摘要:

AbstractA neuron can be considered as a threshold element with refractory period. In order to arrive at a generalized treatment of several neuron models proposed in the past, this paper considers a certain type of threshold element network model which has, in addition to exponential decay of refractoriness with time, the effect of past excitations included in the exponent. The periodic behavior of such a network is analyzed and the existence condition for arbitrarily assumed periodic sequence and its generation rule are derived. The procedure is closely related to the continued fraction expansion of a rational number and the sequence is uniquely determined from the network dynamics. The entire set of periodic sequences produced by a network can be derived by the proposed procedure. Lastly, the relation between the proposed network model and the analog neuron model is discussed.

ISSN:8756-6621    

DOI:10.1002/ecja.4410650202

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

年代:1982

数据来源: WILEY

摘要:

AbstractThis paper presents a basic discussion for all possible topological minimal realizations of the generalized immittance converter (GIC), which is one of the most important functional two‐ports. In other words, a systematic derivation is presented for the lower bounds for the number of necessary elements in the topological realization of a GIC using nullors and positive resistors, as well as for all of the two‐graphs (voltage and current graphs) for the minimal realization of a GIC from the port characteristics, based on the necessary and sufficient condition for the port‐parameter of anN‐port to be topologically non‐zero. As is anticipated from the general expressions for the port‐parameters, the network structure essentially depends on whether or not the gain of the GIC has unit magnitude. Consequently, the discussion is divided into the cases where the gain of the GIC is of unit magnitude and where it is not. Using the result of this paper, all minimal realizations for GIC, including the newly derived ones, can be derived systematically and ea

ISSN:8756-6621    

DOI:10.1002/ecja.4410650203

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

年代:1982

数据来源: WILEY

摘要:

AbstractA report was previously made on problems, for given port characteristics of a functional resistive two‐port, to determine the lower bound for the number of elements needed in the topological realization of the characteristics with nullors and resistors, or to determine the voltage and current graphs GVand Gi. The algorithm to determine the two‐port in the nullor model from Gvand Gihas also been published for simple cases [7, 8]. This paper describes, for given Gvand Gifor an Nth order real square matrix, a generalized algorithm to determine the nullor model N‐port with specified port characteristics. The algorithm is applied to the topologically minimal realization of the generalized immittance converter (GIC) to determine all possible minimal GIC realizations. The algorithm forms a basis for the proposed topological network synthesis, which is a kind of structured system synthesis. Various applications of the idea as well as the determination of Gvand Gifrom an Nth order real square matrix are also disc

ISSN:8756-6621    

DOI:10.1002/ecja.4410650204

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

年代:1982

数据来源: WILEY

摘要:

AbstractRecent advances in the technology of microelectronics have changed the design rule for printed wiring boards, allowing the number of wiring tracks between consecutive pins of an ordinary dual in line package (DIP) to be two or more. When the wiring density augments to that extent, conventional routers are confronted with various difficulties.To cope with this situation, the single‐row router which has topological fluidity can be employed in conjunction with the line‐search router. We have already developed a new routing system constructed of a line‐search router combined with a single‐row router and of a maze‐running router. However in each routing process there are many parameters, the combination of whose values have much influence on the wiring performance of the whole system.In this paper we outline this routing system, describe some experimental results in order to determine values of these parameters, and show that the analysis of implemented results suggests high performance for high density printed circuit board

ISSN:8756-6621    

DOI:10.1002/ecja.4410650205

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

年代:1982

数据来源: WILEY

摘要:

AbstractSwitched‐capacitor filter (SCF) design methods reported so far fall into one of the following categories: design from the s‐do‐main, in which a filter is synthesized based on a direct approximation to the s‐transfer function; or design from the z‐domain, in which the system is regarded as being discrete and z‐transfer function is used. This paper proposes a new method of SCF synthesis based on an approximate s‐z conversion, starting from a given frequency characteristic. Characteristics of equivalent capacitors and SC integrators are expressed in a variable p(z). The desired characteristic F(s) is then approximated by the least‐square method with a rational function of p, FC(p).An SCF is constructed from FC(p) using the element substitution method in active FC filter networks. Previously proposed methods of synthesis from the s‐domain based on linear approximation or bilinear transformation result in large substitution errors, especially when relatively low sampling frequency is used. The present method minimizes substitution errors and extends signal bandwidth close to its

ISSN:8756-6621    

DOI:10.1002/ecja.4410650206

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

年代:1982

数据来源: WILEY

摘要:

