摘要:

AbstractThis paper proposes and describes a new cut torsional quartz resonator which is designated “TT‐Cut,” and clarifies its frequency characteristics, frequency temperature behavior, and electrical equivalent circuit parameters.First, in the analysis procedure, an equation of motion is derived from an energy method. Next, by solving the equation of motion under the boundary conditions of “free‐free bar” or “clamped‐free bar,” the frequency equations are derived as a function of thicknessz0, widthx0, and lengthy0.Furthermore, from the frequency equation a relationship of frequency constant (f.y0) versus thickness‐to‐width ratioRzx(=z0/x0) and a relationship between thickness‐to‐width ratioRzxand cut angles (ϕ, θ) where the first‐order temperature coefficient α reaches zero are derived theoretically. As a result, numerous relationships where α reaches zero are found to exist between thickness‐to‐width ratioRzxand cut angles (ϕ, θ). Especially, the second‐order temperature coefficient β has a small value of ‐1.16 × 10−8/°C2whose absolute value is approximately one‐third of the well‐known flexural mode quartz crystal resonator. The value of β then is‐compared with the measured data of ‐1.29 × 10−8/°C2, so that both results are found to agree sufficiently well.Finally, series resistanceR1and a quality factorQof a tuning‐fork‐type resonator are examined. Consequently, it is shown that a tuning‐fork‐type torsional quartz crystal resonator is obtained with a smallR1of 2.2 to 14.4 k° and a larg

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760901

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

年代:1993

数据来源: WILEY

摘要:

AbstractWith a view to developing a method enabling accurate derivation of the reflection characteristics for an oblique incidence of the surface acoustic wave (SAW) into a metallic grating which is a fundamental constituent element of an SAW device, an analysis method is formulated based on the finite‐element method (FEM). The FEM can easily be applied to an anisotropic and piezo‐electric substrate. It is possible to carry out an analysis taking into account the electrical perturbation, mechanical perturbation, and the energy storage effect by a nonradiating bulk wave at the reflection end.In this paper, from the information on the stopband computed by the FEM, the amount of reflection per reflecting strip in the reflector and the shift of the center frequency of the stopband are computed. These quantities are actually computed for gratings on a Bi12GeO20substrate and an ST‐cut quartz substrate so that the validity and usefulness of the present analysis method are pres

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760902

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper uses the fixed‐point theorem to generate a set of sufficient conditions which confine the solutions of weak nonlinear differential equations to some low‐order stable integral manifold. Furthermore, it is shown that these conditions can be weakened to a great extent if the initial values of the differential equations are confined to a bounded region.A method is proposed for finding the integral manifold in an analytic form such as a Fourier series and a new calculation algorithm which applies the Newton method and other techniques. Next, the obtained results are applied to weak nonlinear optimal regulator problems and sufficient conditions are derived for the existence of a nonlinear feedback control law which meets the necessary conditions for optimality. Simulations using the algorithm exhibited favorable resu

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760903

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn general, inevitably the particular structure called generalized upper bounding (GUB) occurs when transforming the reliability optimization problem such as optimal unit selection and redundant allocation. These are formulated as the nonlinear integer programming problem and transformed to the 0‐1 linear programming problem.Recently, a method for solving the fuzzy multi‐objective 0‐1 linear programming (0‐1 FMOLP) problem which extends the efficient method considering the GUB structure to the more general MOLP problem is proposed. Also, the method is extended to deal with the fuzziness of the goal value toward the objective function. However, this method is not considered for the break‐down of the fault‐detecting and switching (FDS) device; thus, it does not sufficiently cope with the real world's reliability optimization problem.From these viewpoints, an algorithm is proposed for solving the optimal redundant unit selection problem that optimizes the system reliability with imperfect FDS device by fuzzy 0–1 MOLP. The method proposed here considers the fuzziness of the decisionmaker (DM) toward the goal value of each objective function by introducing the fuzzy goal. Further, this method enables the DM to determine the most satisfactory solution to the attainment of each goal value of the objective function and constraint and can cope with the realistic optimal design of the system reliabi

