摘要:

AbstractThis paper considers the set of waveforms for which the weighted power‐of‐p(1

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760601

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper presents a least‐squares adaptive equalizer that provides good performance even in an ill‐conditioned environment where the channel distortion is rather severe. Using complex‐valued tap coefficients and halving the order of the transversal equalizer result in a substantial reduction in the condition number of the input correlation matrix composed of input signals to the equalizer. The input and output signals for the equalizer are transformed into analytic signals. Then a sampling operation of decimation by a factor of two is performed. Adaptive filtering is performed based on complex arithmetic. Compared with commonly used real‐valued adaptive equalizers, accuracy of the estimation of tap coefficients is improved substantially and the computational burden per time is reduced. Computer simulations will show the effectiveness of the proposed adaptive eq

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760602

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe Hopfield neural network is considered to be promising as a means to solve the paired association problem, which is to recall complete information from incomplete information by realizing the highly parallel system. However, the neural network has problems in that the already memorized basic memory (complete information) which is the closest to the input, may not be recalled or a solution other than the basic memory may be recalled. When, for example, the neural network is weighted using the sum of the autocorrelation matrices, solutions other than the basic memory are produced as the outputs for more than half of the possible input incomplete information.This paper aims to remedy these problems and proposes a new weighting method for the Hopfield neural network. In the proposed method, the evaluation function for the weighting is defined and the weights are determined so that the evaluation function is optimized.To determine the weights by the proposed method, a fairly complex algorithm must be executed, compared to the calculation of the sum of the autocorrelation matrices. However, the weighting process is required only once in the design of the neural network and the neural network designed by this method is expected to exhibit a better performance than the traditional network.

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760603

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper defines anew the maximum two‐route flow as a measure to represent the relation between two vertices in the flow network. The maximum two‐route flow corresponds to the maximum number of communication channels that are composed of two‐route paths between two terminals in a communication network. The ℱ‐rings that can be composed simultaneously, containing the considered two vertices, is defined as the maximum two‐route flow between those two vertices.It is shown in this paper that a theorem exists for the maximum two‐route flow similar to the max‐flow min‐cut theorem for

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760604

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

年代:1993

数据来源: WILEY

摘要:

AbstractUntil now, no code has been reported which can algebraically correct errors consisting in bit deletions or insertions (synchronization errors) and errors by bit inversion (inversion errors) when they occur simultaneously. This paper proposes a code that can algebraically correct simultaneously occurring synchronization and inversion errors as long as they occur within the range of a single byte. The proposed code is practical, involving very simple operations, and can correct synchronization and inversion errors in an information sequence ofkbytes, where 1 byte consists ofqbits, when the errors occur within a single byte. The redundancy and effectiveness of the code also are discussed.

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760605

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe weight distribution of a code usually is investigated on the basis of Hamming weight. For such non‐binary codes as Reed‐Solomon (RS) codes, therefore, all nonzero components of codewords are regarded as identical. To describe the structure of nonbinary codes in more detail, each nonzero component should be distinguished from the other. This requirement can be met by the complete weight distribution (CWD).Recently, Blake and Kith and the present authors derived independently the CWD for a special class of RS codes. However, the derivation of the CWD for general RS codes remains a difficult problem. This paper discusses the problem of obtaining the CWD for general RS codes. To make this process easier, three unique sets of codewords which should be examined are defined first. Then it is shown that the CWD can be derived from such unique sets of codewords. Finally, a relationship between the CWD for RS code of dimensionkand that of dimensionk+ 1 is conside

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760606

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

年代:1993

数据来源: WILEY

摘要:

AbstractThere have been a large number of approaches to the optimal value problem but only a few from the information‐theoretical viewpoint. In particular, no measure to represent the easiness in solving the optimal value problem has been presented.From such a viewpoint, this paper represents the object function which is the object of the optimization in the form of the Boltzmann distribution and the properties of the object function are represented quantitatively using the entropyS(pβ) ≡ − Σpβ(x)logpβ(x) of the Boltzmann distribution.It is noted that the optimal solution is difficult to obtain in the actual computation for the optimization problem taking discrete values. For this problem, a measure is introduced for the easiness of the problem (object function) to be optimized, apart from the algorithm to arrive at the optimal

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760607

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe coupled‐mode theory is extremely useful for analysis of such periodic structures as grating reflector, resonator, and unidirectional transducer making use of electrode reflection as important constituent elements for the SAW devices. Here, the coupled‐mode equations describing the transduction characteristics of the inter‐digital electrode transducer (IDT) are derived directly by the perturbation theory. In addition, the parameters for the coupled‐mode equations are presented for quartz, LiTaO3and LiNbO3substrates.Next, based on the coupled‐mode equations, the relationship among the quantities of the electrical port and two acoustic ports of the IDT is derived. The entire periodic structure was represented by a simple distributed equivalent circuit. The equivalent circuit analysis method is described for the analysis of the device characteristics. To show the usefulness of the present method, a backward‐wave type trapped‐energy SAW resonator and the resonator coupled filter

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760608

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

年代:1993

数据来源: WILEY

摘要:

AbstractTo realize surface acoustic wave (SAW) filters with low‐loss and wide bandwidth for mobile communications, a floating‐electrode‐type unidirectional transducer (FEUDT) using internal reflection is discussed. The proposed structure for FEUDT has an advantage of manufacturability and also for high‐frequency performance exhibiting a second harmonic operation better than a fundamental mode.This paper describes both a theoretical and experimental result. A leaky surface acoustic wave (LSAW) of SH‐wave type using 41 °YX LiNbO3substrate, the velocity of which is much faster than that for a usual Rayleigh wave and has a largeK2is used. A second harmonic FEUDT suitable for this wave is obtained theoretically by using the Green function method. The result is in good agreement with experiment.An SH‐type LSAW is more sensitive to a surface boundary condition of a substrate compared to the usual Rayleigh wave and thus the boundary condition for a low‐loss filter is very important. This is discussed both theoretically and experimentally. It is found that an open grating is the best for a propagation path if one considers the mode conversion of LSAW excited by a transducer. A prototype filter has been fabricated. The insertion losses of 2.6 dB and 2.8 dB at the center frequency of 360 and 700 MHz, respectively, are obtaine

ISSN:1042-0967    

DOI:10.1002/ecjc.4430760609

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

年代:1993

数据来源: WILEY