bluuebunny/crossref_metadata_2025 huggingface dataset:
The geometrization of the discriminal process model and the psychophysical functions
Authors: Takiyama Ryuzo
Published: July 2007

Thurstone's discriminal process model is geometrized and discussed from the information‐system theoretical point of view. That is, a probability density function (p.d.f.) based on the discriminal processes is defined in the state space (this is the concept of grasping simultaneously the physical stimulus and its response. A parameter space spanned by parameters of the p.d.f. is defined, and fundamental metrics are introduced into the space based on Fisher's information; thus, the space is considered to be a Riemannian space. In the space, the psychophysical functions are derived as certain geometrical invariants. As the results, when the “discriminal dispersion,” i.e., the distribution of the response (the response function) to the input stimulus is to be Gaussian, the power law and the logarithmic law are obtained as psychophysical laws with respect to the mean values of the distributions. From this, relations between difference thresholds, the discriminal process and the psychophysical function are clarified. At the same time, the formalization of the problems and conclusions in [2] are justified from the information‐system theoretical point of view. Further the functional forms of the response functions are also investigated, and it is shown that almost the same conclusions can be obtained even if the Gaussian assumption is repalced by the exponential, the two‐sided exponential, or the logarithmic Gaussian distributions.
Finite‐element analysis of anisotropic waveguides with tensor permittivity
Authors: Koshiba Masanori , Hayata Kazuya , Suzuki Michio
Published: July 2007

A finite‐element expression for an anisotropic waveguide with a tensor permittivity is derived based on the variational expression in terms of all three components of the magnetic field. Since only the Hermitian condition is imposed on the permittivity tensor, the expression can handle an arbitrary anisotropic dielectric and a gyrostatic material. The spurious modes do not appear in the region of effective index of refraction larger than a specific value. From these points of view, the present finite‐element representation is considered to be one of the analysis methods useful for millimeter waveguides and optical waveguides. In this paper, a waveguide with a rectangular cross section is treated which is a fundamental structure for millimeter‐wave and otical integrated circuits. Specifically, rectangular anisotropic dielectric waveguides and rectangular gyrotropic waveguides are analyzed. The effect of off‐diagonal elements of the permittivity tensor on the guided mode characteristics is investigated.
On the synthesis of constant‐resistance distributed‐coupled‐line networks by stationary responses of periodic impulse train
Authors: Watanabe Toshiaki , Sakagami Iwata , Hatori Kozo , Kuri Takaki
Published: July 2007

In synthesis of multistage two‐wire conductor constant‐resistance distributed‐coupled‐line networks, a method had previously been applied in which the element values are determined from the transient response to the given unit impulse. Until now a method did not exist in which the network is synthesized from the stationary response to the periodic impulse train. This paper presents a method wherein the element values of the n‐section multistage constant‐resistance distributed‐coupled line network are determined from the stationary response to the periodic positive‐polarity impulse train 1 1 1 1 …, or both‐polarity impulse train 1 – 1 1 – 1 …. Simplification of this method is also discussed. The transfer function of the network considered in this paper has both the numerator and the denominator of nth order in z−1, and the element values of the network are uniquely determined from the transfer function. When the network is an all‐pass type, the element values may not be uniquely determined; this is discussed herein. The method of synthesis is simplified by utilizing the fact that, when the network to determine is of all‐pass type, the numerator and denominator of the network transfer function are inverse polynomials of z−1 to each other.
A fast computation algorithm of the two‐dimensional cosine transform using chebyshev polynomial transform
Authors: Morikawa Yoshitaka , Hamada Hiroshi , Watabu Kazuyoshi
Published: July 2007

