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Confined impinging jets (CIJs) are highly efficient mixers. The scales of mixing in CIJs are controlled by the opposed jets interaction. A mechanistic model is described here, which accurately predicts the impinging position of the opposed jets for a large range of flow rate ratios. The impinging point position is shown to impact the dynamic properties of the flow and the achieved mixing quality. The opposed jets kinetic energy ratio is shown to have a critical impact on mixing, similar to the Reynolds number. A mixing chamber design relation is proposed and verified for the opposed injectors diameters ratio [ABSTRACT FROM AUTHOR]

ABSTRACT This paper analyzes the stability criteria for closed loop tracking in a GNSS receiver using Bode analysis techniques. This defines the stable limits of predetection integration time (T) for a given loop filter design, including its order and noise bandwidth (Bn) in combination with all of the other components involved in the closed receiver tracking loop. The loop filter design used in this paper is based on a traditional analog design converted to digital using the bilinear transform. The shortcomings of this traditional design are briefly described, but the traditional design suffices for small T and ample phase margin. Clearly, a pilot channel in modern GNSS signals permits much longer T than allowed by the original GPS data channels, but the stability assurance must be considered in either case. The methodology applies to both data (Costas) and data-less (pilot) tracking loops. Additional insight is provided using the results of this analysis. Copyright © 2014 Institute of Navigation. [ABSTRACT FROM AUTHOR]

An analog behavioral model of high power gate turn-off thyristor (GTO) is developed in this paper. The fundamental methodology for the modeling of this power electronic circuit is based on the use of the realistic diode consideration of non-linear junctions. This modeling technique enables to perform different simulations taking into account the turn-on and turn-off transient behaviors in real-time. The equivalent circuits were simulated with analog software developed in our laboratory. It was shown that the tested simple and compact model allows the generation of accurate physical characteristics of power thyristors under dynamic conditions. The model understudy was validated with analog simulations based on operational amplifier devices. [ABSTRACT FROM AUTHOR]

Parallel simulation is an efficient way to cope with long runtimes and high computational requirements in simulations of modern complex integrated electronic circuits and systems. This paper presents an algorithm for parallel simulation based on parallelization in equation formulation and simultaneous calculation of matrix contributions for nonlinear analog elements. In addition, the paper describes the development of a grid interface for a parallel simulator that enables a designer to perform simulations on distant computer clusters. Performances of the developed parallel simulation algorithm are evaluated by simulation of a microelectromechanical system. [ABSTRACT FROM AUTHOR]

A new meta-material element that can realize axis-independent negative permeability is proposed and analyzed. The element is constructed as an intuitive 3D analog of the well-known flat split-ring structure (SRR). Unlike the SRR, the proposed element exhibits negative permeability for three preferred coordinate axes, and therefore enables meta-material applications such as focusing and efficient radiation from electrically small structures in multiple directions within the same structure. In addition, it is shown that the addition of lumped-circuit components to the element enables both tunability and functionality at very small sizes, far from the intrinsic resonance of the structure itself. The designed element is then simulated rigorously using a previously reported integral-equation technique that includes the ability to model linear and nonlinear tuning elements attached to the meta-material elements. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 530–533, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20687 [ABSTRACT FROM AUTHOR]

Holographic reduced representations (HRRs) are a method for encoding nested relational structures in fixed-width vector representations. HRRs encode relational structures as vector representations in such a way that the superficial similarity of the vectors reflects both superficial and structural similarity of the relational structures. HRRs also support a number of operations that could be very useful in psychological models of human analogy processing: fast estimation of superficial and structural similarity via a vector dot-product; finding corresponding objects in two structures; and chunking of vector representations. Although similarity assessment and discovery of corresponding objects both theoretically take exponential time to perform fully and accurately, with HRRs one can obtain approximate solutions in constant time. The accuracy of these operations with HRRs mirrors patterns of human performance on analog retrieval and processing tasks. [ABSTRACT FROM AUTHOR]

The article discusses the validity of stochastic control theory application to the Static Var Compensator (SVC) firing control scheme. After conducting analog simulations, linear time-variant stochastic model can be applied to the disturbance component in the SVC control system for an arc furnace power supply system. The variance of the compensation error decreased to 14%, promoting the validity of the stochastic model. A one-board computer and additional circuits were used to conduct configuration used in stochastic method.

FM demodulators using digital signal processing (DSP) technology are advantageous over analog type FM demodulators because they have stable behavior, high-reliability, compactness by LSI, and no need for adjustment. In this paper, we propose a new FM demodulator called SIN type FM demodulator which uses DSP technology. It reduces hardware complexity compared with TAN type FM demodulator which has the best characteristic among many FM demodulators using DSP. For example, SIN type needs only one A/D converter, while TAN type needs two. As for ROM, SIN type needs one-third of ROM which TAN type requires. The circuit of SIN type required for phase detector is substantially simplified. First, the circuit configuration and operation principle of SIN type will be described and SIN type circuit is shown to be significantly simplified compared with TAN type circuit. Then, compared with TAN type circuit. Then, through computer simulation the performance of SIN type is shown to be much better than the Digital Quadrature type, which has the simplest structure of all the FM demodulators using DSP. [ABSTRACT FROM AUTHOR]

