bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new method for approximating passive network functions
Authors: Carlin H. J. , Kotiveeriah P. 
Published: June 2007

AbstractThe problem of efficiently approximating real frequency data, which represents either measured information of a physical system or idealized curves to be realized by rational positive real (PR) or bounded real (BR) functions is considered. The final rational function is guaranteed in advance to satisfy the conditions of physical realizability. All the steps of approximation are executed in the real frequency domain. Illustrative, numerical examples are given.
Low cost active low pass and band pass network
Authors: Attikiouzel J. , Linggard R. 
Published: June 2007

AbstractAn active RC filter circuit is described which realizes second order lowpass and bandpass functions. The filter uses two I.C. Operational amplifiers and four passive components to achieve accurate Q values up to 50. Its Q sensitivity to component values is found to be very low. The results of an exhaustive computer simulation are given which clearly define the operating limits of the circuit. A practical design technique is outlined, and a sixth order example is given.
The connection function–theory and application
Authors: Ransom M. N. , Saeks R. 
Published: June 2007

AbstractAn approach to circuit theory is presented wherein the connections are modelled as a system valued function of a system valued variable. It is shown that for a large class of circuits and systems that this nonlinear function can be viably represented by four matrices through which it may be readily manipulated, both theoretically and computationally. The elementary properties of the connection function are derived and the approach is illustrated through a number of applications. In particular, an explicit formula for the sensitivity of a circuit in terms of the sensitivity of its components is obtained; and a semi‐analytic solution to a class of CAD problems is formulated.
Short‐circuit admittance matrix synthesis with rc common‐ground networks and a minimum number of grounded finite‐gain phase‐inverting voltage‐controlled voltage sources
Authors: Stamenković Borivoje B. 
Published: June 2007

AbstractA new procedure for the synthesis of active RC networks when grounded finite‐gain phase‐inverting voltage‐controlled voltage sources serve as active elements is developed. It is proved that an arbitrary n × n matrix of real rational functions of the complex frequency variable can be realized as the short‐circuit admittance matrix of a grounded transformerless active RC n‐port network containing (n+1) grounded finite‐gain phase‐inverting voltage‐controlled voltage sources (VCVSs). In general all the (n+1) grounded VCVSs are necessary.The structure proposed to prove a general theorem is later simplified for the realization of a restricted but important class of real rational matrices to obtain considerable savings in the computation volume and in the number of passive components used for the realization of the network.Examples are given to illustrate presented synthesis procedures.
Finite band approximation for distributed and digital selective linear phase transfer functions
Authors: Fahmy M. F. , Rhodes J. D. 
Published: June 2007

AbstractUsing the recently derived formula which interpolates to a linear phase response at equidistant frequency intervals in a distributed variable, transfer functions are constructed which exhibit flat amplitude and linear phase characteristics over a finite band.Reciprocal realizations for the implementation in distributed structures are derived, together with a non‐reciprocal version ideally suited for recursive digital filter design. Their superiority over the corresponding maximally flat solutions is also illustrated.
Transfer matrix realization using RC:GIC Networks
Authors: Mitra S. K. 
Published: June 2007

AbstractA general synthesis procedure for realizing any stable voltage transfer matrix using current‐conversion type generalized impedance converter (GIC)s is outlined. Each row of the transfer matrix is realized separately as an M‐input, single‐output grounded RC:GIC network where M is the number of columns in the transfer matrix. The realization procedure is illustrated by an example. Using this approach, a second‐order filter has been obtained capable of realizing simultaneously highpass, band‐pass and low‐pass transfer functions and using fewer passive components and operational amplifiers than the popular state‐variable realizations. The various sensitivities of the second‐order realizations are low and comparable to the state‐variable realizations. A similar method can be developed for current transfer matrix invoking duality and thus using the voltage‐conversion type GICs.
General nonlinear equation for LMCR oscillators and its nearly sinusoidal solutions
Authors: Sidorowicz R. S. 
Published: June 2007