The two‐dimensional discrete cosine transform (2D‐DCT) is the important orthogonal transform in the pattern recognition of images or highly efficient coding. This paper proposes a new method of fast computation for the 2D‐DCT for N × N (N = 2v) points. It is shown first that the 2D‐DCT can be reduced to a Chebyshev polynomial transform (TPT) and N 1D‐DCT's by rewriting the 2D‐DCT into the residue expression of polynomials. TPT is a polynomial transform with the same structure as the 1D‐DCT, which is defined on the polynomial‐residue ring P[z]/TN(z) with the Nth order Chebyshev polynomial TN(z) as the modulus. Then the successive factorization of the Nth order Chebyshev polynomial TN(z) on P[z]/TN(z) is derived, and by utilizing the factorization, a fast computation of TPT is derived. The computation of TPT is composed only of approximately 2N2 log2 N additions. Consequently, the algorithm of the 2D‐DCT proposed in this paper has slightly less than twice the high speed, compared with the traditional two‐column decomposition method necessitating 2N 1D‐DCT's.
Image signal processing LSI for facsimile
Authors: Tadauchi Masaharu , Tanno Kiyohiko , Hamada Nagaharu , Sato Kunio
Published: July 2007

The basic function of the facsimile reader is to correct the shading distortion (low‐frequency distortion due to low peripheral intensity) produced by the optical system in the analog signal from the one‐dimensional image sensor and to produce the correct black‐and‐white binary signal. Based on quantitative evaluation of the shading distortion, the authors developed LSI for signal processing, realizing a high‐precision binary signal transformation. The LSI first memorizes the shading distortion in the RAM in digitized form and then the information read from the RAM goes to the DA converter in synchronization with the input image signal. Comparing the reproduced analog distortion signal and the input image signal, highly precise distortion correction is realized. In this scheme the analog distortion is proportional to the input signal level and the operation can follow the change of source intensity and the change of manuscript background brightness. This function is realized by division between the reference voltage and the input voltage of the AD converter. The binary slice level is set with an accuracy within ±3%. The proposed LSI was fabricated by 5‐μm N–MOS technique and it was verified that the realized LSI satisfies the requirement for facsimile.
Degradation process and fluctuation mechanism of contact resistance for twisted conductor splice
Authors: Kuribayashi Masashi , Tokuda Masamitsu , Kawaguchi Tokihiro , Fujiwara Mitsugu
Published: July 2007

Dynamic and static properties of the contact resistance of twisted conductor splices have been investigated. The splice resistance in a static condition increases (degraded) with time. This is described in terms of a probability density function in which the logarithm of the splice resistance is regarded as a Markovian process. Furthermore, properties of the splice resistance when different mechanical qualities are involved in it are described by a composite probability density function. The theoretical prediction agrees well with observation. The dynamic properties are attributed to temporal change in the displacement of the conductors and in the contact force of the core conductors which is caused by an external force applied on them. Their dependence is given explicitly and a formula for evaluating the aging effect has been derived. Finally, the validity of this model is confirmed by the experimental results.
Signal smoothing by summation–generalized fejer method and generalized lanczos method
Authors: Imiya Atsushi , Sasaki Toshio , Ogawa Hidemitsu
Published: July 2007

Truncation of a Fourier series causes ripples in the neighborhood of a discontinuous point. This is known as the Gibbs phenomenon. These ripples can be removed by the use of properly weighted Fourier coefficients. The smoothing is the summation method of the series theory applied to the Fourier series. The Fejer method is the Cesàro summation of series applied to the Fourier series. The Lanczos smoothing takes into consideration periodicity of the trigonometric functions. This paper extends the smoothing methods based on the summation so that they can be applied to general orthogonal functions. The Fejer method is developed as a weighted Fourier expansion, to which a geometrical explanation is given. It is shown also that the Fejer method yields a signal identified with a solution to a minimization problem. Periodicity of the trigonometric functions is extended to general orthogonal functions in such a way that the Lanczos method can be extended to cover them.
Minimax observers
Authors: Yahagi Takashi
Published: July 2007

This paper discusses the design of the regulator using output feedback, and describes a method of control using the observer. In the regulator using the observer, the evaluation function is increased, compared with the state‐feedback control. In this paper, the minimax evaluation is adopted, which considers the worst case in regard to the initial state. Consequently, the optimal observer, i.e., the minimax observer can be determined by the proposed method, in the sense that the worst value in regard to the initial state is minimized. Since the initial state is not known in the regulator problem using the output feedback control, the minimax evaluation is practically very important. This paper discusses first the discrete‐time system, and the design of the minimax observer is discussed for the linear quadratic form and the model‐following control problems. Then, the result of applying the idea to the continuous‐time system is shown. It is also possible to design the minimax observer for the continuous‐time system, in the same way as for the discrete‐time system. The proposed method can be applied, not only to the observer with the minimum dimension but also to the observer with the same dimension. As the numerical example, a solution of the minimum problem is presented using the proposed method.
A method for estimating biases in the measurement system of a height finding radar
Authors: Nagaoka Sakae
Published: July 2007

