A network of electronic neural oscillators reproduces the dynamics of the periodically forced pyloric pacemaker group

Low-dimensional oscillators are a valuable model for the neuronal activity of isolated neurons. When coupled, the self-sustained oscillations of individual free oscillators are replaced by a collective network dynamics. Here, dynamical features of such a network, consisting of three electronic implementations of the Hindmarsh-Rose mathematical model of bursting neurons, are compared to those of a biological neural motor system, specifically the pyloric CPG of the crustacean stomatogastric nervous system. We demonstrate that the network of electronic neurons exhibits realistic synchronized bursting behavior comparable to the biological system. Dynamical properties were analyzed by injecting sinusoidal currents into one of the oscillators. The temporal bursting structure of the electronic neurons in response to periodic stimulation is shown to bear a remarkable resemblance to that observed in the corresponding biological network. These findings provide strong evidence that coupled nonlinear oscillators realistically reproduce the network dynamics experimentally observed in assemblies of several neurons.     

Role of elastic dissipation in the formation of the resonant properties of magnetization precession in the magnetoelastic environment

A set of coupled magnetoelastic equations is used to examine the problem concerning the establishment of free magnetization oscillations under the condition that dissipation is lacking in the magnetic system. The critical relationship between elastic damping parameters and the magnetoelasticity constant, which corresponds to the minimum in the dependence of magnetic damping on elastic one, is found. The bellshaped peak, on both sides of which the influence of an elastic system on the magnetic one diminishes, is detected in the dependence between the effective magnetic oscillation damping parameter and the elastic oscillation damping parameter. The observed phenomena is suggested to interpret using the model of two (magnetic and elastic) oscillators coupled through magnetoelastic interaction. The given model makes it possible to reveal four regimes of steady-state oscillations: weak damping with beats, strong damping without beats, weak damping without beats, and supercritical exponential growth. The mechanical similarity of observed phenomena is discussed, and recommendations needed to organize experiments are proposed.     

Self-oscillating systems with chaotic dynamics based on the van der Pol-Duffing equations

Mathematical models of the systems of the coupled van der Pol-Duffing equations with the chaotizing feedback algorithm (CFA) and the parametric chaotization algorithm (PCA) are considered. Numerical methods are used to analyze particular cases of the systems that do not employ the CFA and have mutual or unidirectional resistive coupling. The chaotic modes formed under asynchronous interactions of the oscillations of partial oscillators are considered. It is demonstrated that oscillations can be chaotized using the CFA or PCA when regular operating modes are realized in the absence of these algorithms.     

Avalanche effects in bulk InP microwave diode oscillators

An association with current runaway of nontransit frequency oscillations in bulk InP oscillators is plausibly interpreted as an avalanche generation process.     

Reply to comments on "Higher harmonic generation in CMOS/SOS ring oscillators"

Arguments presented in the referenced paper [1] imply that higher order modes of oscillation should not be expected in ring oscillators with a small number of stages. In contrast to this, third and fifth harmonic oscillations have been observed in 15-stage Si MESFET ring oscillators using BFL inverters. It is explained that the decay mechanism presented in the referenced paper applies primarily to even harmonics in ring oscillators with an even number of stages. Higher order modes of oscillation can be sustained in ring oscillators with a relatively small odd number of stages if the rise and fall times of the inverters used are short in comparison with their total delay.     

Nanoscale system dynamical behaviors: from quantum-dot-based cell to 1-D arrays

In this paper, we consider coupled quantum-dot cells, which are usually used for quantum-dot cellular automata, to build nanoscale dynamical systems. In particular, it is shown how the simple connection of few quantum-dot cells, quantum cellular nonlinear networks (Q-CNNs), can cause the onset of chaotic oscillations. Complex dynamics can be obtained only with small differences of polarizations and parameters. Local activity conditions are investigated for a two-cells case satisfying the criteria for the generation of complex spatio-temporal behaviors. The richness of dynamics of quantum CNNs is also emphasized through examples of synchronization in an array of so-built oscillators, in both cases of identical parameters and spatial dissymmetry.     

Broad-Band Bias-Current-Tuned IMPATT Oscillator for 100-200 GHz

Broad-band bias-current-tuned IMPATT oscillators rising harmonic oscillations have been realized for the short-millimeter wave-length region (100-300 GHz). The relationship between diode and wave-guide parameters (breakdown voltage, junction diameter, and waveguide cutoff frequency) to obtain broad-band tunable oscillations is investigated theoretically and experimentally. Consequently, a tuning bandwidth of 35 GHz is obtained with IMPATT oscillators in the 160-GHz band, and 30 GHz in the 200-GHz band.     

General stabilization techniques for microwave oscillators

A general stabilization technique is proposed to suppress undesired spurious oscillations in microwave oscillators. The purpose is to eliminate these oscillations while maintaining the oscillation frequency and amplitude of the originally-unstable solution. The main advantage of the technique is its wide generality of application, not restricted to low-frequency spurious oscillations. It has been tested on an unstable 18-GHz push-push oscillator that has been manufactured and measured, with very good agreement with the simulation results.     

Formation of space-time structures in an active-medium-wavefield system in a region with a semitransparent boundary

The interaction of an ensemble of active oscillators in a 2D wave field is simulated. It is concluded from the simulation results that oscillations in the system can be synchronized in the presence of the multimode interaction of the field and active medium when there is no wave attenuation.     

