Frequency-dependent Negative Resistance Research Articles

Two inverting CFOA-Based lossless floating immittance simulator

Inverting current feedback operational amplifier (ICFOA)-based lossless floating immittance simulator (FIS) is introduced in this manuscript. In the proposed FIS, floating capacitance multiplier (FCM), simulated floating inductor (SFI), and floating frequency-dependent negative resistor (FFDNR) can be obtained with selections of the passive elements. The proposed FIS is realized with a minimum number of passive elements. The proposed FIS is not suffered from any resistor and/or capacitor matching conditions; nevertheless, all the passive elements are chosen as floating. All the simulations of the FCM, SFI, and FFDNR are made by using the SPICE program in which 0.18 µm CMOS technology parameters are utilized. As an application example, the second-order passive band-pass filter is given for the FCM and SFI. Simulation results confirm the ideal results between about 5 Hz and 2 MHz for the FCM, between approximately 200 Hz and 5 MHz for the SFI, and between about 50 kHz and 13 MHz for the FFDNR. The proposed circuit has 1.49 mW power dissipation. In addition, the experiments of the proposed circuit and application are achieved by using AD844s instead of the ICFOAs.

Linear Voltage Controlled Oscillator Implementation in Electronically Variable Immittances

New realization schemes of electronically tunable inductor (L) and Frequency-Dependent Negative Resistance (D) type immittances using a Current Feedback Amplifier (CFA) and Multiplication Mode Current Conveyor (MMCC) composite active building block (ABB) are proposed. Applications of the immittances to the design of selective filters and LC-type linear voltage controlled quadrature oscillator (LVCQO) are presented. Experimental results based on PSPICE simulation and hardware design for a linear range of oscillation frequency (fo ~ 13.6MHz) with satisfactory phase-noise figure on the oscillator wave response had been verified. Effects of the Active Building Block (ABB)-nodal imperfections are analyzed to be insignificant. The new ideas in this article are two types of immittance functions realizable in the same topology; appropriate frequency-domain selective responses are also presented with experimentation results.

Novel FDNR, FDNC and lossy inductor simulators employing second generation voltage conveyor (VCII)

AbstractIn this research the second‐generation voltage conveyor (VCII) is employed in the design of grounded frequency dependent negative resistor (FDNR) and Frequency dependent negative conductance (FDNC). Additionally, two lossy parallel and series R‐L inductor simulators are also designed. To the best knowledge of the authors above mentioned immittance simulators are first time implemented using VCII. The FDNR requires two VCII, two capacitors and one grounded resistor. FDNC is implemented using three VCII, three resistors and two grounded capacitors. The R‐L inductor emulators requires two VCII, two resistors and one grounded capacitor. All the presented immittance simulators do not require any kind of passive component matching. The non‐ideal gain and sensitivity analysis is conducted to study their performance under circuit parameter variations. Parasitic analysis is also done for the FDNR, FDNC and R‐L inductance simulators to study the effect of parasitic impedance on the circuit operation. To validate the designs, they are simulated in Cadence design environment using 0.18 μm process design kit (PDK) at ±0.9 V supply. Additionally, the circuits are also validated using the macro model of commercially available integrated circuit (IC) AD844. The theoretical and simulation results are found to be in close agreement.

Configuration for a grounded lossy impedance simulator employing CC-CFAs and grounded passive elements

This article presents a configuration that can simulate both a resistor in series with a frequency-dependent negative-resistance (R-D) and a resistor in series with a capacitor (R-C), with a different selection of passive elements. The proposed circuit employs only two current-controlled-current-feedback- amplifiers (CC-CFAs) and grounded passive elements. This configuration does not require passive element matching, and the simulated equivalent element values can be tuned electronically by applying a biasing current to the CC-CFAs. To demonstrate the application of the proposed grounded series R-D impedance simulator, it is applied to a second-order notch filter and a fifth-order elliptic lowpass filter, whereas the series R-C impedance simulator is applied to a secondorder resonance circuit to find the band-pass response of the input current. Our theoretical analysis is confirmed by the results of a PSPICE simulation.

