摘要:

AbstractThis paper discusses the numerical method of computation in the perturbation for periodic solution of piecewise‐linear autonomous system, which we can calculate up to higher‐order approximations. In many cases of autonomous equations for electrical and electronic circuits, linear and nonlinear terms can be separated leading to the equation of the form × = Ax + f(x) where = d/dt, is a small parameter. This paper considers the case where the coefficient matrix A is of the simple structure and f(x) can be represented by a practically effective piecewise‐linear function. the differential equation is transformed by the mode matrix of A, and using the discrete Fourier transform, an algorithm is constructed which determines the periodic solution up to higher‐order approximations. As the first step, a discussion is made on the relation between Jacobian matrix for Newton's method to solve the determining equation for the amplitude and phase of the zeroth‐order approximation and Jacobian matrix for the piecewise‐linear function. Then it is shown that the first‐ and the higher‐order approximation can be determined by solving the linear equation with Jacobian matrix of Newton's method in determining the zeroth‐order approximation as the coefficient matrix. It is shown also that to improve the computation time for determining the solution, a faster search of the simplex for the periodic solution is necessary, resulting in a proposal for the search method. In the proposed solution method, Newton's method does not converge when the value of the periodic solution at a time point matches a corner of the simplex. A remedy for such a

ISSN:8756-6621    

DOI:10.1002/ecja.4400661002

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

年代:1983

数据来源: WILEY

摘要:

AbstractTechniques are proposed for the design of two‐dimensional recursive filters approximating simultaneously prescribed specifications of magnitude and group delay. By treating the coefficients of the transfer function as decision variables, these approximation problems are formulated as (1) preference optimization problem and (2) optimization‐satisfaction problem, in order to obtain optimal transfer functions. In Case (1) an optimal preference solution is selected by a designer interactively from among a set of non‐inferior solutions of a 2‐object optimization problem for two performance indices of magnitude and group delay. In Case (2) the performance index for magnitude is optimized under the satisfaction condition so that the index of approximation error of group delay is always within a specified value. Finally, design examples from these two techniques ar

ISSN:8756-6621    

DOI:10.1002/ecja.4400661003

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

年代:1983

数据来源: WILEY

摘要:

AbstractMany one‐dimensional arrangements have been used with only unilateral elastic coupling for electrode arrangement of a monolithic crystal filter (MCF). However, such an arrangement has the disadvantage that disturbance occurs within the passband and asymmetry of the characteristic increases with the specific bandwidth of the filter. to remedy this, the present paper proposes an MCF with two‐dimensional electrode arrangement to allow the bridged coupling to be zero. First, confirming that the bridged coupling between nonadjacent electrodes is a main factor disturbing the passband characteristic, a method of achieving zero bridged coupling between electrodes is provided by means of two‐dimensionally arranged electrodes. A design procedure for an MCF with two‐dimensionally arranged electrodes MCF is then introduced based on the M‐coupled equivalent circuit. Furthermore, a tandem arrangement with electrodes of different length is shown to be valid for suppression of skew symmetric modes necessarily excited in the two‐dimensional arrangement. Lastly, design of a 9‐resonator, tandem crystal MCF with 0.5% specific bandwidth is presented to decrease disturbance of the in‐band ripple and asymmetry of the passband and rising characteristics. Moreover, undesired response caused by the skew symmetric mode is seen to be suppressed sufficiently without difficulty i

ISSN:8756-6621    

DOI:10.1002/ecja.4400661004

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

年代:1983

数据来源: WILEY

摘要:

AbstractQuantization error arising from roundoff and coefficient quantization presents a serious problem in realizing a digital filter with finite‐word length arithmetic. This paper proposes floating‐point realizations of digital filters that minimize quantization error. A filter synthesis problem is formulated with the relationship between round‐off error and coefficient quantization error that has recently been investigated by the authors. the formulation reveals that a combination of the minimum‐ coefficient‐sensitivity structure and the optimum order of additions leads to a realization of a digital filter with the minimum quantization noise. the proposed synthesis consists of transformations in a state space. the optimum ordering of additions is found with the assumption of the use of the successive addition that is amiable to hardware implementation. Finally, the effectiveness of the proposed method is illustrated by a

ISSN:8756-6621    

DOI:10.1002/ecja.4400661005

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper presents a new interactive multiobjective decisionmaking technique for multiobjective convex programming problems based on the weighting method. In our interactive scheme, after generating a Pareto optimal solution by the weighting method, the values of the marginal rates of substitution (MRS) assessed by the decision maker (DM) are used to update the weighting vector. As a result, the increased value of the DM's unknown utility function is sought and the local proxy preference function is updated to determine the optimal parameter value involved in the weight updating formula. In this way, the preferred solution of the DM is derived efficiently from among a Pareto optimal solution set by assessing his MRS. Furthermore, considering the imprecise nature of DM's judgments, the MRS of the DM presented in a fuzzy form are interpreted as L‐R fuzzy numbers, and the fuzzy version of the algorithm is also presented. Based on the proposed algorithm, a time‐sharing computer program is written and the interaction processes to solve a numerical example under the hypothetical DM are demonstrated together with the computer outp

