Oscillator Circuit Research Articles

Operation of colpitts oscillator based on wide band gap operational amplifiers

ABSTRACT The present work is concerned with studying and analysing the operation of the Colpitts oscillator based on operational amplifier with different technologies. During the study, two different operational amplifier types, TLV2374IEN and TL084ACN were used. First, the different operational amplifier parameters including; input offset voltage, input bias current, offset current, voltage gain, input impedance, and output impedance, as well slew rate were measured. Second, the effect of oscillator circuit inductance values (L) on the circuit parameters including; quality factor, signal frequency, inductor impedance, oscillator output impedance, amplification factor and output voltage gain were investigated, whenever the two proposed operational amplifiers were used. The quality factor, signal frequency, inductor impedance, and oscillator output impedance were observed to be affected by L variation. While, both the attenuation and amplification factors were shown to be affected by L till the value of around 860 µH, after this value a semi-saturation for the parameter values wasobserved.

Preparation and characterization of high stability silicone-based colloidal magnetic fluids

The Fe3O4 magnetic nanoparticles were prepared using a chemical co-precipitation and were coated with surface-active agents including silane coupling agents KH550 and KH792, carboxyl-functionalized silicone oil, and amine-functionalized silicone oil. In this study, the four types of magnetic nanoparticles coated with different surface-active agents were characterized using XRD, FTIR, TEM, VSM, etc. to determine the effects of different surface-active agents on the magnetic nanoparticles. Furthermore, four different types of silicone oil-based colloidal magnetic fluids were prepared, and their stability was analyzed using an LC oscillation circuit. The results show that the magnetic nanoparticles coated with carboxyl-functionalized silicone oil have an average particle size of about 12.4 nm and a saturation magnetization of 65.2 emu/g. They exhibit the strongest dispersion stability in the base fluid, and the prepared silicone oil-based colloidal magnetic fluids can remain stable under a magnetic field for up to 2 months without sedimentation. Moreover, they exhibit excellent viscosity-temperature performance, which enhances the practical application value of silicone oil-based colloidal magnetic fluids.

Influence of Microinjection of Kynurenic acid into the Pre-Botzinger Complex on Swallowing in the Cat

Recent evidence supports the involvement of the pre-BÖtzinger complex (pre-BOT) in spatiotemporal features of swallowing and swallowing-breathing coordination in mice. We hypothesized that pharmacological disruption of glutamate neurotransmission in this brainstem region would perturb the swallow motor pattern in anesthetized cats. Electromyograms (EMGs) of upper airway muscles were recorded in anesthetized, spontaneously breathing cats (n=5). Swallowing was induced by injection of 3 cc of water into the oropharynx. Multi-barrel micropipettes were employed to inject artificial cerebrospinal fluid or kynurenic acid (KYN; 50 mM, 44±3 nL per injection) bilaterally into the region of the pre-BOT. Microinjection sites were confirmed histologically by detection of fluorescent beads that were suspended in the microinjectate. Blocking glutamate-related neuronal excitation by bilateral microinjections of the nonspecific glutamate receptor antagonist kynurenic acid had no effect on the number of swallows induced by water injection (control 2.3±0.3; KYN 3.0±0.7; P<0.32). Swallow durations were significantly increased following microinjections of KYN from 691±54 ms to 812±81 ms (p<0.04). KYN significantly reduced the magnitudes of geniohyoid (control 97±3 % of median; Kyn 47±12% of control median, p<0.02), thyrohyoid (control 100±3% of median; KYN 69±8% of control median, p<0.01), and posterior cricoarytenoid (control 103±2% of median; KYN 74±8% of control median, p<0.04) muscle EMGs during swallowing. There was no significant effect of microinjection of KYN on the magnitudes of thyroartytenoid, mylohyoid, or thyropharyngeus electromyograms during swallowing. The results suggest that disruption of glutamate neurotransmission in the preBOT has preferential effects consistent with actions on motor drive to hypoglossal and ventrolateral motoneuron pools that participate in swallowing. Lengthening of swallow duration induced by KYN supports a role for the preBOT in modulating the excitability of the swallow oscillatory circuit. NIH HL163008; NIH HL 131716; HL 155721. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Selenium catalysis enables negative feedback organic oscillators.