An analytical method is described based on data to be obtained by flight experiments for estimating biases of the range and depression angle measurement systems of a simple height finding radar (called NAMS) which uses a rotating fan beam antenna in a vertical plane. This method is based on the principle that the effects of biases on the height estimation error vary according to the geometric position of an aircraft relative to the radar head. Height estimation errors are estimated using the difference between the measured height of the aircraft by the radar and that by a barometric altimeter aboard the aircraft. Since the height estimation errors of NAMS can be approximated by a linear regression equation whose coefficients include biases of range and depression angle, the coefficients can be estimated by using the least squares method. In this paper, the derivation of the linear regression equation is given first. Then the algorithm for height estimation is described. Finally, the validity of assumptions and height estimation accuracy by the proposed method are examined by computer simulation. As a result, the feasibility of this method for estimating the biases of range and depression angle and the estimation accuracy is shown.
Electromagnetic wave excitation in a two‐dimensional impedance tunnel with a T‐junction
Authors: Uchida Kazunori , Matsunaga Toshiaki , Noda Takeaki
Published: July 2007

As an example of tunnels with a branch and a bend, the one with a T‐junction is selected for analysis of electromagnetic wave propagation when it is excited with a line source. As the boundary condition on the tunnel wall, a surface impedance approximation has been introduced. The calculations have been performed with the introduction of a two‐dimensional model. In the calculation, the tunnel is divided into the source region (Tunnel I) and the remainder (Tunnel II). The field in the former is modal expanded in a series with unknown coefficients; in the latter a Fourier transform is introduced so that the field is treated in the transform domain. The field matching at the aperture is performed in the Fourier‐transformed domain so that the unknown expansion coefficients described above can be obtained as the solutions of an infinite set of simultaneous equations. Finally, the numerical results are compared with those of a model experiment and the effectiveness of the surface impedance approximation is discussed. It is found that the numerical and experimental results agree rather well for the electric field intensity distribution in Tunnel II.
Analysis of the CSMA/CD protocol with deterministic contention resolution
Authors: Kimura George
Published: July 2007

The CSMA/CD DCR (CDMA/CD with Deterministic Contention Resolution) is a multiaccess protocol for local area networks. With this protocol a packet collides with another only once at most, so that high throughput and small delay characteristics are achieved. This paper presents a method of analyzing this protocol using a slotted model. First, for the equal arrival rate case, numerical results are obtained and the performance is evaluated on a throughput‐delay characteristic basis. As for the delay characteristic, not only its average but also its variance and distribution are evaluated. Also, the delay characteristics for right‐ and leftmost stations are clarified. Next, the unequal arrival rate case is analyzed and the delay characteristic is studied. Finally, the performance of CSMA/CD DCR is compared with those of CSMA/CD and token scheme, and the application field of CSMA/CD DCR is clarified.
Priority Exhaustive‐Service‐Type Multipacket Transmission
Authors: Komatsu Masaharu , Mayeda Wataru
Published: July 2007

Multipacket transmission achieves higher channel utilization efficiency than single‐packet transmission, and also improves packet delay. Some multipacket transmission systems have been proposed. However, none has been proposed yet which takes account of priority level. This paper proposes a Priority Exhaustive‐Service‐Type Multipacket Transmission (PESMPT) method. This method is modeled as an exhaustive‐service‐type queueing system having traffic sources with different priority levels. We analyze PESMPT for the case of two priority levels and derive channel utilization efficiency, number of packets in a frame, packet transmission delay, etc. Also, from numerical examples, the performance of PESMPT is clarified and is compared with those of non‐priority exhaustive‐service‐type multipacket transmission method and HOL priority method which is the most general single‐packet transmission method with priorities.
Concept of space modification and a theory of function measuring the centrality (or mediality) of a point in a network
Authors: Shinoda Shoji , Sengoku Masakazu
Published: July 2007