AbstractA generalized feedback oscillator consisting of an ideal nonlinear amplifier and a linear, passive or active LMCR network is considered. The network is of second order and has a ‘biquadratic’ voltage transfer function.Though such a system represents a large family of important oscillators, it appears that an explicit nonlinear differential equation for it is not known. Consequently, a general nonlinear differential equation, valid for all possible second‐order oscillators is derived. This contains explicitly all the network and amplifier parameters. The van der Pol equation is shown to be a special case of the general equation and to represent the simplest second‐order oscillator. Transient and steady‐state solutions of the general equation are obtained for the case of nearly sinusoidal oscillations. The solutions provide explicit expressions for the transient rise time, steady‐state amplitude, harmonic content and the frequency instability of the oscillator output waveform. The expressions can be used to analyse and evaluate all possible types of second‐order oscillators. A figure of merit for the oscillator network is defined, and the conditions to be met by the amplifier and the network in order to produce oscillations are determined. Validity of the formulas is verified experimentally by means of two representative oscillators.
Order of complexity of rlc networks containing a reactive gyrator
Authors: Milić Mirko M. 
Published: June 2007

AbstractUsing a particular expansion of the network determinant, a simple formula is derived giving the total number of natural frequencies of a passive RLC network containing a reactive gyrator. The order of complexity is expressed in terms of the degrees of the polynomials in the gyration impedance and the alteration in the network topology due to gyrator embedding. Quantitative conditions for the order of complexity of the active network exceeding that of the network without the gyrator are obtained. Formulas are also derived for the number of zero and non‐zero natural frequencies.
Differential sensitivity after large changes in network elements
Authors: Sud D. 
Published: June 2007

AbstractThis paper presents a method for the calculation of first‐ and higher‐order differential sensitivities of the response of a linear reciprocal or non‐reciprocal network following large changes to one or more elements. The method requires only one nodal matrix inversion per frequency. The same inverted matrix can be used when different elements are chosen for large change, providing the original changed element(s) is returned to its nominal value.
Some aspects of band‐pass filter design pertaining to amplifier imperfections and mass production
Authors: Zeheb Ezra 
Published: June 2007

AbstractA multiple feedback single amplifier realization of a second order band‐pass filter is considered, with certain assumptions made on the amplifier imperfections. The required component values are derived explicitly in terms of the desired filter parameters, the amplifier's open loop finite gain and a degree‐of‐freedom.The feasible range of the degree‐of‐freedom is derived. It is then used to either minimize variations of filter parameters due to changes in passive and active components (assuming properties pertaining to hybrid technology components), or minimize the variance of the filter parameters relative variations, in order that all mass produced filter sections of the same type will be similar to each other.For the first case, some useful observations are made concerning the behaviour of the filter under environmental changes, and the allocation of gain to various sections of a cascade filter. Experimental results are reported and compared to anticipated ones.
Piecewise linear approximation of nonlinear oscillators
Authors: Iñigo Rafael M. 
Published: June 2007

AbstractDifferential equations to represent electronic amplifier oscillators have been developed by van der Pol and Scott using a cubic and an arctangent approximation for the amplifier transfer characteristic, respectively. Using a piecewise linear approximation for the transfer characteristic results in more accurate solutions, independently of the amplitude of the oscillations and does not require to determine the coefficients for the approximations, usually a difficult problem.
A new approach to the network modelling of capacitive irises and steps in waveguide
Authors: Rozzi T. E. 
Published: June 2007