The construction of materials regulated by chemical reaction networks requires regulatory motifs that can be stacked together into systems with desired properties. Multiple autocatalytic reactions producing thiols are known. However, negative feedback loop motifs are unavailable for thiol chemistry. Here, we develop a negative feedback loop based on the selenocarbonates. In this system, thiols induce the release of aromatic selenols that catalyze the oxidation of thiols by organic peroxides. This negative feedback loop has two important features. First, catalytic oxidation of thiols follows Michaelis-Menten-like kinetics, thus increasing nonlinearity for the negative feedback. Second, the strength of the negative feedback can be tuned by varying substituents in selenocarbonates. When combined with the autocatalytic production of thiols in a flow reactor, this negative feedback loop induces sustained oscillations. The availability of this negative feedback motif enables the future construction of oscillatory, homeostatic, adaptive, and other regulatory circuits in life-inspired systems and materials.

A Novel Induction-Type Pressure Sensor based on Magneto-Stress Impedance and Magnetoelastic Coupling Effect for Monitoring Hand Rehabilitation.

Visualization of training effectiveness is critical to patients' confidence and eventual rehabilitation. Here, an innovative magnetoinductive pressure sensor is proposed for monitoring hand rehabilitation in stroke hemiplegic patients. It couples the giant magneto and stress-impedance effects of a square spiral amorphous wire with the giant magnetoelastic effect of a polymer magnet (NdFeB@PDMS). The addition of the magnetoelastic layer results in a sensitivity improvement of 178%, a wide sensing range (up to 1 MPa), fast response/recovery times (40 ms), and excellent mechanical robustness (over 15 000 cycles). Further integration with an LC oscillation circuit enables frequency adjustment into the MHz range resulting in a sensitivity of 6.6% kPa-1 and outstanding linearity (R2 = 0.99717) over a stress range of up to 100 kPa. When attached to a commercial split-fingerboard, the sensor is capable of dynamically monitoring the force in each finger, providing a reading of the rehabilitation process. Unlike conventional inductive sensors, the sensor is based on an inductive force-responsive material (amorphous wire), which significantly boosts the sensitivity. The approach also demonstrates the potential of magnetoelasticity in static pressure sensing, which is highly sensitive to dynamic pressure only through electromagnetic induction. This makes it more suitable for long-term and continuous human health monitoring.

Superfluid oscillator circuit with a quantum current regulator

Superfluid oscillator circuit with a quantum current regulator

A New Criterion for Determining Optical Damage of Nonlinear Optical Crystals, Based on the Use of an RF Oscillator Circuit

A New Criterion for Determining Optical Damage of Nonlinear Optical Crystals, Based on the Use of an RF Oscillator Circuit

Designing a Fully Current-Controlled Memristors-Based Oscillator

One of the promising applications of locally-active memristors (LAMs) is to construct oscillators for oscillatory neural networks. By using two current-controlled (CC) LAMs, a fully CC LAM-based oscillator is designed in this paper. The oscillator principle originates from the small-signal inductive and capacitive impedance characteristics of two different CC LAMs, and thus extra reactance element is not required in the circuit. Based on bifurcation theory and small-signal analysis method, conditions of the equilibrium point instability are quantitatively derived. Theoretical analysis indicates that the circuit oscillation is dependent on three critical parameters. Then, according to the conditions of the equilibrium point instability, parameters design methods of the two LAMs are proposed, including the static and dynamic parameters. A simple NbOx CC LAM model is taken as an example to conduct detailed simulation analysis. The simulation results verify the feasibility of the proposed circuit and analysis methods. Finally, the effects of the LAM model parameters on the oscillator performance are investigated, which is helpful for optimal design of the oscillator.

Enhancing mathematical simulation: a novel integro spline quasi-interpolation for nonlocal dynamical systems

ABSTRACT In this research, we present a novel and computationally streamlined method to tackle nonlocal initial value problems through a combination of modeling and simulation. Our approach utilizes the Integro spline quasi-interpolation technique, renowned for its effectiveness in approximating nonlocal integrals. To validate the efficacy of our proposed method, we conduct comprehensive comparisons with alternative approaches found in the existing literature for integrating nonlocal functions. Additionally, we successfully apply our suggested approach to address nonlocal Riccati, resistor-inductor circuit, and Airy oscillator dynamical systems. The numerical results obtained from these applications convincingly demonstrate the advantages and effectiveness of our developed approach in enhancing mathematical simulation.