Often, in a system with a network structure, such as the communication network, traffic network and social relationships, the centrality of a point is discussed. The centrality of a point is usually measured by its relation to other points, and the distance has been used as a measure for the relation. Recently, a method based on the capacity has also been proposed. In contrast to the past theory of centrality function, which discriminated the cases into the relation between points into the distance and the capacity, this paper presents a unified theory by introducing the concept of modification of the space with respect to a point. Based on the modification of the space, the axiomatic system concerning the centrality and semi‐centrality functions are newly defined, extracting the properties shared by the past centrality functions. The characterization of the real‐valued function defined on a point is made based on the proposed axiomatic system, and it is shown that the proposed theory includes the past major results concerning the centrality function. Finally, the theory is applied to the network, where the weight is assigned to the point, and the length and capacity are assigned to the edge. Thus, the theory is a generalization of the centrality function which is applicable to the network, where weight is assigned to the point and the length and capacity are assigned to the edge.
Vector quantization of speech signals using principal component analysis
Authors: Kohata Minoru , Sone Hideaki , Echigo Hiroshi , Takagis Tasuku
Published: July 2007

A new method of designing a vector quantizer is presented for bandwidth compression of speech signals, and some experimental results are shown. In this method, spectral parameters are extracted first from the DFT spectrum of input speech signals using a psychological frequency scale‐the so‐called Mel scale. This parameter is called the Mel‐scaled spectrum. The number of Mel‐scaled spectrum is reduced and the cepstrum of this parameter is calculated. Then this Mel‐scaled cepstrum is vector quantized and the codebook‐vector of the vector quantizer is determined by the algorithm using principal component analysis. With this algorithm, codebook‐vectors can be designed considering the statistical characteristics of the Mel‐scaled cepstrum. Also, the reduction of parameters by Mel‐scale can decrease the size of the codebook memory without greatly degrading the synthesized speech quality.

Using the forementioned method two codebooks are designed: one contains 256 vectors, and the other contains 2048 vectors. The quantization error is compared with those designed by the well‐known LBG algorithm. The simulation results show that the codebooks designed by the proposed method present less quantization error and degradation of synthesized speech quality than those designed by LBG algorithm.
Optical observation of finite amplitude ultrasonic fields
Authors: Nishida Yukihiro , Asada Ichiro , Nakajima Masato , Yuta Shin‐Ichi
Published: July 2007

When a coherent light is passed through an ultrasonic field of finite amplitude, the diffraction spectrum has an asymmetrical form around the Oth order component due to the harmonic generation corresponding to the waveform distortion in the propagation of ultrasound. This paper demonstrates that the asymmetry depends on the phase relationships among the harmonic components of the ultrasound. A method is proposed which can reconstruct the original ultrasonic waveform by a simple measurement and calculation. The method is to separate the symmetric and antimetric components of the diffracted light by calculating the sum and difference of the positive‐ and negative‐order components, and to determine the amplitude and phase from the sum and the difference, respectively. Using the proposed method, the CT techniques are applied to the optically measured data which are a line‐integral of the ultrasonic pressure. The ultrasonic field distribution is visualized for arbitrary cross section for each harmonic component, making it possible to observe the two‐dimensional distribution of the harmonic generation accompanying the propagation of finite amplitude ultrasound.
Numerical analysis of transmission lines with branches and junctions
Authors: Ichikawa Satoshi , Nakamura Yuichi
Published: July 2007

Some of the analyses which are important in practice are: the analysis of induction noise between lines on the printed board; and the analysis of extraordinary phenomena in the multiline transmission system. These problems can be reduced to the transient analysis of the transmission‐line network composed of a number of transmission‐lines with different phases, their branches and junctions, as well as a number of lumped‐constant elements. By the analysis in the s‐domain through Laplace transform, the general solution for the basic equation for the transmission‐line is obtained containing arbitrary constants, and the arbitrary constants can be determined from the system of linear equations derived from the boundary conditions. This paper presents a method of deriving this system of linear equations for the case with only lumped sources and for the case with distributed sources. By determining the arbitrary constants, the solution is obtained in the operator domain, and the time‐solution is obtained by the inverse transform. The solution in the time‐domain is obtained by the numerical inverse Laplace transform, and the computation is performed by substituting a sequence of complex values into s. The effectiveness of the proposed method is verified by applying the method to several examples.
An adaptive equalizer based on parallel computation scheme
Authors: Hashimoto Koichi , Kimura Hidenori
Published: July 2007

Equalizers which compensate the transmission characteristics of the transmission channels are important for ensuring the quality of data transmission and are inevitable especially in the data transmission using telephone networks.

This paper describes a method of applying the parallel architecture (PA) which we have already proposed to an adaptive equalizer which utilizes the recursvie least square (RLS) method. The RLS method which is used to estimate and update the parameters of equalizers, is attractive as an effective algorithm because of its fast conversion. However, the complexity of its computation makes this method less popular than the least mean square (LMS) method, especially for adaptive equalizers which require the fast update of the parameters.

Utilizing the parallel architecture with the method described herein it is able to execute the RLS method with the same amount of calculation time as that of the LMS method. The parallel architecture is expected to be applicable in practice because it has an architecture of regular structures and localized interconnections which are suitable for implementation in VLSIs.
An analysis of the multi–channel CSMA/CD protocol by non–slotted model
Authors: Kimura George
Published: July 2007

The multi‐channel CSMA/CD (M‐CSMA/CD) is a multiple‐access protocol which is suitable for broadband bus local area networks consisting of parallel channels. This protocol can achieve such good characteristics as a large capacity and a high degree of adaptability. Most of the CSMA/CD and M‐CSMA/CD protocols have been analyzed by slotted models in the past. There is one customer at a terminal (finite source) and he sends and/or receives data by the M‐CSMA/ CD protocol. The time required for the transmission start to be detected by another terminal within the same network is approximated by an exponential distribution, resulting in an irreducible Markov model. This paper presents a method of analyzing this protocol using a non‐slotted model. Numerical results are compared with computer simulation results and the approximation accuracy is discussed. The difference of the numerical results for non‐slotted models from those for slotted models is also discussed.
Synthesis of stray‐insensitive switched‐capacitor circuits which realize several transfer functions simultaneously
Authors: Nishi Tetsuo , Kunihiro Takushi
Published: July 2007

It is important in implementing circuits as LSI to realize several transfer functions by a single circuit. This paper considers a problem of realizing simultaneously several transfer functions with the same denominator polynomial by a single stray‐insensitive switched‐capacitor circuit, and presents a synthesis method. First, we derive a standard form of a system equation realizing 2n transfer functions of z−1 of degree n. Then we propose a technique for realizing the system equation as a stray‐insensitive switched‐capacitor circuit. As a result, it is shown that the 2n transfer functions above are realized by at most (2n + 3) (n + 1) capacitors and at most (n + 1) operational amplifiers. Finally, two examples are presented for stray‐insensitive switched capacitor circuits realizing four transfer functions of degree 2: one is realized by using two operational amplifiers, and the other needs three operational amplifiers.
Performance degradation of PN matched filter with clock frequency offset and its compensation
Authors: Hasegawa Takaaki , Nakagawas Masao
Published: July 2007

One of the important problems in the spread‐spectrum communication system is the despreading of the received signal in the receiver. The CCD delay‐line matched filter is a kind of device realizing the despreading. It has a problem in that the sampling frequency must be exactly the same as the clock frequency of the spread signals contained in the received signal. When there is an offset between the two frequencies, the performance of despreading is degraded in the delay‐line matched filter. However, for this problem, no quantitative analysis has been made so far. This paper presents a theoretical analysis by the new method and under several assumptions, for the degradation of the peak output in the CCD delay‐line matched filter when there exists an offset of the clock frequency. The results are compared with the results of computer simulation. Based on these results, a CCD matched filter loop is proposed which has the function to follow the various frequency offsets. Its performance is demonstrated by the simulation.
Four polarizations filter for frequency reuse
Authors: Umehara Tadatoshi
Published: July 2007

As a means to remedy the crowded use of frequencies in wireless communication, a system based on the orthogonal two‐polarizations with the same frequency is employed, which doubles the frequency utilization. This paper proposes a method which increases the use of the frequency by four times by using the four‐polarizations, adding two‐polarizations between the orthogonal polaritions. For this purpose, a device is needed which can select one of the four polarizations at the single frequency. The principle of the polarization rotation device to be used for such a purpose is described. The device is shown by an experiment to be practically useful.
Scattering of Hermite‐Gaussian beams by parallel conducting cylinders
Authors: Yokota Mitsuhiro , Takenaka Takashi , Fukumitsus Otozo
Published: July 2007

The problem of a Gaussian beam with the spatial energy concentrated along the propagation axis is important in engineering applications. This paper studies scattering of two‐dimensional Hermite‐Gaussian beams by several parallel conducting cylinders located arbitrarily. First, the relation between the conventional beam modes and the complex beam modes proposed by Siegman is used for expression of a Hermite‐Gaussian beam in terms of multipoles with complex points. Next, the scattered field of each multipole field by cylinders is derived. The scattered fields of a conventional beam mode are represented in terms of those of complex‐source‐point multipole fields. As a numerical example, the effect of the spot size and that of the displacement of the propagation axis are studied in the case where a Gaussian beam is incident with the Bragg angle on the array of eight cylinders. It is found that the directivity of the diffraction of the order ‐1 is increased with the spot size and the maximum can be found in the direction almost equal to that for a plane wave incidence.
Inversion for 2‐D systems
Authors: Shimonishi Jiro , Hinamoto Takao , Maekawas Sadao
Published: July 2007

This paper describes a method for constructing an inverse system with inherent delay for causal two‐dimensional (2‐D) systems described by the Roesser state‐space model. In other words, the weakly causal 2‐D systems proposed by Eising are considered as 1‐D dynamic systems such that each element of the coefficient matrix is a rational function of one variable. It is shown also that an inversion with inherent delay for causal 2‐D systems can be discussed in general from a viewpoint of 1‐D dynamic systems. The features of the method are as follows: (i) the theory in 1‐D dynamic systems can be applied to the construction of 2‐D inverse systems; and (ii) a weakly causal inverse system can be obtained more easily from the viewpoint of a local state‐space model.
Scheduling of extended marked graphs
Authors: Onaga Kenji
Published: July 2007

The extended marked graph EMG = (V, E, c, d, p±, τ) is an excellent analytical tool for systems such as multi‐PERT and flow‐shop, where nondestructive resources are cyclically shared. This paper present a quantitative analysis for EMG scheduling (f, s) and describes the method of computation. fx (t) represents the number of firings of node x until time t and sx (t) is the kth firing time of node x. There are two kinds of rules, free and conservative types. The computation algorithm for scheduling and the method of determining the executability of the schedule are derived for each type.
Statistical design method of loss budget for the optical subscriber transmission system
Authors: Yamashita Ichiro , Kikushimas Koji
Published: July 2007

In the transmission system for the trunk lines, where a high reliability, i.e., a severe loss requirement is imposed, the worst condition is usually assumed in the design for the individual gain and loss of the transmission devices and media. In this paper this method is called the worst‐case transmission loss budget method or the worst‐case design. Although this method is reliable, it often contradicts the economical requirement in the subscriber transmission system. This paper proposes a design method for the transmission system, called the statistical loss budget method or statistical design method. Here, the transmission characteristics of the devices and media are assumed to follow statistical distributions with certain ensembles, and assuming that included statistical phenomena are always independent, the transmission performance is secured at a certain level with the specified danger level (significance level). By the proposed statistical design method, the economical requirement can be satisfied while maintaining the overall transmission performance of the system. In the optical transmission system, where the transmission loss is less compared with the metallic system, it is a great advantage of the statistical design method that the transmission length can be increased. In the design example where the statistical method is applied to the design of an optical subscriber transmission system, the transmission length is increased to approximately 1.8 times compared with the worst‐case design.
Development of several ohp equipment of physics using moiré patterns
Authors: Kitagaki Ikuo
Published: July 2007

