bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved design of a multifeedback bandpass filter
Authors: Biey Mario , Premoli Amedeo 
Published: June 2007

AbstractThe multifeedback second‐order RC active filter is of considerable interest and has been studied extensively. Nevertheless, its behaviour has been in general analysed without making allowance for the non‐ideal characteristics of the embedded operational amplifier (OA).This paper presents some formulas that can be used for improving the design of such a filter. They were derived on the basis of an OA model that takes into account both input and output resistances, unity‐gain frequency, and dc‐gain. They make use of algorithms characterized by a relative simplicity and quite a good approximation. Their application makes the filter easy to tune and usable for high frequencies, while at the same time the dependence of the Q‐value on temperature variations in the operational amplifier is minimized.Two universal graphs are given in the text. They simplify the use of the new formulas in obtaining the analysis and the synthesis of the multifeedback second order filter. Experimental results that check the validity of the proposed formulas are presented.
Simplex analysis of grounded concave piecewise‐linear resistive networks
Authors: Blasi F. , Martinelli G. 
Published: June 2007

AbstractThe physical properties of the networks under consideration may be advantageously used for saving time and storage in analysing nonlinear networks. The algorithm proposed in the present paper represents an attempt in this direction. It concerns a particular class of piecewise linear resistive networks and it is based on a modification of the simplex as originally proposed by Dantzig.The algorithm requires:
The analysis of the linear network obtained by the given one by replacing the nonlinear resistances by linear ones.
The application of the modified simplex.
This second step requires a number of arithmetical operations less than that necessary for analysing a linear resistive network having a number of nodes equal to the total number of break‐points of the nonlinear resistances.
Wave‐digital cascade synthesis
Authors: Nouta R. 
Published: June 2007

AbstractThe purpose of this paper is to demonstrate the possibility of a wave‐digital cascade synthesis. Each section, reciprocal as well as non‐reciprocal, being for instance the result of a cascade synthesis based on the factorization of the transfer matrix of an analogue lossless two‐port network, is translated into a wave‐digital realization. Except for the zero‐order sections, it is shown to be sufficient that each section is cascaded with one unit‐element in order to obtain an equivalent network which can be translated into wave‐digital form. It gives some insight in the price to be paid in terms of complexity of the realization if a perfectly general transfer function is to be realized in wave‐digital form.By some examples it is shown how each structure which has been introduced can be ‘passified’ if it cannot be realized by a lossless structure.
Reactance extraction at the ports of the general reciprocal three‐port
Authors: Butterweck H. J. , Mecklenbräker W. F. G. 
Published: June 2007

AbstractThe following theorems are derived:
By means of suitable lossless, reciprocal two‐ports, any reciprocal three‐port with complex parameters can be transformed into a real three‐port.
Any desired reciprocal three‐port can be synthesized as a real three‐port with lossless, reciprocal two‐ports connected to its ports.
Simultaneous canonic synthesis of two dual impedances
Authors: Belevitch V. 
Published: June 2007

AbstractIt is proved that two dual passive impedances Z and R2/Z (R real constant) each of degree m are simultaneously realizable by a lossless reciprocal 4‐port of degree 2m closed on two constant resistances. Moreover, the lossless reciprocal 4‐port is itself realizable as a cascade of such 4‐ports of degrees 2 and 4. These are extensions of the Bott–Duffin and Fialkow‐Gerst bridges but generally contain ideal transformers. As in Fialkow‐Gerst synthesis, the only algebraic equation to be solved is Z(p) + Z(–p) = 0 but, in contrast with Fialkow‐Gerst, the realization is minimal.
Canonic realization of ladder wave digital filters
Authors: Fettweis Alfred 
Published: June 2007

AbstractWave digital filters which are derived by previously known methods from LC ladder reference filters having attenuation poles at frequencies other than zero or infinity, although being canonic in number of multipliers, are not canonic in number of delays. A simple procedure is given by means of which a canonic realization can always be derived from an originally noncanonic ladder wave digital low‐pass, high‐pass, or band‐pass filter. This procedure does not affect the values of the multiplier coefficients.
Synthesis of voltage‐transfer matrices with active RC networks embedding nullors
Authors: Stamenković Borivoje B. 
Published: June 2007

AbstractRealizability conditions for the synthesis of multiport voltage‐transfer matrices by means of RC transformerless networks embedding either balanced or grounded nullors are systematically described. The results obtained are summarized in two theorems concerning the minimum number of nullors necessary and sufficient to synthesize a given voltage‐transfer matrix.
Active inductance simulation with grounded condensers
Authors: Ahmed Muslim T. , Roy S. C. Dutta 
Published: June 2007

AbstractA technique is presented for grounding the condensers of active RC networks, which requires an additional difference amplifier stage per capacitor grounded. A generalized grounded capacitor (GC) circuit is derived for simulating a grounded inductance and it is shown that the GC‐versions of the circuits proposed by Prestcott, Rao–Venkateswaran, and Berndt–Dutta Roy form special cases of this circuit. A critical investigation is made of the sensitivity performances and the frequency limitations introduced by the operational amplifiers (OA's).
On the minimal realization of the gyrator by means of nullors and resistors
Authors: Deprettere E. 
Published: June 2007

AbstractThis paper is a second step in the proof of the conjecture that it is impossible to synthesize a gyrator by means of nullors and linear resistors with fewer than four resistors if only two nullors are permitted, or with fewer than three nullors if only two resistors are permitted. It is proved that a gyrator cannot be realized with only two nullors and two resistors. In a forthcoming paper (third step) it will be proved that a two‐nullor, three‐resistor gyrator realization cannot be obtained. The proofs are presented in such a way that at the same time a synthesis procedure for minimal nullor‐resistor networks is demonstrated.
Crystal band‐stop filters with improved spurious resonance behaviour
Authors: Matthes Helmut 
Published: June 2007

AbstractIt is a well known fact that piezoelectric band‐stop filters manifest not only the desired stopband at the fundamental resonant frequency of the crystal, but also additional stopbands at its spurious resonant frequencies. The greater the degree to which such parasitic attenuation peaks are to be suppressed, the more complex is the required circuitry.The most common crystal band‐stop filter circuits can be considered as all‐pass sections in which a capacitance is ‘disturbed’ over a narrow bandwidth by a resonant circuit. If this ‘disturbance’, possibly after conversion by means of known one‐port equivalents, consists of a high impedance series resonant circuit with the inductance Ls in parallel to the entire lattice arm R/jx1, the 3 dB bandwidth of the stopband becomes Δω0= R/Ls(1+x) in the loss‐free case. Sometimes the dual representation of the ‘disturbance’ is more appropriate. With a finite crystal Q‐factor of Qq, the insertion loss of a desired or parasitic stopband assumes the finite maximum value ǎ ∼ In (1+QqΔω0/ω∞).The width and height of the possible attenuation peaks are given in formulas, normalized curves and worked examples for seven band‐stop filter circuits of increasing complexity, each with a single crystal.
Description of electrical networks using bond graphs
Authors: Perelson Alan S. 
Published: June 2007

AbstractThe bond graph language is introduced as a means of describing the topology of an electrical network composed of one‐port and multi‐port elements in a condensed alphanumeric notation suitable for computer interfacing. Series‐parallel networks are represented in the particularly simple form of bond graph trees. Wiring operators, introduced by Penfield, can be constructed from bond graph junctions. Concepts from circuit theory can usefully be applied to nonelectrical systems which often are modeled by using multiport elements. For such systems bond graphs may provide a simpler description than conventional circuit diagrams.
Optimization of binary transversal filters with constrained sampled impulse response
Authors: Gibbs A. J. 
Published: June 2007