Investigation of parasitic oscillations in IMPATT-diode oscillators by a simple locus chart

Using a simplified theory of parasitic oscillations in IMPATT-diode oscillators, a locus chart is constructed that facilitates the study of parasitic oscillations of the degenerate type. Results of experiments on a high-Q factor coaxial/waveguide circuit (Kurokawa circuit) are explained by this locus chart.     

Operating principles of reactance-less memristor-based oscillators

The aspects of design of reactance-less oscillators based on memristors are considered. The requirements on load elements in the circuits of such oscillators are formulated. The equations describing the dynamical behavioral of the memristor oscillators with the use of linear-drift models are presented. Examples of the analysis and synthesis of oscillators using such equations are presented. The possibility of generation in the circuits under consideration of periodic signals with a waveform close to harmonic oscillations is shown.     

Control of state transitions in an in silico model of epilepsy using small perturbations

We propose the use of artificial neural networks in an in silico epilepsy model of biological neural networks: 1) to predict the onset of state transitions from higher complexities, possibly chaotic to lower complexity possibly rhythmic activities; and 2) to restore the original higher complexity activity. A coupled nonlinear oscillators model (Bardakjian and Diamant, 1994) was used to represent the spontaneous seizure-like oscillations of CA3 hippocampal neurons (Bardakjian and Aschebrenner-Scheibe, 1995) to illustrate the prediction and control schemes of these state transition onsets. Our prediction scheme consists of a recurrent neural network having Gaussian nonlinearities. When the onset of lower complexity activity is predicted in the in silico model, then our control scheme consists of applying a small perturbation to a system variable (i.e., the transmembrane voltage) when it is sufficiently close to the unstable higher complexity manifold. The system state can be restored back to its higher complexity mode utilizing the forces of the system's vector field.     

Transient processes under stochastic synchronization of oscillators in colored-noise medium

Equations that describe mutual and induced chaotic synchronization of n (n = 2, 3, 4,...) autooscillation systems in colored-noise medium are derived. It is demonstrated that external colored noise acting upon a system of coupled oscillators and a chain of unidirectionally coupled oscillators causes a decrease in the duration of transient processes that lead to the chaotic synchronization (both mutual and induced) of nonidentical oscillators and a decrease in the time needed for stabilization of the symmetric state of the system when the parameters of oscillators are identical.     

Analysis of interinjection-locked oscillators for integrated phased arrays

The behavior of a system of coupled oscillators is shown to have potential applications in the generation of power for integrated phased antenna arrays. Nonlinear differential equations are derived to describe a system of oscillators coupled by an arbitrary frequency-dependent network. State-variable analysis of the linearized equations leads to closed-form solutions for one- and two-dimensional phased array systems. Experimental data for a VHF prototype system is presented, and practical considerations in system design are discussed.     

A continuum model of the dynamics of coupled oscillator arrays forphase-shifterless beam scanning

The behavior of arrays of coupled oscillators has been previously studied by computational solution of a set of nonlinear differential equations describing the time dependence of each oscillator in the presence of signals coupled from neighboring oscillators. The equations are sufficiently complicated in that intuitive understanding of the phenomena which arise is exceedingly difficult. We propose a simplified theory of such arrays in which the relative phases of the oscillator signals are represented by a continuous function defined over the array. This function satisfies a linear partial differential equation of diffusion type, which may be solved via the Laplace transform. This theory is used to study the dynamic behavior of a linear array of oscillators, which results when the end oscillators are detuned to achieve the phase distribution required for steering a beam radiated by such an array     

非自治约瑟夫森结阵列的耦合同步研究

针对电阻-电容-电感分路的约瑟夫森结耦合的阵列,当驱动电流的相位差为零时,分析了对称振子之间完全同步流形及其稳定性.当相位差不为零时,计算了误差系统随相位差变化的分岔图和李雅普诺夫指数曲线,发现相位差破坏了振子对之间的完全同步,但却可以抑制系统中的混沌.理论上讨论了约瑟夫森结阵列中延迟同步的存在性,发现距离较远的振子对...     

Two-dimensional array beam scanning via externally and mutuallyinjection-locked coupled oscillators

The use of arrays of injection-locked voltage-controlled oscillators coupled to nearest neighbors has been proposed as a means of controlling the aperture phase of one and two-dimensional (2-D) phased-array antennas. It has been demonstrated both theoretically and experimentally that one may achieve linear distributions of phase across a linear array aperture by injection locking to an external oscillator the end oscillators of an array of a mutually injection-locked oscillators. These linear distributions cause steering of the radiated beam. It is demonstrated theoretically here that one may achieve beamsteering in a similar manner in two dimensions by injecting appropriately phased signals into the perimeter oscillators of a 2-D array. The analysis is based on a continuum representation of the phase previously developed in the context of beamsteering via tuning of the perimeter oscillators     

Self-Consistent Effects on the Starting Current of Gyrotron Oscillators

Self-consistent effects on the starting current of gyrotron oscillators are examined. Field profiles in the open cavity are shown to be sensitive to the interaction dynamics. This can either significantly raise or lower the oscillation threshold, particularly for the low-Q modes. The transition from resonant-mode oscillations at the low magnetic field to backward-wave oscillations at the high magnetic field is demonstrated.