This paper reports on several simple OHP equipments for education using Moiré patterns. The first equipment is concerned with centrifugal waves. The Moiré pattern is produced by superposing two specified patterns composed of straight lines and curves. The two patterns are determined as functions of the wave propagation velocity. The second is the fluid model used in demonstrating such notions in vector analysis as divergence. The spiral travelling wave is simulated using the reverse Moiré, which is a counterpart of the Moiré technique. The third is the equipment to simulate the electric lines of force produced by a pair of point charges and is used in teaching electromagnetics. The patterns are designed also for easy understanding of Moiré phenomena. This paper describes the design procedures for the patterns, indicating several points to be noted in the actual application of the equipments.
Design of digital nyquist filters based on the measure of squared errors at sampling points
Authors: Kida Takuro , Fukuda Yutaka
Published: July 2007

This paper describes design methods of the digital Nyquist filters based on the squared errors of the impulse response at equally spaced sampling points except one. First of all, for a specified pole of a transfer function, we consider the pole location which causes a problem when we use the residue formula proposed by Kida and Ohsumi to minimize the above mentioned squared errors. Then, assuming about 6 to 8 degrees for the orders for transfer functions, we consider a method which gives a favorable pole arrangement. We make an examination about a simple method of determining a pole arrangement which provides a favorable characteristic such that the squared errors at equally spaced sampling points except one point are about 10−5 and that the stopband attenuation is about 50 dB. Furthermore, in order to realize a large stopband attenuation which is required in the design of digital Nyquist filters, propose a design method of a transfer function based on a quadratic programming specifying the attenuation at a point in the frequency domain specified in advance. We show its effectiveness by examples. Finally, for the design of digital Nyquist filters using an interpolation method based on the sampling theorem of non‐equal space derived by Kida and Fukuda, we consider an example which indicates that transfer functions obtained by the above two design methods are appropriate.
A class of nonuniform coupled transmission lines and their equivalent circuits
Authors: Kobayashi Kunikatsu , Saito Nobuji
Published: July 2007

Y‐type and Z‐type parabolic‐taper single‐mode transmission lines and their equivalent circuits are first discussed. Then, by superposition of two of the above single modes, the TEM mode along a parabolic‐taper coupled transmission line (PTCTL) is analyzed. According to the choice of Y‐type or Z‐type for tapered single modes and the choice of combinations of balanced‐unbalanced modes or open‐short line modes as two independent superposed modes, there can be six types of PTCTL. Their equivalent circuits are also easily shown. Through the superposition of the voltages and currents of two Y‐type single‐mode parabolic‐taper lines, a Y‐type parabolic‐taper coupled two‐wire line is obtained. Similarly, from two Z‐type single‐mode parabolic‐taper lines, a Z‐type parabolic‐taper coupled two‐wire line is obtained. Furthermore, from a Y‐type parabolic‐taper line and a Z‐type parabolic‐taper line, we derive a mixed type of parabolic‐taper coupled two‐wire line. In any case there are two forms of combination, balanced‐unbalanced modes and short‐open line modes as superposition of two independent modes. An obtained nonuniform coupled two‐wire line does not always have the same taper. A special case of interest is that in which one of the two wires of a coupled line has decreasing taper and the other has increasing taper. Finally, a low‐pass filter is designed by the use of nonuniform coupled transmission lines and it is shown that the line length along the axis can be reduced.
Numerical analysis of diffraction from a sinusoidal metal grating
Authors: Yasuura Kamenosuke , Murayama Masanao
Published: July 2007

Diffraction of plane waves by a metal grating of a sinusoidal cross section is investigated theoretically by considering a finite conductivity of the material. The analysis is based on the mode‐matching method with a smoothing operation. The numerical results of the diffracted power from a sinusoidal gold grating are presented with sufficient accuracy for both P‐polarization and S‐polarization. The results have been compared with those for perfectly conducting gratings. It is found that: (i) the reflected power is reduced due to loss compared to the perfectly conducting case, and the acuteness of the anomalous diffraction phenomenon called Wood's anomaly is decreased; and (ii) another anomaly called plasmon anomaly is observed in the case of P‐polarization. The latter cannot be observed in a perfect conductor.
Multiport power combining transmitter for multibeam satellite communications
Authors: Egami Shunichiro , Kawai Makoto
Published: July 2007