CFOA-based floating frequency dependent negative resistor, floating capacitance multiplier, and simulated floating inductor

This paper introduces a new floating simulator circuit suitable for realizing a floating frequency dependent negative resistor (FFDNR) or a floating capacitance multiplier (FCM) with selections of the passive elements. In addition, a new circuit for realizing a simulated floating inductor (SFI) is introduced. The introduced FFDNR, FCM, and SFI use three current feedback operational amplifiers. The introduced FFDNR and FCM include a canonical number of passive components without any matching requirements, while the SFI contains three resistors and a grounded capacitor with a single resistive matching condition. Voltage-mode band-pass, low-pass, and notch filters are given as application examples.

CCII-Based Lossless Floating Frequency-Dependent Negative Resistor with Minimum Passive Elements

This paper proposes a new lossless floating frequency-dependent negative resistor (FDNR). The proposed floating FDNR circuit is designed with two dual output second-generation current conveyors (DO-CCIIs) and a minimum number of passive elements. The first DO-CCII behaves like a minus-type second-generation current conveyor, while the other is modified DO-CCII. The proposed floating FDNR does not require any passive element matching conditions, but all the passive elements are floating. The simulations are made through the SPICE program. A second-order high-pass filter (HPF) is given as an application example. In addition, some experimental results are included for the second-order HPF in which AD844s are utilized.

New Voltage-Variable Immittance Functions: Linear Voltage-Controlled Quadrature Oscillator

A new voltage-variable immittance functions (VVIFs) implementation has been proposed. Here two types of grounded-immittances function have been realized viz., inductor (L) and Frequency-Dependent Negative Resistor (D) using a pair of ABBs i.e. Current Feedback Amplifier (CFA-AD844) amalgamated with analog voltage-multiplier (AD-835) devices. Thereafter, high-quality (Q) resonant filters and voltage-controlled quadrature oscillator (VCQO) implementation with linear tuning law are designed using the proposed VVIF. The analysis indicates that the filter/oscillator parameters are impervious to the effects of the CFA-device parasitic capacitors. A VCQO-linear tuning range of f o∼14 MHz with a satisfactory phase-noise margin of (–)103 dBc/Hz at 29 KHz for the LC-type linear QO has been experimentally observed.

New single VDCC Based Electronically Adjustable FDNR using Grounded Capacitances

A FDNR (Frequency Dependent Negative Resistance) simulator has been presented, which uses single Voltage Differencing Current Conveyor (VDCC) along with two grounded capacitances to realize the pure FDNR function. The proposed FDNR simulator places itself as one of the most compact circuit architecture present in the available literature. It is a resistor-less realization and finds no requirement of any active/passive component/parameter matching to realize the FDNR behaviour. The presented analysis shows that the proposed circuit remains always stable under the effect of parasitics irrespective of any values of circuit parameters, which is not witnessed in many previously reported FDNRs. The usability of realized synthetic FDNR has been checked through validation of developed higher-order CDR filters by using the proposed FDNR. To verify the designed circuits, the presented configurations have been simulated under the PSPICE simulation environment. The experimental results are shown for the commercial ICs (AD844 and CA3080) based physical realization of described FDNR.

A unity‐gain approach to a simple FDNR‐based chaotic jerk oscillator

A unity-gain approach is proposed for a simple chaotic jerk oscillator based on frequency-dependent negative resistance. Both unity-gain and frequency-dependent negative resistance techniques are demonstrated together, for the first time, for a simple chaotic jerk circuit. The oscillator is attractive due to the use of a grounded diode and circuit simplicity of only seven electronic components, only one of which is an active device. The simplicity results in fewer components of both active and passive devices compared to existing frequency-dependent negative resistance-based chaotic circuits. The maximised value of the largest Lyapunov exponent is relatively high at 14.62.

New resistor-less tunable floating and grounded FDNR simulators

ABSTRACT This article proposes new electronically tunable simulation configurations of synthetic grounded and floating frequency-dependent negative resistances (FDNRs) without using any resistances. The presented simulators have been realised by using two voltage differencing transconductance amplifiers (VDTAs) along with two capacitances. As per the knowledge of the authors, the depicted VDTA-based simulator circuits are the most compact configurations as compared to any other VDTA-based pure FDNR simulator reported so far. The circuits possess the feature of electronic tunability which means that the realised FDNR value can be controlled by using bias currents of employed VDTAs. Moreover, the reported structures simulate ideal FDNR behaviour without any requirement of fulfiling the parameter-related conditions. An analysis has been presented and discussed to find the behaviour of the presented circuits under non-ideal effects. The operation of the simulated FDNRs has been checked by constructing higher-order CDR filters. The working of the designed circuits has been shown through the simulation results generated using PSPICE with 0.18 um CMOS technology. Finally, the experimental results using commercial IC have been discussed.

