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New analytical equations are presented for amplitude analysis of metal-oxide-semiconductor (MOS) Colpitts oscillator. These equations are obtained from a large signal analysis that includes MOS operation in the saturation, triode ...
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New analytical equations are presented for amplitude analysis of metal-oxide-semiconductor (MOS) Colpitts oscillator. These equations are obtained from a large signal analysis that includes MOS operation in the saturation, triode and cutoff regions. The analysis is based on a reasonable estimation for the output voltage waveform. The estimated waveform must satisfy the nonlinear differential equations governing the circuit. The validity of the proposed method and the resulting equations has been verified through simulations using TSMC 0.18 um complementary MOS process. The results are also compared with the other methods. Simulation results show high validity of the proposed equations.
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In distributed oscillators, a large or infinite number of voltage and current variables that represent an oscillating electromagnetic wave are perturbed by distributed noise sources to result in phase noise. Here we offer an expli...
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In distributed oscillators, a large or infinite number of voltage and current variables that represent an oscillating electromagnetic wave are perturbed by distributed noise sources to result in phase noise. Here we offer an explicit, physically intuitive analysis of the seemingly complex phase-noise process in distributed oscillators. This study, confirmed by experiments, shows how the phase noise varies with the shape and physical nature of the oscillating electromagnetic wave, providing design insights and physical understanding.
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Hollow particles contain a void structure and exhibit unique properties, such as greater thermal and acoustic insulation properties, a lower dielectric constant, and distinct optical properties. Among various hollow particles, tho...
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Hollow particles contain a void structure and exhibit unique properties, such as greater thermal and acoustic insulation properties, a lower dielectric constant, and distinct optical properties. Among various hollow particles, those in which the shell material is silica are called hollow silica particles. In this study, we fabricated silica hollow particles by generating microbubbles with an ultrasonic generator. A silica shell was formed at the gas—liquid interface of microbubbles because of hydrolysis and condensation of methyltrimethoxysilane (MTMS), resulting in the formation of hollow silica particles. In addition, we examined the effect of changing the concentration of MTMS vapor in the dry air and the type of carrier gas on the hollow particle formation. As a result, it has been revealed that the adjustment of the MTMS vapor concentration leads to an increase in the yield of hollow silica particles. It has also been shown that the yield of hollow particles is improved by changing the carrier gas to one with low solubility in the liquid.
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This paper shows that the Toda oscillator can be converted to a new Helmholtz-Fangzhu equation, which is solved by the homotopy perturbation method with three expansions. The solution, the negative frequency and the damping rate a...
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This paper shows that the Toda oscillator can be converted to a new Helmholtz-Fangzhu equation, which is solved by the homotopy perturbation method with three expansions. The solution, the negative frequency and the damping rate are expanded into power forms in the homotopy parameter, the solution process is given step by step, and the results are of high accuracy. This paper gives a general approach to damp vibrations with singular terms,especially to the Helmholtz-Fangzhu oscillator.
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Localized neural populations in different brain areas can undergo periodical external influence. To study this situation we consider the well known model by Wilson and Cowan (1972). It describes the evolution of two interconnected...
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Localized neural populations in different brain areas can undergo periodical external influence. To study this situation we consider the well known model by Wilson and Cowan (1972). It describes the evolution of two interconnected neuronal subpopulations of excitatory and inhibitory neurons correspondingly. Besides, it could be considered as a model of an abstract self-regulatory system. We describe and reveal underlying mechanisms of two regimes of forced oscillations in the model. In the first one the system acts as a phase comparator, demonstrating high sensitivity to a value of a phase shift between inputs to excitatory and inhibitory neurons. In the second regime it acts similar to a low pass filter: amplitudes of forced oscillations of the both components are not small and almost constant for low frequencies of the external input to the excitatory subpopulation. But they decrease significantly when the frequency becomes rather high. For simplified versions of the model analytical estimates for corresponding ranges of parameters are derived. It is shown that they are in good agreement with the results of computer simulations. (C) 1997 Elsevier Science Ireland Ltd.
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A novel nonautonomous chaotic oscillator based on the passive structure of Chua's circuit is proposed. Unlike most of the available members of this class of chaotic oscillators, the proposed circuits is driven by a periodic pulse-...
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A novel nonautonomous chaotic oscillator based on the passive structure of Chua's circuit is proposed. Unlike most of the available members of this class of chaotic oscillators, the proposed circuits is driven by a periodic pulse-train rather than by sinusoidal excitation. This results in equilibrium points which have fixed positions in space. The circuit employs self feedback via a single comparator, which is the only nonlinear device involved. The output of this comparator is a chaotic bipolar pulse-train.
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A new circuit for a simple resistorless quadrature oscillator is proposed in this work. The circuit consists of a single voltage dependant transconductance amplifier block and two grounded capacitors which ease IC fabrication. The...
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A new circuit for a simple resistorless quadrature oscillator is proposed in this work. The circuit consists of a single voltage dependant transconductance amplifier block and two grounded capacitors which ease IC fabrication. The workability of the circuit has been verified using 180 nm CMOS based TSMC Technology. Moreover, an experiment is performed using a prototype assembled using a commercially available operational transconductance amplifier IC LM3080.
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In this study, various mode of oscillations in two coupled van der Pol oscillators with ninth-power nonlinear characteristics are investigated. At first, a van der Pol oscillator with ninth-power nonlinear characteristics is desig...
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In this study, various mode of oscillations in two coupled van der Pol oscillators with ninth-power nonlinear characteristics are investigated. At first, a van der Pol oscillator with ninth-power nonlinear characteristics is designed. In the computer simulations, the characteristics are modeled by both piecewise-linear and smooth polynomial. For both cases, we confirm that the oscillator exhibits hard oscillations and that two sizes of limit cycles coexist. Next, the generation of various modes of oscillations are investigated for the case that two oscillators with ninth-power nonlinear characteristics are coupled by an inductor. Since coupled systems of such oscillators with hard nonlinearity are known to have doublemode oscillations, the present system is expected to generate various modes of oscillations. By computer simulations and circuit experiments, we confirm the generation of several doublemode oscillations with different modes.
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An early result by Markus and Weerasinghe (1988) concerning the oscillatory behavior of simple harmonic oscillators driven by random forces is extended to the general class of coupled stochastic harmonic oscillators. The ability o...
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An early result by Markus and Weerasinghe (1988) concerning the oscillatory behavior of simple harmonic oscillators driven by random forces is extended to the general class of coupled stochastic harmonic oscillators. The ability of numerical discretizations - as discrete dynamical systems - for reproducing this oscillatory property of the continuous systems is also considered, which complements a recent study by de la Cruz et al. (2017) for simple stochastic harmonic oscillators. (C) 2018 Elsevier B.V. All rights reserved.
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The comprehensive formularization of the frequency–amplitude formula is the main interest in this work to cover higher powers of the restoring force which are not limited to cubic powers. Three equivalent styles of the generalize...
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The comprehensive formularization of the frequency–amplitude formula is the main interest in this work to cover higher powers of the restoring force which are not limited to cubic powers. Three equivalent styles of the generalized frequency amplitude have been performed. In addition, the restoring force is not restricted to an odd function in which the nonsecular forces are included. Three forms of the non-secular forces have been formulated for the first time and treated as non-homogenous of the linearized Duffing oscillator. The modified style of He's formula has been applied to the singular oscillator using the enhanced potential function. The simplicity of the present approach provides extra advantages for high nonlinearity vibration. This method enriches the analysis with more details in new dimensions.
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