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760904

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe requirements specification and definition is one of the important and difficult tasks in the design and implementation of systems which realize various user requests.This paper proposes a knowledge‐based requirements specification and definition method for computer communication system design. In the proposed method, a framework for representing and utilizing various design knowledge of the requirements specification and definition is introduced based on a knowledge‐based design methodology for a computer communication system. According to the proposed method, the requirements specifications of logical functions of a computer communication system can be derived systematically from the users' requests and also represented in the formal descriptions called knowledge models of the requirements definition t

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760905

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper considers the construction of two‐dimensional (2‐D) adaptive state‐space filters using the least mean squares (LMS) method. The approach is based on the Roesser local state‐space model. First, the relation between the coefficient sensitivities and the intermediate transfer functions is investigated. Then, after introducing new systems for generating the gradient vectors, an adaptive algorithm is developed using the LMS method.Next, a 2‐D adaptive state‐space filter with separable denominator is introduced to reduce the amount of computation in the adaptive process. Finally, a numerical example is given in which the 2‐D adaptive state‐space filters are used to design 2‐D digital filters in t

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760906

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper studies the synchronization phenomenon of frequency and phase of two coupled limit cycle oscillators. This problem is fundamental for many subsystems coupled to each other to behave autonomously.A nonlinear coupled system becomes the gradient system if its coupling factors are chosen appropriately and then a potential function can be determined. Moreover, conditions for the potential function to have the minimum point are investigated and, from this condition, the synchronization conditions of frequency and phase of two coupled oscillators are studied. It is shown that the simulation results agree quite well with the theoretical ones.

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760907

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

年代:1993

数据来源: WILEY

摘要:

AbstractWith the rapid progress of VLSI microfabrication technology, the functional cell library must be updated frequently. Then it is important to develop a functional cell generation technique. For this purpose, the study of technique is considered interesting, which represents the layout pattern efficiently and independently of the process technology, using a language.This paper discusses the layout language based on the general‐purpose C language and the processing system. The layout pattern is described using C language and newly defined functions for layout description. Then the layout data are generated automatically from the description.First, the assumed layout pattern structure is considered. Then the proposed layout description technique, as well as the realization of the processing system, are discussed. Finally, the processing system actually is constructed and it is demonstrated that the layout pattern is generated automatically from the layout descriptio

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760908

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper considers digital filters with hyper‐complex coefficients. Filters of this type can reduce the order of filters to one‐fourth the one with real coefficients. It is reported that the first‐order digital filter with hypercomplex coefficients can realize the fourth‐order digital filter with real coefficients which can be expressed by a second‐order all‐pass filter with complex coefficients.This paper considers also generalization including the foregoing special case and shows that the first‐order digital filter with hypercomplex coefficients can realize an arbitrary‐order digital filter with real coefficients less than 4.Arbitrary higher‐order digital filter with real coefficients can be realized by parallel connection or cascade connection of first‐order digital filters with hypercomplex coefficients. This paper considers the following three different realizations: (a) realization by parallel connection; (b) realization by cascade connection of real part; and (c) realization by cascade connection. We find that case (b) is the most low sensitive. Finally, stability criteria of hypercomplex digital filters of first

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760909

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe repetition frequency and the maximum disparity in stereoscopic vision where depth movement is perceived are determined using a static random dot stereogram (SRDS). Furthermore, the temporal frequency characteristics of the maximum fusible disparity are determined using a dynamic random dot stereogram (DRDS). The results show that in both cases, as the frequency of depth movement increases, the maximum fusible disparity decreases. For sine waves above 15 Hz and square waves above 7.5 Hz, binocular fusion is not possible when the target is the SRDS. For both sine and square waves above 7.5 Hz, binocular fusion is not possible when the target is the DRDS. In both cases, binocular fusion is only possible at lower frequencies. It is clear that compared to SRDS, the maximum fusible disparity is larger for DRDS when the center of motion is set on the plane of the screen and becomes smaller when the center of depth motion is shifted off the screen as the shift of the center of motion increases or fusion becomes impossible in the high frequency range.

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760910

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

年代:1993

数据来源: WILEY