Inductanceless high order low frequency filters for medical applications

<p>In this paper, a designed circuit used for low-frequency filters is implemented and realized the filter is based on frequency-dependent negative resistance (FDNR) as an inductor simulator to substitute the traditional inductance, which is heavy and high cost due to the coil material manufacturing and size area. The simulator is based on an active operation amplifier or operation transconductance amplifier (OTA) that is easy to build in an integrated circuit with a minimum number of components. The third and higher-order Butterworth filter is simulated at low frequency for low pass filter to use in medical instruments and low-frequency applications. The designed circuit is compared with the traditional proportional integral controller enhanced (PIE) and T section ordinary filter. The results with magnitude and phase response were compared and an acceptable result is obtained. The filter can be used for general applications such as medical and other low-frequency filters needed.</p>

Q-Factor of the Resonators With Frequency Dependent Negative Resistor

<i>Q</i>-Factor of the Resonators With Frequency Dependent Negative Resistor

Realization of Seventh-Order Chebyshev Active Low-Pass Filter

Background: CCCII implementation of the classic seventh-order Chebyshev filter is relatively rare. This work is a supplement to it. Methods: By a floating negative simulating resistance using single the second generation current-controlled conveyor (CCCII), we design a new current buffer to employ one CCCII and one multiple output CCCII (MOCCCII), and a new grounded MOCCCII-employed the frequency-dependent negative resistance (FDNR). Moreover, by employing a classic seventh-order Chebyshev passive filter as a prototype and utilizing adjoint network theory, a seventh-order Chebyshev active low-pass filter is realized through applying the Bruton transform, frequency and impedance scaling technique, FDNR, and component replacement method. The filter employs only grounded capacitors and nine CCCIIs, and its the performance can be controlled through adjusting bias currents of the CCCIIs. Results: The designed circuit is simulated with Multisim, which shows that the filter is correct and effective. Conclusion: A seventh-order Chebyshev active low-pass filter with Amax=0.5 dB and fc=10 kHz, is realized.

Voltage-Tunable Immittance Functions: Linear Voltage-Controlled Quadrature Oscillator Implementation

ABSTRACT A new scheme on the realization of voltage-tunable immittance function (VTIF) is proposed. Two types of grounded- of high-quality (Q) resonant filters and voltage-controlled quadrature oscillator (VCQO) with linear tuning law are presented. Analysis indicates that the filter /QO parameters are impervious to the ABB-parasitic components. Experimental results exhibit a VCQO-linear tuning range of fo ~14MHz with a satisfactory phase-noise margin of immittances viz., inductance (L) and Frequency-Dependent Negative Resistance (D) are derived using the Current Feedback Amplifier (CFA) combined with analog voltage-multiplier elements as the active building block (ABB). Subsequently implementation of LC-bandpass and rD-band-reject selective filters, along with QO designs are presented with low THD and phase noise of (─)104 dBc/Hz at 30 KHz offset. Experimental results of the proposed circuits had been satisfactorily verified using standard commercially available IC-modules.

Electronic Tuneable Grounded and Floating FDNR using FTFNTA

ABSTRACT In this manuscript, an electronically tunable resistor-less grounded and floating FDNR (Frequency-Dependent Negative Resistance) is presented. The proposed circuit uses two FTFNTAs (Four Terminal Floating Nullor Transconductance Amplifier) and three capacitors for the design of floating FDNR; while only one FTFNTA and two capacitors are used for the design of grounded FDNR. The electronic tunability is achieved by altering the bias current of the FTFNTA. The workability of the proposed FDNR is demonstrated through the implementation of 4th order Butterworth band pass filter (BPF) and 2nd order low pass filter (LPF). The PSPICE simulation results are included to verify the theoretical interpretation.