ISSN:8756-6621    

DOI:10.1002/ecja.4400661006

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe spiral line shows promise for miniaturization of circuits because it has the characteristics of a strip line and has a nonlinear structure. However, analysis of this line is difficult because of nonperiodic coupling between the conductors. This paper proposes a theoretical analysis to determine the distributed parameters for a traveling‐wave mode along the line. Theoretical analysis and experimental investigation are performed for the propagation characteristics of the spiral line. the innovative feature of this method is that the series impedance and the parallel admittance due to the primary constants of the line are expressed as integrals of the current distributions. From these expressions the distributed parameters for the forward wave and the backward wave are given in a series form containing complete elliptic integrals. These distributed parameters comprise the relations between the line structure and the frequency and represent the nonperiodic coupling between conductors. Using this method, we obtain the input admittance of the spiral line with its end open or shorted. Since the results agree well with measured data, validity of the method is confirmed. It is also shown that the frequency characteristic of the distributed parameters express that of the input admittanc

ISSN:8756-6621    

DOI:10.1002/ecja.4400661007

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe Wagner coding method utilizing analog information of a received signal in the decoding of single parity check code is known to have a similar ability to that of single error correcting code. Also, it possesses a simple decoding operation. This paper proposes a concrete example of the Wagner coding method applicable to multi‐ DPSK system. Example solutions are shown to the problems such as in the parity check coding scheme which can be used in the DPSK channel, extracting scheme of the channel measurement information in the case of multi‐DPSK system, and the error correcting scheme which can be applied after the differential decoder. Further, the theoretical analyses of BER (Bit Error Rate) performance are made for the case where white Gaussian noise is offered as a signal quality degradation factor and the case where phase jitter is contained in the recovered carrier. Consequently, it is clarified that by simply adding some peripheral circuits to the conventional DPSK modulator/demodulator, the proposed scheme compares favorably with the conventional 4‐DPSK system by 2‐dB improvement in the BER performance against white Gaussian noise and also offers considerable immunity against phase jitter. the equipment is actually fabricated in the case where the proposed method is applied to a 4‐DPSK system and the effectiveness of the proposed method is confirmed through ex

ISSN:8756-6621    

DOI:10.1002/ecja.4400661008

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

年代:1983

数据来源: WILEY

摘要:

AbstractIn recent years the CSMA/CD level area network has been in wide use. However, most of the performance analyses treating stability made so far have been based on the model of a nonpersistent protocol slotted by the propagation delay, which does not represent exactly the actual system. This paper presents the delay and stability analyses of an asynchronous 1‐persistent CSMA/CD scheme with the binary exponential backoff used in the Ethernet. Since this analysis method can be applied to a nonpersistent CSMA/CD scheme or the slotted scheme under the same model, the characteristic difference between the schemes can be clarified. Further, the backoff algorithms can be analyzed under the model representing the actual system. the results of this analysis show that the 1‐persistent CSMA/CD scheme gives smaller throughput and stability than the nonpersistent scheme, and that the previous model gives results that are too optimistic.It is shown also that the binary exponential backoff is far from optimum in the throughput‐delay characteristics and the noadaptation scheme works satisfactorily under the usual condition with small propagation

ISSN:8756-6621    

DOI:10.1002/ecja.4400661009

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe field intensities near the free ends of circular and rectangular waveguides with various end profiles are measured in the microwave frequency range. It is found that there exist characteristic field profiles in front and rear of the free ends depending on the shape, slant angle and normalized frequency. the field is measured by scanning a probe antenna near the free end. the measurement process is semi‐automated with a microcomputer which controls the antenna location and processes measured data. In general, analytical treatment of the discontinuities in a dielectric waveguide is complicated. In this paper, a simplified analysis is introduced for finding approximate values of the field near the free end. From the physical requirement on the field near the free end and the phase distribution on the free end, the electromagnetic field on the free end is assumed. This field distribution is used as a source from which the near field is numerically obtained. the numerical results exhibit characteristics of the measured field except for those near the extremities. the measurement technique and the approximate analysis reported here may be applied to free ends with different shape

ISSN:8756-6621    

DOI:10.1002/ecja.4400661010

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

年代:1983

数据来源: WILEY

摘要:

AbstractA mode matching algorithm with a second‐order smoothing process is proposed for accurate and efficient analysis of H‐wave scattering from a cylindrical body with edge points in the resonant region. the smoothing process is a method for transforming the boundary condition for the wave function to a smoother one by way of an indefinite integral. Since the smoothed condition can more easily be satisfied than the original boundary condition, convergence of the approximate wave function series by modal expansion can be accelerated by the smoothing process. In H‐type scattering problems, the first‐order indefinite integral can be evaluated by the conventional smoothing process without considering the existence of edge points. However, since convergence of the mode matching solution with the smoothing process is not fast enough, accurate solutions are difficult to obtain. Hence, second‐order smoothing is used in this paper. In this case, even for H‐type problems, the algorithm has to rely on the singular smoothing technique considering the edge point. Therefore, the algorithm becomes a mode matching technique in which the conventional smoothing and singular smoothing are combined. to find the effectiveness of the method, the problem of plane wave scattering by a conducting rectangular cylinder is numerically calculated. It is found that significant improvement is achieved in accuracy of t

ISSN:8756-6621    

DOI:10.1002/ecja.4400661011

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

年代:1983

数据来源: WILEY