Energy and self-adaption in a memristive map neuron

Both capacitor and charge-controlled memristor (CCM) can regulate the inner energy levels during the release and accumulation of charges in these electronic components. Combination of inductive and capacitive components is crucial to build an oscillatory circuit, and incorporation of a nonlinear resistor is helpful to support nonlinear oscillation under continuous energy exchange between magnetic field and electric field. Relation between physical variables in neural circuits can be described by some equivalent nonlinear oscillators by applying scale transformation on the variables and parameters for the neural circuit, and the energy function becomes available from theoretical approach. In this work, a simple neural circuit coupled with a CCM is designed to obtain a memristive neuron model, and then linear transformation is applied to the sampled variables involved with time scale for time step, a new memristive map is obtained to discuss its energy characteristic and self-controllability under energy flow. The result provides guidance to measure the reliability of maps, and the new derived maps with reliable physical evidences can be further used in digital signal processing.

Observer‐based hybrid triggered control design for cluster synchronization of nonlinear complex dynamical networks

SummaryThe issues of cluster synchronization and state estimation for a class of nonlinear complex dynamical networks are concurrently focused in this study. In precise, led by the design of complex dynamical networks, a proportional integral‐based observer is implemented for achieving robustness, by the virtue of which the states of examined networks are estimated. Thereupon, a proportional integral observer‐based hybrid triggered control scheme is proposed, wherein, the switch‐over between time‐ and event‐ triggered scheme is governed through a Bernoulli distributed random variable. Further, with the application of mixed and passivity performance technique, the external disturbances for the addressed complex dynamical networks are reduced. Based on the Lyapunov stability theory, the requisite sufficient conditions in respect of linear matrix inequalities are provided which ensures the discussed complex dynamical network's synchronization phenomenon. In a further, the presented criteria are exploited for the attainment of required controller, proportional and integral gain matrices. In conclusion, the applicability of proposed results and efficacy of the undertaken strategy are evidently proven with the illustration of two numerical examples with Chua's circuit and Goodwin oscillator model.

Design of Wireless Multiple Gases Complementary Architecture Sensors Based on SnSe2 and PtSe2 Layered Films and Oscillating Circuits

AbstractOwing to the increasing demand for monitoring harmful toxic gases using small‐sized low‐power‐consumption gas sensors, a room‐temperature wireless complimentary gas sensor incorporating layered materials is proposed and demonstrated. The compact design allows the sensing module to be installed under all conditions and facilitates multiple detections of toxic gas. Highly chemical‐resistance‐sensitive materials based on n‐type SnSe2 and p‐type PtSe2 layered materials prepared by the plasma‐assisted chemical vapor reaction (PACVR) method at low temperatures are integrated with an oscillation circuit and antenna fabricated by a 28‐nm CMOS high‐k metal gate logic process to achieve dense, low‐powered, and wireless characteristics. By pairing n‐ and p‐type layered semiconductors, the gas sensors feature less influence from the surroundings, such as temperature and humidity, and enhance sensitivity to the target gas simultaneously. The wireless sensing detection method enables a sensor to make signal reception more convenient. Furthermore, a wireless gas sensor with self‐converging calibration using the advantage of a floating‐gate (FG) transistor to control the charge quantity by shifting the threshold voltage (Vth) of each transistor via the channel hot electron injection effect, which helps to reduce the impact of process variations, minimizing readout errors, is proposed.

Loop Conductance Adapting Methodology to Suppress Switching Oscillations in High-Frequency GaN-Based Circuits

Gallium nitride (GaN) devices have enormous potentials in electric vehicle (EV) applications. The trend of high frequency and high power density help increase EV mileage level greatly. However, due to the ultra-fast switching speed of the GaN devices and low damping level in the compact circuit, switching oscillations are prone to happen and sometimes even sustain, which affects the circuit stability heavily. In this research, loop conductance adapting methodology is proposed to solve this problem, which is inserting a loop conductance adapter (LCA) into the GaN-based circuit. The LCA can be in manifold forms and inserted into different positions. A modified negative conductance model is established, which is universal to all the forms and inserting positions. Based on the established model and a derived stability criterion, the optimized design method is proposed, with which the most appropriate LCA parameters could be calculated and the corresponding suppression effects could be predicted. The details of the design method are introduced with three typical LCA examples. All the theoretical achievements are verified with LTspice simulations and experiments. In addition, the three examples are compared with each other according to suppression effects and power losses. Suggestions about LCA inserting position selection are also proposed.

Abnormal gamma phase-amplitude coupling in the parahippocampal cortex is associated with network hyperexcitability in Alzheimer's disease.

While animal models of Alzheimer's disease (AD) have shown altered gamma oscillations (∼40 Hz) in local neural circuits, the low signal-to-noise ratio of gamma in the resting human brain precludes its quantification via conventional spectral estimates. Phase-amplitude coupling (PAC) indicating the dynamic integration between the gamma amplitude and the phase of low-frequency (4-12 Hz) oscillations is a useful alternative to capture local gamma activity. In addition, PAC is also an index of neuronal excitability as the phase of low-frequency oscillations that modulate gamma amplitude, effectively regulates the excitability of local neuronal firing. In this study, we sought to examine the local neuronal activity and excitability using gamma PAC, within brain regions vulnerable to early AD pathophysiology-entorhinal cortex and parahippocampus, in a clinical population of patients with AD and age-matched controls. Our clinical cohorts consisted of a well-characterized cohort of AD patients (n = 50; age, 60 ± 8 years) with positive AD biomarkers, and age-matched, cognitively unimpaired controls (n = 35; age, 63 ± 5.8 years). We identified the presence or the absence of epileptiform activity in AD patients (AD patients with epileptiform activity, AD-EPI+, n = 20; AD patients without epileptiform activity, AD-EPI-, n = 30) using long-term electroencephalography (LTM-EEG) and 1-hour long magnetoencephalography (MEG) with simultaneous EEG. Using the source reconstructed MEG data, we computed gamma PAC as the coupling between amplitude of the gamma frequency (30-40 Hz) with phase of the theta (4-8 Hz) and alpha (8-12 Hz) frequency oscillations, within entorhinal and parahippocampal cortices. We found that patients with AD have reduced gamma PAC in the left parahippocampal cortex, compared to age-matched controls. Furthermore, AD-EPI+ patients showed greater reductions in gamma PAC than AD-EPI- in bilateral parahippocampal cortices. In contrast, entorhinal cortices did not show gamma PAC abnormalities in patients with AD. Our findings demonstrate the spatial patterns of altered gamma oscillations indicating possible region-specific manifestations of network hyperexcitability within medial temporal lobe regions vulnerable to AD pathophysiology. Greater deficits in AD-EPI+ suggests that reduced gamma PAC is a sensitive index of network hyperexcitability in AD patients. Collectively, the current results emphasize the importance of investigating the role of neural circuit hyperexcitability in early AD pathophysiology and explore its potential as a modifiable contributor to AD pathobiology.

Electronically Tunable Sinusoidal Oscillator Using Only Single Current-Controlled Current Conveyor Trans-Conductance Amplifier

This work presents a wide frequency range sinusoidal oscillator design that relies on only one active component, a current-controlled current conveyor trans-conductance amplifier, and a few passive components. It just employs two grounded and non-floating capacitors and one resistor to complete the procedure. This design has the advantage of allowing the oscillation frequency and condition to be adjusted not only electronically, but also separately, without affecting the values of any passive components. To verify the functionality and usefulness of the developed sinusoidal oscillator circuit, ORCAD PSPICE simulations are done using 0.18 um process parameters for complementary metal oxide semiconductor technology. The obtained results demonstrate its application to a wide range of frequency generation without the need for additional components, hence validating the theoretical expectation.

Study of oscillation characteristics for quartz crystal oscillators based on equivalent multi‐physics model