AbstractThe design of binary transversal filters (BTF's) suitable for shaping binary data signals is considered. It is shown that the approximation problem for such BTF's can be solved with respect to minimum mse or min—max time and/or frequency domain error, under the constraint that the impulse response exhibits a specified intersymbol interference. The BTF's considered employ only the lowpass filtering inherent in the non return‐to‐zero input data and exhibit the property that for a fixed number of taps there is an optimum BTF clock rate which minimizes the approximation error.The design of BTF's with quantized coefficients is also considered and the approximation problem solved with respect to min—max error by using mixed integer programming.
Computer‐aided analysis and design of follow‐the‐leader feedback active‐RC networks
Authors: Laker K. R. , Ghausi M. S. 
Published: June 2007

AbstractThe FLF (Follow‐the‐Leader Feedback) Active‐RC Filter is shown to be highly suited to computer‐aided optimization and design. The realization of multiple‐loop feedback networks which are both low in cost and low in sensitivity is considered. Such a design procedure is based upon the identification of those second order sections (blocks) which most critically affect sensitivity, i.e., the most critical blocks. Critical block analysis is an integral part of the sensitivity analysis, therefore, requires no additional operations.
A quasi‐steady‐state phenomenological model for a transferred‐electron oscillator
Authors: Jackson J. Russell , Rhodes J. David 
Published: June 2007

AbstractA particularly simple modelling network is postulated in order to describe the operation of a cavity‐controlled transferred‐electron oscillator. The subsequent successful agreement with experimental oscillator behaviour lends support to the well known hypothesis that the fundamental power generating mechanisms of such devices are, in many cases, operating in a highly impulsive manner.
On a relationship between howitt and T‐transformations in n‐port passive reciprocal networks
Authors: Tavsanoglu Vedat 
Published: June 2007

AbstractA new Howitt transformation is defined which is applied to the hybrid description of a newly defined augmented network obtained by extracting appropriate terminals from an n‐port passive reciprocal network. A relationship between the Howitt matrix and the matrix T, which relates the state realizations of equivalent n‐port networks, is found. For a restricted form of the matrix T, it is shown that a sufficient condition for the existence of such a relationship is that the equivalent n‐ports be reciprocal. It is also shown that this relationship always exists for equivalent n‐port RC or RL networks regardless of any restriction on the matrix T.
On the application of network theory to nonisothermal systems
Authors: Perelson Alan S. , Oster George F. 
Published: June 2007

AbstractDoubt has recently been cast on the applicability of generalized network theory for the analysis of nonisothermal systems. We briefly indicate how nonisothermal systems may be modeled from a network viewpoint choosing either entropy flow or heat flow as the through (KCL) variable. An example of a circuit containing a thermistor is considered.
On the maximal power transfer theorem for n‐ports
Authors: Flanders Harley 
Published: June 2007

AbstractThe maximal power problem is considered for several classes of terminating networks, in particular an arbitrary resistive n‐port termination, and the case of a single resistor terminating each port. A duality theorem is established that converts the problem of maximizing power to the problem of minimizing a related function. The latter problem is solved completely for arbitrary resistive terminations, and examples are given. For completeness, some previously published work is discussed.
Transfer functions for pulse forming active networks with low dominant pole q factor
Authors: Rakovich B. D. , Stojanovich V. S. 
Published: June 2007

AbstractA new class of all pole transfer functions of odd degree having the dominant pole Q factor of order of unity is described. Higher order transfer functions are derived from the third order function of a special class of Chebyshev delay approximation by increasing the multiplicity of the pair of complex poles under the constraint that the passband delay distortion remains within any prescribed maximum value. The specified delay distortion, acting as a free parameter, entails a tradeoff between the frequency and time domain characteristics of the resulting filters thus enabling a large variety of specifications to be met in practical design. These functions are primarily intended for pulse application but they can also be used advantageously in those instances where the magnitude response is of prime importance.
Cascaded lattice realization of digital filters
Authors: Mitra S. K. , Kamat P. S. , Huey D. C. 
Published: June 2007

AbstractA new algorithm is proposed to realize a digital transfer function. The final realization is in the form of cascaded lattice two‐pairs with the right‐most two‐pair being constrained such that one of its output terminals is connected directly to an input terminal. The complete realization uses m delays, 2m + 1 multipliers and 2m two‐input adders where m is the order of the transfer function. Several special cases are included, along with an example illustrating the general algorithm.
Statistical multiparameter sensitivity measure of gain and phase functions
Authors: Acar C. , Ghausi M. 
Published: June 2007

AbstractStatistical multiparameter sensitivity proposed by Rosenblum and Ghausi, for transfer function of a linear system, has been studied with regard to gain and phase sensitivities. It is shown that for small element changes a very simple relationship exists between these quantities. The integrand of these sensitivities are furthermore equivalent to the variance of magnitude and phase variations. Finally general formulas are derived which would simplify calculations for gain, phase as well as the transfer function. These formulas are helpful in optimization and comparison of various low sensitivity networks.
Digital laguerre filters
Authors: King R. E. , Paraskevopoulos P. N. 
Published: June 2007

AbstractThis paper presents the theory and a time domain synthesis procedure for a class of orthogonal digital filters. These filters are derived from discrete Laguerre polynomials and in the case of exact representation possess an infinitely long structure whilst exhibiting an infinite impulse response.In practice the desired impulse response of a filter to be synthesized is truncated in time whilst speed and economic considerations impose a constraint on its length. By the nature of these filters, very few stages usually suffice to yield excellent fidelity in most practical cases. The filters, whose cascaded stages are eminently suited to multiplexing, are inherently stable.A computer‐aided design algorithm using a Fibonacci search algorithm is presented for optimizing the practical case having finite length and span. Two examples illustrate the procedure.
Comparison of aesthetic outcomes and morbidity of nasal reconstruction with forehead flaps and free flaps
Authors: Ayhan Meltem , Gorgu Metin , Aytug Zeynep , Karantinaci Burçe , Yilmaz Elif 
Published: June 2007

AbstractThe most common etiology of nasal defects that require reconstruction is skin cancer, particularly basal cell carcinoma, the most common nasal skin cancer, as well as squamous cell carcinoma, and melanoma. Reconstruction of extensive nasal defects including nasal bone, septum, and esthetically defined units of the nose always represent with certain difficulties. Forehead flaps and free flaps can be utilized for reconstruction of extensive nasal defects. The forehead flap is a reliable and well‐established reconstructive option for management of extensive nasal defects. We aimed to compare the esthetic and functional results of forehead flaps and free flaps for reconstruction of extensive nasal defects. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Effects of tibolone on health‐related quality of life in menopausal women
Authors: Bhattacharya S.M. 
Published: June 2007

AbstractObjective: The present study assessed improvements in health‐related quality of life (HRQOL) in menopausal women using tibolone. Methods: One hundred women who underwent surgical menopause for various benign gynecological conditions were advised to take tibolone (2.5 mg) daily. The Menopause Rating Scale (MRS II) was used to assess the change in HRQOL after 3 months and 12 months of treatment. Results: Sixty‐two women returned for follow‐up after 3 months, while only 15 returned for after 12 months. Significant improvements in HRQOL were found after 3 months, and further improvements were obtained after 12 months, although at a slower rate. Among the three subscales of MRS, maximum improvement in the somatovegetative component and lesser improvements in the other two subscales were found. Conclusion: Tibolone is effective in improving the overall HRQOL of menopausal women. Somatovegetative symptoms show most improvement.
A method for determination of the isotopic composition of authigenic uranium in Baikal bottom sediments
Authors: Chebykin E.P. , Goldberg E.L. , Kulikova N.S. , Zhuchenko N.A. , Stepanova O.G. , Malopevnaya Yu.A. 
Published: June 2007