AbstractClassical network representations of waveguide discontinuities assume monomode operation and involve elements which depend not only upon geometry, but also on frequency.Later approaches to the problem consist of numerical techniques. These are unsuitable for synthesis since they do not yield equivalent networks and involve repeating the field analysis at each frequency, which is cumbersome for applications to wideband design.A recent approach permits to derive wideband equivalent networks with elements which depend only upon geometry. In this contribution capacitive irises, steps and combinations are treated. These discontinuities occur in filters, transformers, etc. where higher‐order mode interaction cannot be neglected for closely spaced discontinuities. Whatever this spacing may be, higher order mode interaction always occurs in oversize guide. Higher order mode interaction fits naturally into the network modelling presented here. The resulting network representations are either in canonical Foster form of the first type or easily reducible to it. This approach is based on a Rayleigh–Ritz variational solution of the field problem and involves manipulations with small matrices only.The accuracy of the method is demonstrated for a number of basic configurations, while its flexibility is illustrated by providing simpler equivalent networks, applicable when extreme accuracy is not required. The elements involved are given in graphical or in simple analytical form.
Optimization of the dynamic range and the noise distance of RC‐active filters by dynamic programming
Authors: Lueder E. 
Published: June 2007

AbstractRC‐active filters are usually realized by cascading 2nd order stages. The degrees‐of‐freedom in this procedure are: the pole‐zero assignments to form the second order transfer functions, the gain‐factors for the stages and the sequence in the cascade. These freedoms will simultaneously be used to maximize the dynamic range and the noise distance of the filters. The exact solution to the problem will be obtained by dynamic programming. A rule of thumb avoiding a computer program and an example are given.
Solving piecewise‐linear equations for resistive networks
Authors: Chien M. J. , Kuh E. S. 
Published: June 2007

AbstractNonlinear resistive networks can be characterized by the equation f(x)= y where f(x) is a continuous piecewise‐linear mapping of Rn into itself. The n‐dimensional Euclidean space is divided into a finite number of regions, and, in each region say region Rm, we can express f by J(m)x + w(m) where J(m) is a constant n × n Jacobian matrix and w(m) is a constant n‐vector. In this paper we obtain the following results:If all the Jacobian determinants in the unbounded regions have the same sign, the equation f(x)= y has at least one solution and an algorithm is developed, which obtains one or more solutions in a finite number of steps. The work represents a generalization of early work by Fujisawa, Kuh and Ohtsuki and relaxes the condition imposed on the function. For example, in the bounded regions, the Jacobian matrices can be singular and the sign of Jacobian determinants can be arbitrary.
A new canonic realization of lossless immittance functions using six‐element sections
Authors: Ramachandran V. , Swamy M. N. S. 
Published: June 2007

AbstractA new canonic realization cycle for lossless driving point immittance functions is given. This is achieved by extracting a six‐element section (involving three inductors and three capacitors), which is terminated in a simpler immittance function whose form is the same but of order six lower than that of the original. This method is easily extended to RC and RL cases.
On a class of nonlinear networks
Authors: Matsumoto T. 
Published: June 2007

AbstractSome of the properties of a class of nonlinear networks are discussed. The class of networks under consideration is allowed to have very general branch characteristics including couplings among elements of different kinds and discontinuities in time. Firstly, local existence and uniqueness of solutions to the state equations are discussed. Secondly, several global properties of the class of networks are discussed. Some of the properties of the degree of a function and a differential property of implicit function theorem turn out to be useful.
General interpretation of sensitivity functions
Authors: Solymosi J. , Trón T. 
Published: June 2007

AbstractA general interpretation of sensitivity functions of linear networks is given in order to determine any nth order sensitivity function with respect to any parameter. The calculation uses an indirect method: ‘transfer function products’ give the desired sensitivities instead of derivation. The interpretation makes it possible to construct a computer program, too, which needs only one matrix inversion for a complete sensitivity analysis (including first‐ and higher‐order sensitivities). It is shown that the adjoint network approach is superfluous and more complicated than the given method.
The generalized tree for state variables in linear active networks
Authors: Mark Shew‐Kin , Swamy M. N. S. 
Published: June 2007

