摘要:

AbstractBesides switched‐capacitor (SC) filters developed for high volume production, e.g. the PCM‐codec lowpass filter, numerous low volume applications exist in the area of solid‐state filtering. to open up this application field for SC filters, a novel wave‐SC filter structure is presented. the filter design using this concept requires only moderate design and layout skills since only a limited library of highly modular building blocks is required. It is also suitable for analogue gate array applications. As will be shown, the wave equations which are known from the theory of wave digital filters can be realized using stray‐insensitive SC integrators and SC amplifiers only. Exemplary designs of a lowpass, a highpass, and a bandpass filter will be carried out with the building blocks presented. the theoretical results are verified by measurements at the breadboarded lowpa

ISSN:0098-9886    

DOI:10.1002/cta.4490120202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper discusses a method of designing quadrantally symmetric cascaded two‐dimensional (2‐D) digital recursive filters by subjecting a one variable approximating function to successive transformations. the needed approximation is done in the one variable domain rather than in the 2‐D domain, hence leading to a large reduction of computational labour. Using cepstral techniques each denominator polynomial is spectrally factorized into recursible non‐symmetric half plane components. A significant feature of the method is in decoupling the problems of approximation and stability. Consequently spectral factorization needs to be performed only once for each denominator polynomial. Effects of truncation on filter stability are minimized by ensuring rapid convergence of cepstra. the choice of an adequate DFT size in cepstral computations is shown to be an important consideration for many problems associated with spectral decomposition. Attempts are also made to stabilize the unstable transfer function using an existing 2‐D discrete Hilbert transform method. Considerable distortion in magnitude characteristics is shown to result on stabilization. Finally the method is illustrated by two

ISSN:0098-9886    

DOI:10.1002/cta.4490120203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper deals with multiple‐fault diagnosis for linear analogue circuits. the proposed approach is based on multifrequency measurements of some voltage (transfer function) at the accessible output port and can be used for multiple‐fault location. It uses certain algebraic invariant properties of the transfer function with respect to the set of faulty elements. Computationally this approach reduces checking the problem of multiple‐fault diagnosis to one of the existence or non‐existence of a common solution of two systems of linear equations; this amounts to the finding of the rank of a matrix. These linear equations are derived via symbolic representation of the measured voltage (transfer function) accessible for measurements. A numerical example of the application of such an approach i

ISSN:0098-9886    

DOI:10.1002/cta.4490120204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe interpolation problem forn‐dimensional positive real functions is formulated in two different settings: with interpolation knots either contained on the distinguished boundary of the Cartesian product of open right half planes or in thisn‐dimensional ‘open right half plane’. A complete solution of the first problem is given. Necessary conditions of existence of a solution of the second problem are proved and the well known Nevanlinna‐Pick algorithm is generalized so that construction of interpolatingn‐dimensional positive real functions becomes possible at least in case when the interpolation knots are real vectors. Examples illustrate the suggested methods, show the complexity and significance of the problem and methods under discussion.Interpolation in special classes of functions has for some time been an important problem in mathematics. General schemes of solution in linear functional spaces with orthogonality are well known. For classes of functions which do not satisfy the axioms of a linear space special methods have been studied in detail, because they are closely connected to other important parts of mathematics such as approximation theory, numerical analysis and the theory of moments. Considerable efforts have been put into interpolation in the complex domain with functions analytic in the unit disc and with positive real functions. the significance of interpolation procedures in the class of one‐variable positive real functions in network theory, e.g. in broadband matching and approximation problems has been recognized in References 1‐3. an excellent survey paper has recently been devoted to these problems;4in this paper some new ideas for the use of interpolation in system theory were outlined. the growing interest in multivariable network theory calls for generalizations of interpolation procedures to multivariable cases. Many of the one‐variable applications can easily be extended to the multivariable case and it is hoped that in passive network theory and in problems ofn‐dimensional digital systems the solution of the interpolation problem will contribute to the difficult synthesis problems in the multivariable theory.In this paper conditions for the existence of multivariable positive real interpolating functions will be investigated and some procedures for the construction of such function

ISSN:0098-9886    

DOI:10.1002/cta.4490120205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractBased on the two‐port describing function characterization, frequency domain stability conditions are derived for non‐linear two‐port amplifiers. the conditions are applied to the case of a turned transistor amplifier with saturated class‐C type transfer characteristic. the theoretical considerations and the experimental results are in close ag

ISSN:0098-9886    

DOI:10.1002/cta.4490120206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe problem of the existence and uniqueness of solutions for a certain class of non‐linear networks, including locally active elements and controlled sources, is considered in the paper. the conditions under which the input characteristics of the network are monotonically increasing are also analysed. Two theorems relating to the problem in question, containing some results in terms of the network topology, are formulate

ISSN:0098-9886    

DOI:10.1002/cta.4490120207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractEven simple circuits containing only one op amp and linear resistors can have multiple d.c. operating points. Using a realisticnon‐lineard.c. op‐amp model which includes the saturation characteristics, this paper gives thenecessary and sufficient conditionsfor an arbitrary op‐amp circuit (containing op amps, linear resistors, strictly‐increasing non‐linear resistors and independent sources) to have auniquesolution for all values of circuit parameters. These conditions are remarkable because they are couched strictly intopologicalterms. For many op‐amp circuits (e.g. those containing only one op amp), the necessary and sufficient conditions can be checkedby

ISSN:0098-9886    

DOI:10.1002/cta.4490120208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0098-9886    

DOI:10.1002/cta.4490120209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0098-9886    

DOI:10.1002/cta.4490120201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY