摘要:

AbstractNonlinear systems contain a phenomenon called bifurcation. In the phenomenon, a small change of the parameter of the system can produce a qualitative change in the system behavior. On the other hand, random behavior in the deterministic system is attracting attention. This behavior is called chaos and is becoming a major problem in engineering. This paper discusses first the bifurcation and chaos in the sampled‐data control system with differentiable nonlinear elements. It is shown theoretically that the fold bifurcation does not occur when the sampling period is changed. Then various kinds of bifurcations are determined analytically for the second‐order system with cubic‐type nonlinear characteristics. It is verified by numerical experiment that the period‐doubling bifurcation can occur. Finally, it is shown that the shape of the strange attractor can change with the sampling period. the result of this study will provide a guide for the determination of the sampling

ISSN:8756-6621    

DOI:10.1002/ecja.4400660402

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

年代:1983

数据来源: WILEY

摘要:

AbstractA method using the averaged potential is proposed for analyzing the oscillation in a multimode negative resistance oscillator. the averaging method is applied to the mixed potential defined by Brayton and Moser and a function called the averaged potential is introduced that expresses the average of the loss (dissipation) of the system. the averaged equations derived by applying the averaging method to the network equations can be expressed as the gradient system of the averaged potential. Hence, stable oscillation corresponds to a minimum of the averaged potential. the analysis of the system is reduced to constructing the averaged potential and to finding the minima. the physical meaning is clarified for the phenomenon of minimal loss of the system in a stable oscillation system. General rules of initiation of nonresonant multimode oscillations are derived because the averaged potential becomes a quadratic form when the chracteristic of an active device is expressed in terms of a polynomial of order three.

ISSN:8756-6621    

DOI:10.1002/ecja.4400660403

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper proposes new methods of burst error correction for block interleaved error‐correcting codes. First, a probabilistic method of a single burst error correction, using syndrome correlation of subcodes which constitute the interleaved code, is presented. With this method, the high capability of correcting burst errors potentially owned by the interleaved codes is realized with less decoding delay. Second, by generalizing the above method, a probabilistic method of multiple (m‐fold) burst error correction is presented. With this method, after estimating the burst error positions using syndrome correlation of subcodes which are interleaved m‐fold burst error detecting codes, erasure errors are corrected in each subcode and m‐fold burst errors are corrected successfully. the code constructed by interleaving m‐fold burst error‐detecting codes is shown to be superior to the Reed‐Solomon code for 2‐fold burst error correction with respect to both error correction capability and decoding delay. the performances of these methods (single burst error correction method and multiple burst error correction method) are analyzed by computer simulation and their effectivene

ISSN:8756-6621    

DOI:10.1002/ecja.4400660404

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

年代:1983

数据来源: WILEY

摘要:

AbstractWiener analysis of nonlinear systems is now applied to the identification and description of input‐output relationships of systems in engineering and biology. However, since we do not know the relationships between the traditional representations of systems such as a block diagram and a differential equation, and Wiener kernel functions which characterize systems in this analysis, it is difficult to interpret the description of an input‐output relationship by Wiener kernels. Thus a table has been proposed which relates those representations. In this paper, noting that the output of a system represented by Ito stochastic differential equations (which forms one of the nonlinear systems) is a diffusion process, we derive a formula to obtain Wiener kernels by using a transition probability density functions. From the formula we obtain Wiener kernels for a few examples of the differential equation. Also, we discuss the possibility of investigating the input‐output relationships of some feedback sy

ISSN:8756-6621    

DOI:10.1002/ecja.4400660405

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

年代:1983

数据来源: WILEY

摘要:

AbstractA rerouting scheme is described, which is incorporated into an existing automatic routing system for single‐layer printed wiring boards and hybrid integrated circuits. This scheme is to strip and reroute portions of the current wire patterns so that not only incomplete from‐tos can be interconnected by means of getting rid of blockages, but those conductor paths so far determined which form unnecessarily long detours can be improved. Several implementation results are also sh

ISSN:8756-6621    

DOI:10.1002/ecja.4400660406

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

年代:1983

数据来源: WILEY

摘要:

AbstractFor economical construction of general microwave communication channels passive repeaters are used. Effective improvement in avoiding momentary interruptions cannot be expected unless measures are adopted to prevent fading at passive repeaters and space diversity is employed at the antenna side.The radiation field of an aperture type antenna is represented by the product of the amplitude distribution and the phase distribution of the field at the aperture. Amplitude distribution has been the main area considered in analyses to date. This paper discusses a method for controlling the phase distribution and shows that this method is best suited to prevent fading. the method modifies the shape of a conventional flat reflector excited by plane waves into a polygonal cylinder which inscribes a shallow parabolic cylinder, so that a near‐axis directional beam is formed in even the direction of the first null point of the reflected waves. the level at the first null point of a polygonal cylindrical reflector designed to keep the gain reduction directly on the axis below about 1 dB agrees well with the predicted mean field intensity due to fading at a receiving point. the use of a polygonal cylinder reflector is economical and prevents momentary interruptions due to fading so that the communication channels remain stable and possess high quality with improved reliabilit

ISSN:8756-6621    

DOI:10.1002/ecja.4400660407

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

年代:1983

数据来源: WILEY

摘要:

AbstractIt has been known that error rates as well as spectrum performances can be improved by adoption of transit‐ and receive‐baseband filters for digital FM/discriminator detection schemes. the present paper studies these modulation/demodulation schemes with baseband filters for Nyquist (NYQ) and class I, II partial‐response (PR) transmission. Error rates are analyzed theoretically with and without consideration of the intersymbol interference due to a bandpass filter. Two methods are obtained: in the former case, a generally applicable calculation method which requires the assumption of a symbol sequence, and in the latter case, a simpler calculation method than that before.The calculated results agreed well with the computer simulated results. In comparison with 2, 4 and 8 level NYQ, 3 and 7 level class I PR and 5 level class II PR, higher performance is given by the method in the order of 7 level class I PR, 8 and 4 level NYQ for narrow band transmi

ISSN:8756-6621    

DOI:10.1002/ecja.4400660408

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper clarifies the design method and radiation characteristic of a satellite antenna (which covers Japanese territory by multiple beams) and a shaped beam simultaneously. This antenna is an offset paraboloidal reflector antenna fed by multiple horns. the main features are the realization of a multiple beam which covers 4‐divided Japanese territory and a shaped beam which is adapted to the form of Japanese territory by one reflector, and the addition of an RF sensor which enables high‐precision pointing direction control.First, a multiple beam antenna and a shaped beam antenna covering the same service area are discussed. It is shown that the optimum reflector parameters are different and a combined multiple/shaped beam antenna covering most of the service area with high gain can be constructed. Next, the RF sensor needed for antenna pointing direction detection is considered. It is shown that the RF sensor can be admitted into the horn cluster for some positions of a beacon station. Finally, from the measurement at the fabricated antenna it is ensured that the increase in primary radiator loss is small due to the multiple/shaped beam sharing and the antenna gain agrees well with designed value. It is clarified that the practical configuration of multiple/shaped beam antenna can actually be reali

ISSN:8756-6621    

DOI:10.1002/ecja.4400660409

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper proposes a Priority‐based Packet Reservation Demand Assignment TDMA (PR‐TDMA) system by dividing the TDMA channels into two kinds of channels. They are fixed assigned channels and demand assigned channels; in this way it is possible to integrate various communication services such as interactive data, voice, video, file, etc. in satellite packet communications. We have classified the user traffic into three classes. the fixed assigned TDMA channels are used for interactive data and reservation information, while the demand assigned channels are used for bursty file and video, and real time voice transmission by reserving demand assigned channels. the coexistence of two forms of traffic, traffic requiring high speed transmission capacity and traffic requiring time transparency, is made possible by reserving the channels on the basis of slot length and repeated frame period. an access algorithm and an approximate analytic model are described for the evaluation of channel utilization and message delay. Theoretical results are examined by computer simulation and design trade‐offs are consi

ISSN:8756-6621    

DOI:10.1002/ecja.4400660410

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe so‐called “drift” of a charged particle annexed to the movement along the magnetic flux lines in a curved coil could be compensated by bending the coil in a letter “S” form (S‐type coil) or by superposing vertically the electrostatic fields to the magnetic fields.For an S‐type coil, when an electron beam accelerated at 2.5 kV was injected into the center of the coil, the focused beam was extracted through the center of the exit plane of the coil. Here, the height of the coil, the horizontal distance between the incident and the exit planes, and the strength of the magnetic fields were 225 mm, 60 mm, and 6.1 × 10−3T, respectively. In this case, since the exit plane could be moved freely parallel to the incident plane, the focused beam was extracted according to the movement of the exit plane of the coil.Further, when the electric fields produced by a cylindrical static deflector were superimposed vertically to the magnetic fields in the coil with bending angle 90°, a focused beam without any drift was also obtained from the center of the exit plane.Therefore, this focusing deflection system will be available to transport the charged beam or to analyze the energy distribution of

ISSN:8756-6621    

DOI:10.1002/ecja.4400660411

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

年代:1983

数据来源: WILEY