AbstractIn recent years, high‐performance quartz‐crystal oscillators (XOs) for integrated circuits have been receiving considerable attention due to their featuring low voltage and high‐frequency stability. However, recent studies tend to focus solely on the impact of temperature as a single factor on crystal oscillator circuits, overlooking the circuit structure of the crystal oscillator itself. In this paper, a novel four‐parameter crystal model of XOs is detailed demonstrated, and analyzed to interpret typical XO oscillation characteristics at room temperature. The relationship between the RLC circuit and the oscillation was investigated. Meanwhile, the study delves into the various factors that influence oscillation behavior, paving the way for a comprehensive understanding of XOs' performance characteristics. temperature sweep simulations were induced to verify the theory and found that the parameter drift and thermal perturbation are close to the theory we proposed, which can be applied in temperature‐compatible XOs. The significance of this study lies not only in its contribution to the design and implementation of compact footprint XOs in the oscillator circuit platform but also in its provision of experimental evidence for fabricating wide temperature range compensated XO devices. The results show that the capacitance in the equivalent model of a crystal oscillator plays a dominant role in shaping the output waveform and exhibits relatively good temperature stability characteristics and serve as a valuable resource for engineers and researchers working on improving the performance and reliability of XOs, ultimately enabling the development of more advanced and efficient integrated circuits.

Electrochemical Synthesis of Sound: Hearing the Electrochemical Double Layer.

Electrochemical double layers (EDLs) govern the operation of batteries, fuel cells, electrochemical sensors, and electrolyzers. However, their invisible nature makes their properties and function difficult to conceptualize, creating an impediment to the broader understanding of double-layer function required for future technologies in energy storage and chemical synthesis. To render the behavior of electrochemical interfaces more intuitive, we made the rearrangement of interfacial components audible by employing the EDL as a variable element in a relaxation oscillator circuit. Connecting the circuit to a speaker generated an audible output corresponding to the change in potential resulting from EDL rearrangement. Variations in the applied voltage, electrolyte concentration and identity, as well as in the electrode material, yielded audible frequency variations that provide an intuitive understanding of EDL behavior. We expect that hearing the trends in behavior will provide a helpful and alternative method for understanding molecular movement at the electrochemical interface.

Design and Study the Performance of a CMOS-Based Ring Oscillator Architecture for 5G Mobile Communication

Oscillator circuits are used to make accurate and reliable clock signals for systems as simple as a wristwatch and as complicated as satellites, which are important for long-distance communication. There are many ways to build an oscillator circuit, using either passive or active parts. Each option has pros and cons, but at the current level of mobile communication development, the most important things are interoperability and low power use. This need has driven the development of compact, battery-operated electronics, and Very Large-Scale Integration (VLSI)-based ring oscillators provide the ideal solution. These oscillators ought to dissipate less power, have a large tuning range, and be compact. The paper presents a novel Complementary Metal Oxide Silicon (CMOS) ring oscillator that serves as a Voltage Controlled Oscillator. The suggested architecture utilizes the advantages of both a current-starved ring oscillator and a negative-skewed delay by combining their constituent parts. The proposed architecture has a control voltage of 1.15 V and a supply voltage of 2 V, generating a 9.35 GHz dominant frequency with a 13.82% harmonic distortion between the inputs and outputs. The proposed architecture can implement 5G-based applications that require high frequency and low power by carefully selecting the passive components within the design. Doi: 10.28991/ESJ-2024-08-01-020 Full Text: PDF

Sawtooth Signal Generator Using a Carbon-Based Memristor

It is possible to use the new electronic circuit element memristor in analog applications. Memristors or memristor emulators have already been applied in analog applications such as amplifiers, filters, oscillators, and chaotic circuits. In literature, it has been recently demonstrated that a memristor-based sawtooth signal generator can be built utilizing a memristor emulator and simulations with various memristor models. Such a sawtooth signal generator needs experimental verification with a memristor. Self-Directed Channel (SDC) Carbon-based Memristors are in the market now. Once, the memristor technology is mature enough, its applications may also follow soon. Any memristor application should be realized with a memristor, not an emulator. Knowm memristor has not been used to design a sawtooth signal generator in the literature previously. The aim of the study is to show that a sawtooth signal generator can be made using a Self-Directed Channel (SDC) Carbon-based Memristor and to examine it experimentally. The performance of this sawtooth signal generator is evaluated. The waveforms of the proposed circuit are also examined by varying its operating frequency. The simulation and experimental results are compared. It has been found that its waveforms can be predicted well up to 350 kHz and its high-frequency behavior is not predicted well above 350 kHz by the memristor model used.

A high frequency alternating current heater using the advantages of a damped oscillation circuit for low voltage Li-ion batteries

A Li-ion battery heater uses the battery's energy for heating, enabling subzero charging by integrating a power electronic system within the battery management system and increasing efficiency through the use of an oscillation circuit.