Abstract
A simple, reliable, and high-performance method has been proposed for direct determination of the isotopic composition of authigenic uranium in silica lacustrine sediments. The method is based on studying the kinetics of the selective extraction of authigenic uranium from sediments with weak solutions of ammonium hydrocarbonate followed by the ICP-MS analysis of the nuclides. To estimate the contamination of authigenic uranium by terrigenous one, the contents of 232Th and some other clastogenic elements in the extracts were measured simultaneously. The selectivity of extraction of authigenic uranium from the sediments treated with a 1% NH4HCO3 solution appeared to be no worse than 99%. The method was used to analyze the isotopic composition of authigenic uranium at several key horizons of a core dated before. The measurements directly prove that the 234U/238U values in Baikal water varied depending on climate, which contradicts the previous statements. The measured 234U/238U ratios in paleo-Baikal water match the values reconstructed from isotopic data for total uranium in the sediments on the supposition that the U/Th ratio is constant in the terrigenous part of the sediment. Direct experimental determination of total and authigenic nuclides in sediments enhances the potentiality of the method for absolute 234U-230Th dating of carbonate-barren lacustrine sediments, including those from Lake Baikal, within the intervals corresponding to the periods of glaciation, where the sediments contain a large fraction of terrigenous component. Given the fractions of terrigenous and authigenic uranium are accurately determined, we have an opportunity to study the variability of the sources of terrigenous matter and to refine the previous model for reconstructing the climate humidity in East Siberia.
Composition and conditions of formation of andalusite-kyanite-sillimanite pegmatoid segregations in metamorphic rocks of the Tsel block (Mongolian Altay)
Authors: Sukhorukov V.P. 
Published: June 2007

Abstract
Pegmatoid segregations containing three polymorphous Al2SiO5 modifications have been revealed in metamorphic rocks of the Tsel block localized in the Hercynian belt on the southern flank of Mongolian Altay. Petrographic study showed a successive substitution of polymorphs in the sequence: andalusite–kyanite–fibrolite–sillimanite. Estimated parameters of the host-rock metamorphism indicate that the mineral assemblage of pegmatoid veins formed at two successive stages of metamorphism: andalusite-sillimanite and kyanite-sillimanite. It is suggested that the transformation of Al2SiO5 from one to another polymorphous modification occurs by the ion exchange mechanism with the participation of muscovite.
Paleozoic facies megazones in the basement of the West Siberian geosyncline
Authors: Yolkin E.A. , Kontorovich A.E. , Bakharev N.K. , Belyaev S.Yu. , Varlamov A.I. , Izokh N.G. , Kanygin A.V. , Kashtanov V.A. , Kirda N.P. , Klets A.G. , Kontorovich V.A. , Krasnov V.I. , Krinin V.A. , Moiseev S.A. , Obut O.T. , Saraev S.V. , Sennikov N.V. , Tishchenko V.M. , Filippov Yu.F. , Khomenko A.V. , Khromykh V.G. 
Published: June 2007

Abstract
Facies zonation of the Paleozoic basement of West Siberian geosyncline and its surroundings is presented. Facies megazones are distinguished according to types of sedimentation. Analysis of lateral and successive sedimentary sequences shows that the available data are insufficient to map the facies distribution over the whole territory of the geosyncline for short time slices. Only the Late Devonian section is supported by data sufficient for the proposed facies zonation. Five megazones, I, II, III, IV, and V, are distinguished in the westward direction. First three megazones make up a single lateral facies succession and represent sedimentary environments on and around the Siberian continent. Megazone IV includes shallow-water volcanic and sedimentary rocks that compose the Kazakhstan continent bounded by Early and Middle Carboniferous sutures in the west and east. Megazone V comprises fold-thrust (island arc) complexes of the eastern Urals. The main events in the geologic history of the region were associated with the interaction of two major crustal masses (Siberian and East European continents) and the young Kazakhstan continent in the oceanic space called the Paleoasian ocean. Only few fragments of this space occur in the present-day framework of the territory, the greatest part being sunk in subduction zones, especially in the large zone of the Main Uralian Fault.
Production and accumulation of organic matter in pre-Mesozoic deposits occurred on continental shelves, which are most promising for Precambrian and Paleozoic oil and gas.