy inductor structures. Experimental results using commercially available AD844 ICs have also been included to demonstrate the viability of the proposed lossy inductors based on CDBAs.

In this communication, three new negative-grounded capacitance multiplier (NGCM) circuits employing a single current feedback operational amplifier (CFOA), two resistors, and a grounded capacitor (which is most suitable for parasitic absorption and also IC implementation point of view) are investigated. No matching constraints are required for any of the proposed circuit realizations. Out of the three proposed circuits, multiplication factor of one of the capacitance multiplier can be controlled electronically as the controlling resistor is grounded, which can easily be replaced by a voltage-controlled resistor (VCR). Error analysis of the proposed NGCMs has been carried out, and the results have been compared with those obtained from ideal analysis. To substantiate the feasibility of the proposed circuits, macro model of CFOA has been used, and the simulations have been performed in Personal Simulation Program with Integrated Circuit Emphasis (PSPICE). Simulation results for frequency analysis, Monte-Carlo analysis, and temperature analysis have been included for the theoretical justification. Noise analysis and power supply rejection ratio analysis have also been carried out for the proposed circuits. The multiplication factors of the proposed NGCMs have been obtained up to a maximum value of 2001. The impedance and phase of the proposed NGCM structures are insensitive with temperature. The functionality of the proposed structures has also been validated experimentally using commercially available IC AD844-type CFOA.

This paper presents a novel grounded negative series RL and RC simulator circuit. The presented circuit uses one current feedback operational amplifier (CFOA) and three passive elements without requiring any matching condition. The proposed circuit can also be configured as negative capacitance in series with frequency dependent positive resistor (FDPR) and negative capacitance divider with proper selection of passive elements. Various analyses, including frequency, transient, and temperature analysis have been performed to support the theoretical findings using macro-model of CFOA AD844 with PSPICE. To check the workability of the proposed negative series RL and negative series RC circuits, inductance cancellation circuit and capacitance cancellation circuit are given as application examples.

In the past, several new active elements have been employed to realize single-resistance-controlled oscillators (SRCO) of which the four-terminal-floating-nullors (FTFN) have attracted considerable attention in the literature. In this paper, an ingenious methodology of deriving single-FTFN-based canonic grounded-capacitor (GC) SRCOs has been presented. It is shown that such oscillators can be systematically evolved from a class of earlier known op-amp-based SRCOs through the application of two theorems pertaining to RC-nullor oscillators published earlier. The presented methodology not only yields all the previously known (four) single-FTFN-based canonic GC SRCOs but also reveals a number of (12) new circuits, which have not been known in the open literature earlier. The viability of the evolved oscillator circuits has been confirmed through SPICE simulations, and some simulation results have been given.

Recently, three current feedback operational amplifiers (CFOA)-based third-order quadrature sinusoidal oscillators (TOQSO) have been presented whose condition of oscillation (CO) and frequency of oscillation (FO) can be regulated independently. In this communication, we present two new TOQSO circuits, which require only two CFOAs and yet achieve as significant features as the quoted circuits, namely, the availability of fully uncoupled control of CO and FO, availability of both outputs from ideally zero output impedance nodes (which is beneficial for easy cascadability in VM operations) and employment of all (three) grounded capacitors as preferred for IC implementation. The verification of the workability of proposed circuits has been carried out experimentally using commercially available off-the-shelf ICs AD844-type CFOAs, and some experimental results have been appended.