AbstractWe have studied a standard launching filter, which can realize a field distribution close to the steady‐state modal field in the optical‐loss measurement of graded fibers and can be used as a reference fiber in the splicing‐loss measurement by a back‐scatter method. By using a small‐core fiber with the core radius 30 ‐ 40 μm, which is smaller than that of the fiber to be measured (50 μm), we realized a field distribution close to the steady‐state modal field. It was found that the variation of the excited modal distribution due to a difference in the radiation pattern of the optical source can be reduced by inserting a graded fiber and a step‐index fiber between the source and the small‐core fiber. When a fiber with a standard backscattering coefficient is placed between a small‐core fiber and the fiber to be tested, it becomes possible to apply the splicing‐loss measurement based on the backscattering technique. The optical loss measured by a standard fiber designed for the 1.3‐μm wavelength agreed with the value at the steady‐state modal distribution within ±0.05 dB/km. It was found that the optical loss at 0.85 μm can be measured within ±0.1 dB/km by using the same standard fiber. From these studies, it now becomes possible to measure the optical loss and the sp

ISSN:8756-6621    

DOI:10.1002/ecja.4410650207

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

年代:1982

数据来源: WILEY

摘要:

AbstractIn optical fiber splicing, the fusion technique using gas discharge heating is considered a practical method from the viewpoints of operation and reliability. The fusion by which the splicing is made after pre‐shaping by a gas discharge on the optical fiber ends, has excellent features of low loss and stable splices. However, the splicing mechanism and the optimum splicing condition have not yet been analyzed sufficiently. This paper studies splicing conditions such as the pre‐fusion time, optical fiber stuffing length and shape‐up time of the optical fiber splicing by pre‐fusion method from the viewpoint of splicing shape, splice loss and core distortion. The optimum conditions for realizing a low‐loss splice are then determined. As a result, it is clarified that although the pre‐fusion method essentially becomes a mechanism for increasing the splice loss due to core distortion caused by pre‐fusion, there exists an optimum stuffing length for minimizing its effect. It is also shown that for performing stable, low‐loss splicing (even in the case where the condition of the optical fiber end is bad), it is proper to have a pre‐fusion of 0.3 ∼ 0.4 second. A foundation for the design of the splicing ap

ISSN:8756-6621    

DOI:10.1002/ecja.4410650208

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

年代:1982

数据来源: WILEY

摘要:

AbstractThis paper describes a switching scheme for satellite communication systems employing both lightly loaded (bursty) and heavily loaded terminals. In the proposed scheme, the frame is partitioned into two types of subframes for servicing the two types of terminals. The subframe for heavily loaded terminals consists of the reservation channel and the message channel. The subframe for lightly loaded terminals employs a slotted ALOHA scheme for the transmission of packets. The heavily loaded terminals make reservation through reservation‐channel using reservation packet, and send messages by using time slots of the message‐channel. Analysis is performed to derive the mean packet transmission delay for the lightly loaded terminals and the mean message transmission delay for the heavily loaded terminals. It is shown that if one type of delay is controlled then there exists an optimum frame length that minimizes the other type of delay. It is also shown that the transmission delay of the proposed scheme is shorter than those of the conventional TDMA and the slotted ALOHA sche

ISSN:8756-6621    

DOI:10.1002/ecja.4410650209

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

年代:1982

数据来源: WILEY

摘要:

AbstractA voltage controlled oscillator using a SAW resonator does not need multiplication and tuning in the 100 MHz ‐ UHF band so that miniaturization and circuit simplification can be achieved. It also has the feature that less power is dissipated than with a SAW delay line. In this paper the SAW resonator voltage‐controlled oscillator (SAWR‐VCO) is used as a modulator suitable for a phase locked loop (PLL) and its modulation sensitivity and distortion are analyzed. Tests confirm the analysis of SAWR‐VCO performance. Finally a PLL modulator structure and the modulator circuit for use in an automotive mobile telephone unit is de

ISSN:8756-6621    

DOI:10.1002/ecja.4410650210

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

年代:1982

数据来源: WILEY

摘要:

AbstractFuture telecommunication networks will be digitalized and widebanded. The crosstalk between telecommunication lines will be a problem when bilateral signals are transmitted concurrently through a balanced pair cable. A study to suppress this crosstalk is being conducted on a balanced multipair cable with internal shielding for proper units, hereinafter referred to as a shielded balanced pair cable. Theoretical equations are needed to represent the crosstalk attenuation characteristics between shielded balanced pairs for the purpose of designing shield structures for such cable. Hitherto, no equation has been derived pertaining to the amount of crosstalk attenuation between shielded pairs applicable to the design of shield structures.In this paper, shielded balanced pair cables are divided largely into unit‐shielded types and screen‐shielded types. Theoretical equations are derived pertaining to the amount of crosstalk between shielded balanced pairs with consideration of both direct and indirect crosstalk paths. The correspondence to measurements permits design of shield structures by confirming the adequacy of the theoretical equations.In addition, it is established that both direct and indirect crosstalk have dominant frequency ranges considering these frequency characteristics. The electrostatic unbalanced capacitance is also presented for wire shielding within a required amount of crosstalk attenuat

ISSN:8756-6621    

DOI:10.1002/ecja.4410650211

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

年代:1982

数据来源: WILEY