AbstractA tree for the association of state variables in linear active networks is presented. This tree is selected in such a manner that the voltages across the capacitors contained in it and the currents through the inductors contained in its cotree may be chosen as state variables of a linear network. An algorithm for finding such a tree is given, and the association of state variables with this tree are demonstrated by examples.
Equal ripple tolerance characteristics
Authors: Neirynck Jacques , Milić Ljiljana 
Published: June 2007

AbstractThe concept of equal ripple tolerance is introduced and justified in the particular case of the polynomial low pass filter. By comparison with the classical Chebyshev characteristic, it is shown that it is possible to improve the tolerance to element variations by a factor 2. The ultraspherical polynomial provides a closed form specification which is significantly better than the Chebyshev characteristic.
Contribution to the theory of weakly nonlinear oscillators: Part I. An estimation of amplitude and frequency
Authors: Kudrewicz J. 
Published: June 2007

AbstractSteady state signal in an oscillator is described by a nonlinear integral equation. A new theorem on the existence of an isolated number ω, for which the equation has a periodic eigensolution of period 2π/ω is given in the paper. An approximate value ω and approximate eigensolution can be easily obtained by the describing function method. The main result of the paper is the presentation of an effective estimation of the error of this approximation for weakly nonlinear oscillators.
A quasi‐steady‐state approach to the generation of non‐sinusoidal orthogonal waveforms at microwave frequencies
Authors: Jackson J. Russell , Rhodes J. David 
Published: June 2007

AbstractBy the application of a quasi‐steady‐state time‐domain analysis approach some advance is made in the generation of non‐sinusoidal orthogonal waveforms at microwave frequencies. The main study concerns the time‐domain response of short‐circuited cascades of commensurate transmission lines. It is found that with simple prescribed pole location for the driving‐point impedance. Z11(z), on the unit circle in the z‐plane, a quasi‐steady‐state response is obtained, having a known periodicity. Furthermore, this response is automatically a member of an orthogonal set of waveforms which is uniquely associated with every choice of periodicity.
Dimensioning the low‐pass filters in pcm terminal equipment
Authors: Schultze Ernst 
Published: June 2007

AbstractIn many PCM terminal equipments both the transmission (signal sampling) and reception (interpolation of the sampled values) sides each employ a circuit in which a low‐pass filter is directly connected to a switch. In the circuits described here the energy transmission takes place during the very short interval where the switch is closed. However, the transmission is not effected by the familiar resonance transfer but by an aperiodic compensation, which is more suitable for practical use. Because of the very short time where the switch is closed as compared with the switching interval, the analysis can be greatly simplified by the use of Dirac pulses. As a result very simple formulas for the frequency characteristics are obtained which can be applied to optimize the circuit elements.
A switching‐parameter algorithm for finding multiple solutions of nonlinear resistive circuits
Authors: Chua L. O. , Ushida A. 
Published: June 2007

AbstractAn efficient algorithm for finding multiple solutions of a system of nonlinear algebraic equations is presented. This algorithm consists of solving an associated system of first order nonlinear differential equations whose independent variable may be switched from one variable to another during each integration step. The choice of the forward Euler predictor and Newton‐Raphson corrector for integrating the differential equations leads to an extremely efficient method for implementing this switching‐parameter algorithm. This approach involves only the recursive solution of an associated system of linear algebraic equations and can be easily programmed. The switching‐parameter algorithm can also be used to derive the driving‐point or transfer characteristic curve of multivalued resistive nonlinear networks.
Sensitivity evaluation and comparison for high‐order active filters
Authors: Mackay Robert , Sedra Adel S. 
Published: June 2007

AbstractThis paper presents a systematic procedure for evaluating the sensitivity of the transfer function magnitude, and hence the transmission deviation in decibels, for high‐order active filters. The procedure applies for filters having any arbitrary structure of coupled biquadratic sections. The method is illustrated by carrying out a comparative analysis on a bandpass filter realized by the Cascade, Leap‐Frog and Primary Resonator Block approaches.
New theorems in the synthesis of passive multiplexers
Authors: Youla D. C. , Winter F. 
Published: July 2007