With the growth of video conferencing, the need for multipoint conferences is also growing. In a multipoint videoconference over a wide-area network, the users are connected to a multipoint control unit (MCU) in a central office. A video bridge in the MCU combines the input video streams into a suitable format for presentation. In this article, we discuss various approaches of video bridging for continuous presence multipoint video conferencing. We also discuss the video quality issues and describe some multipoint video bridge prototypes we have developed. © 1997 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 8, 427–431, 1997 [ABSTRACT FROM AUTHOR]

Current-mode CMOS analog defuzzification circuits previously proposed are insensitive to absolute variation of the fabrication process and are easy to expand into a multiple-input circuit. However, they have two disadvantages. One is that they need two input currents which are equal in magnitude and opposite in direction (sign). A current steering circuit which consists of current mirrors is used for changing the direction of the input current signals. However, because current mirrors are strongly influenced by channel length modulation effect, it is very difficult to generate the desired current signal. The other disadvantage is that they need input bias currents for all input signals, which causes high power consumption. In this paper, a current-mode CMOS analog four-quadrant multiplier for defuzzification circuits is proposed. The proposed multiplier is insensitive to absolute variation of the fabrication process. Furthermore, it removes the above disadvantages. A defuzzification circuit using the proposed multiplier is designed. The proposed defuzzification circuit is improved to reduce power dissipation by using a common bias block circuit. These circuits are analyzed in detail by the PSPICE System. The proposed defuzzification circuit is evaluated and its validity is discussed. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(6): 30–41, 1997 [ABSTRACT FROM AUTHOR]

In an oscillatory circuit containing a nonlinear negative resistor whose v-I relationship is I = -g1v + g3v³, under certain conditions. However, it can be confirmed experimentally and theoretically that excitation can exit when the resistor is biased and periodically switched by an along switch a much higher frequency than both resonant and external frequencies. The oscillation modes obtained changes in the order trivial, hard, soft, hard and trivial as external force increase. This mode variation has been found to be same as that in I = g, 1v-g3 + g5v5, except for the hard oscillation. [ABSTRACT FROM AUTHOR]

A measurement-based nonlinear MESFET model is presented, where the large-signal model is constructed from measured small-signal 5 parameters and dc characteristics. An automatic optimization process is used for finding suitable values for the parasitic components and the intrinsic current sources. The intrinsic model is created with the use of frequency-dependent current sources. The model and the automatic model generator have been implemented in APLAC (analog circuit simulator and design tool) [1]. [ABSTRACT FROM AUTHOR]

The harmonic balance method is a technique for the numerical solution of nonlinear analog circuits operating in a periodic, or quasi-periodic, steady-state regime. The method can be used to efficiently derive the continuous-wave response of numerous nonlinear microwave components including amplifiers, mixers, and oscillators. Its efficiency derives from imposing a predetermined steady-state form for the circuit response onto the nonlinear equations representing the network, and solving for the set of unknown coefficients in the response equation. Its attractiveness for nonlinear microwave applications results from its speed and ability to simply represent the dispersive, distributed elements that are common at high frequencies. The last decade has seen the development and application of harmonic balance techniques to model analog circuits, particularly microwave circuits. The first part of this article reviewed the fundamental achievements made during this time. In this part, the extension of the method to quasi-periodic regimes, optimization analysis, oscillator analysis, studies of various convergence strategies, and practical applications are discussed. A critical assessment of the various types of harmonic balance techniques is given. Examples of designs which have been modeled using the harmonic balance technique and built both in hybrid and MMIC form are presented. [ABSTRACT FROM AUTHOR]

An analog computer model of the endosomatic galvanic skin response has been constructed from a theoretical interpretation of end organ function and has been used to study some of the parameters of a response consisting of two opposing components. The results demonstrate that the interaction between the faster negative component and the slower positive component can produce triphasic patterns as well as alterations in maximum deflection and rates of rise and decay. The character and degree of alteration of the negative component is shown to be heavily dependent on the amplitude and time delay of the positive component. The possible application of this model in the development of an automatic analyzer is considered. [ABSTRACT FROM AUTHOR]

A new self-compensation technique is proposed for eliminating subharmonic oscillation and chaotic regimes in dc–dc switching converters under peak current mode control. The proposed method extracts a control signal from the error between the inductor current and a suitable reference and does not require an external signal generator as in the conventional ramp compensation scheme. The analytical expressions of the control domain using Filippov method are obtained. Simulation results show that the proposed technique can be implemented using standard analogue devices and can effectively eliminate subharmonic and chaotic oscillations and can ensure a stable operation for a wide range of the duty ratio. [ABSTRACT FROM AUTHOR]

Automatic generation and numerical integration of network equations are the core of industrial TCAD packages for analog simulation of highly integrated circuits [1]. Many packages supply the Jacobian with every function evaluation at very low additional costs: it is about only 1.4 times more expensive to evaluate both right-hand side and Jacobian than right-hand side alone. In this paper we discuss four different approaches to use the cheap Jacobian information within a ROW-type integration scheme, mainly with respect to stability. [ABSTRACT FROM AUTHOR]