New floating/grounded FDNC and non-ideal grounded FDNR simulators based on VDTA

The paper proposes a new grounded/floating frequency dependent negative conductance (FDNC) simulator, and a non-ideal frequency dependent negative resistance (FDNR) simulator, based on deployment of voltage differencing transconductance amplifiers (VDTA), along with two grounded capacitances. The presented simulators feature electronic controllability of realized negative conductance/resistance via DC bias current of VDTA, with no component matching constraints. The non-ideality analysis of the circuits is also presented. The proposed solutions exhibit an excellent behaviour under non-ideal conditions with low active/passive sensitivity. The working of the presented simulators has been verified by corresponding voltage mode filter design examples, and has been verified by HSPICE simulations which were carried out on the basis of 0.18 μm CMOS technology.

Floating general immittance function simulator

A floating general immittance function simulator circuit is presented using two differential voltage to current converters (DVTCs) and three passive components. The developed DVTC to be used in this work is realized with the flipped voltage follower, achieving low-voltage operation. By selecting proper passive components, the proposed floating simulator circuit can realize synthetic inductor, capacitor, resistor and frequency-dependent negative resistance (FDNR) without changing its configuration. No component matching conditions and cancellation constraints are necessary. Furthermore, non-ideal transfer gain effects on the proposed simulator circuit are discussed. As applications for the proposed floating simulator, a second-order RLC bandpass filter and a fourth-order resistively terminated LC bandpass filter are shown. To verify the theory, the proposed simulator and its applications are simulated using 0.25-μm CMOS process technology.

CMOS Analog Filter Design for Very High Frequency Applications

A design strategy for the synthesis of high-selectivity/low-order analog filters in Complementary Metal-Oxide-Semiconductor (CMOS) technology for very high frequency (VHF) applications is presented. The methodology for the reconstitution of a given transfer function by means of Signal Flow Graphs (SFG) manipulation in canonical form is proposed leading to a fully differential g m -C biquad filter. As a practical example, the design of a notch filter intended to suppress interferers in the lower sideband (400 MHz) of the Medical Implant Communication Service (MICS), in single-poly, 6-metal layers; Mixed-Signal/RF 0.18 µm CMOS technology is realized. To compare the performance of the proposal with some other solution, the design of a 7th order elliptic notch filter based on Frequency Dependent Negative Resistors (FDNRs) was also accomplished. The attained simulation results prove that the proposal is competitive compared to the FDNR solution and some other state-of-the-art filters reported in the literature. The most salient features of the proposed notch biquad include: the selectivity, whose value is comparable to that of a 7th order elliptic approach and some other 3rd order filters; a high-frequency operation without resonators; linearity, with a +15 dBm I I P 3 ; a reduced form factor with a total occupied area of 0.004282 mm2 and mostly a low design complexity.

Multiplierless chaotic Pseudo random number generators

This paper presents a multiplierless based FPGA implementation for six different chaotic Pseudo Random Number Generators (PRNGs) that are based on: Chua, modified Lorenz, modified Rössler, Frequency Dependent Negative Resistor (FDNR) oscillator, and other two systems that are modelled using the simple jerk equation. These chosen systems can be employed in high speed applications because they don’t utilize any hardware multiplier. The proposed PRNGs have been implemented using VHDL, synthesized on Xilinx, using the FPGA: XC5VLX50T, and tested using the NIST statistical suite. Furthermore, a comparison has been established between the performance of all the PRNGs, regarding the implementation area, speed, and the statistical randomness quality. It has been found that the modified Lorenz PRNG has the best randomness quality and the best hardware performance as it can pass all the NIST tests while operating at 298.597 MHz and utilizing only 0.23% and 0.62% from the FPGA’s slice registers and Look-Up-Tables (LUTs) respectively.

Generalized Fully Adjustable Structure for Emulating Fractional-Order Capacitors and Inductors of Orders less than Two

A novel scheme suitable for the emulation of fractional-order capacitors and inductors of any order less than 2 is presented in this work. Classically, fractional-order impedances are characterized in the frequency domain by a fractional-order Laplacian of the form $$s^{\pm \alpha }$$ with an order $$0<\alpha <1$$. The ideal inductor and capacitor correspond, respectively, to setting $$\alpha =\pm 1$$. In the range $$1<\alpha <2$$, fractional-order impedances can still be obtained before turning into a Frequency- Dependent Negative Resistor (FDNR) at $$\alpha =\pm 2$$. Here, we propose an electronically tunable fractional-order impedance emulator with adjustable order in the full range $$0<\alpha <2$$. The values of the emulated capacitance/inductance, as well as the bandwidth of operation, are also electronically adjustable. The post- layout simulation results confirm the correct operation of the proposed circuits.