AbstractCoupling networks that divide the frequency spectrum into separate frequency bands and also provide desired filtering are known as multiplexers. In this paper we present four new theorems concerning the synthesis‐theoretic structure of lumped passive multiplexers constructed as lossless reciprocal n‐ports. In particular we prove in Theorem 1 that any set of n – 1 admissible power gains, complementary or otherwise, can be realized by a series interconnection of n–1 appropriately chosen non‐Foster positive‐real functions. In Theorems 2–4 we establish various necessary and sufficient conditions for the realization of bounded‐real gains s21(p),…, sn1(p) given both in magnitude and phase. These conditions reveal that the general problem is one of Nevalinna‐Pick interpolation. Lastly, five worked examples are used to illustrate all facets of the theory.
Letter to the editor design of low‐sensitivity quarter‐plane recursive 2d digital filters
Authors: Palacherla Sridhar R. , Reddy P. S. , Swamy M. N. S. 
Published: July 2007

AbstractA new technique is given for designing two‐dimensional quarter‐plane recursive digital filters. These filters have low sensitivity in the passband. an implementation scheme using complex multipliers is also given for these filters.
Membrain: A cellular neural network model based on a vibrating membrane
Authors: Henseler J. , Braspenning P. J. 
Published: July 2007

AbstractThis paper introduces the Membrain model describing a neural network architecture which is similar to the architecture underlying the class of cellular neural networks (CNNs). the main difference pertains to the characteristic processing equation, which is based on a wave equation instead of a heat equation. Within the CNN framework, a cellular Membrain model may be obtained by replacing the neuron output function by a first‐order state equation. Furthermore, the network‐cloning templates are chosen such that the CNN behaves like a system of coupled harmonical oscillators. Since the energy of such a system is bounded, the piecewise linear neuron characteristic function may be chosen such that it always operates in the linear regime. Our starting point is the analytical and general solution for forced vibrations with damping. This solution applies to a Membrain neural network whose functional architecture is based on the specialized solution for a network of coupled harmonic oscillators. In particular, we present a Membrain CNN (MCNN) having a toroidal connection structure such that the natural modes of vibration of the net are translation‐invariant. Moreover, depending on the point group of the network, some rotation invariance can also be obtained. Identifying the input of such a network with the initial state of the oscillators gives rise to an output which is in essence a transversally travelling wave made up of components which are coupled harmonic neuronal oscillators; that is, the wave is a superposition of natural modes of vibration of the network. the temporal wave pattern may be transformed into a one‐dimensional temporal signal which is invariant under translation of the initial deflection pattern of the MCNN. the amplitudes of the components in the temporal signal correspond to the power spectrum of the natural vibration modes in the MCNN. Interpreting the initial deflection pattern as a grey‐level image, the temporal signal can be viewed as a modulation of a translation‐invariant ‘fingerprint’ of the image. the signal may be sampled such that the modulated ‘fingerprint’ can be classified using some of the traditional neural network models. In particular we show that (1) a self‐organizing feature map clusters correlated images and (2) a back‐propagation neural network extracts position‐invariant features.
Approximate solutions to a dynamic worst‐case tolerance analysis problem
Authors: Kolev L. V. 
Published: July 2007

AbstractA dynamic tolerance problem for linear circuits is considered. More specifically, the worst‐case analysis of the scalar step response under interval variations of the circuit parameters is treated. Approximate solutions to the dynamic tolerance analysis problem considered are suggested, two of them having the property of enclosing the exact solution of the problem.A method for determining the approximate solutions introduced is proposed. It is based on the known integral relationship between the time response and the real part of the frequency response for linear circuits on one hand and certain basic ideas and techniques from interval analysis on the other.The method reduces to evaluating some interval extension or the range of certain sums or integrals of the real part of the circuit frequency response with respect to the parameter variations.