A multiple beam power combining transmitter which has the flexibility to adapt beam power to varying beam traffic is proposed. The new multiport power combining network consists of a power‐dividing multiport directional coupler, multiple amplifiers and a power‐combining multiport directional coupler. The multiport directional coupler consists of multiple quadrature hybrids. Since each amplifier commonly amplifies signals to each beam, the power allotment to each beam can be changed with flexibility. The concept and configuration of the multiport directional coupler which divides and combines input signals are described. Also, the effects of uneven gain and phase distribution or failure of amplifiers are represented theoretically. Implementation to 8‐or 10‐beam systems is shown. Finally, the characteristics of the 8‐port experimental transmitter utilizing 1.5W FET amplifiers and branch line type hybrids are shown.
Vowel recognition using an LPC deviation model
Authors: Kumazawa Itsuo , Iijimas Taizo
Published: July 2007

When the linear prediction coefficients (LPC) are used as a feature parameter of speech, a problem in speech recognition is the variation of LPC due to the difference of the speaker and the effect of the preceding or succeeding utterances. Because of this variation, LPC is distributed in a certain region in the LPC space. This paper proposes a method which approximates the region of distribution by a linear manifold model described in [1], and recognizes the category permitting the variation of LPC. The method is applied to the vowel recognition of CV syllable, and its usefulness is verified experimentally. It is shown first by spectrum analysis experiment that the linear manifold model is useful in the approximation of the variation of the vowel spectrum due to the preceding consonant. Second, a recognition experiment is carried out based on the model, and it is shown that the recognition rate can be improved by a simple model of linear manifold which is suited to computation.
A rearrangement algorithm for three‐stage switching networks
Authors: Ohta Satoru , Ueda Hiromi
Published: July 2007

In the three‐stage rearrangeable switch‐ing network, an internal blocking can occur. However, such a blocking can be eliminated by rearranging the already set‐up paths, and thus the network can satisfy any connection requirement. To eliminate this internal blocking, a successive rearrangement of more than one already set‐up path is required. The sequence of the paths to be rearranged can clearly be represented by extending the notion of the connection chain introduced by Gotoh. This paper presents a sufficient condition for the Internal blocking to be eliminated by the rearrangement in the extended connection chain, which is a basis for the rearrangement algorithm. It is also verified that the rearrangement algorithm proposed by Gotoh satisfies the sufficient condition. Based on these results, a connection chain is shown in which the internal blocking can be eliminated by the rearrangement. The algorithm to search for the connection chain and to perform the rearrangement is presented. Compared with past methods, in the proposed method, a fewer number of paths is distorted. The usefulness of the method is examined by a simulation.
σ gi/m/s/k queues with mixed batch renewal inputs
Authors: Machihara Fumiaki
Published: July 2007

This paper presents the analysis for the finite capacity queueing model with two independent mixed batch renewal inputs. The analysis is presented for the steady‐state distribution at an arbitrary time and the steady‐state distribution immediately before the arrival for each type of customers. The results can be applied to the models of various kinds of strategies such as delay‐delay, delay‐loss and loss‐loss. The structure of this paper is as follows. First, a simple numerical calculation procedures is proposed for the distribution at an arbitrary time which, compared with past methods, drastically reduces the computational complexity. Then the relationship is established between the distribution at an arbitrary time and the distribution immediately before the arrival, using the rate conservation principle in the theory of piecewise Markov process. Using this relationship, one distribution can easily be derived from the other. The individual blocking probabilities, which are the most important performance measures, are derived from the distribution immediately before the arrival. Finally, several examples are presented in order to discuss the effects of the interarrival distribution and the batch‐size distribution on the individual blocking probabilities.
A multiplexing system for digital transmission and process in vehicles
Authors: He Aiguo , Kawamatas Akira
Published: July 2007

At present, the vehicular electronic system is composed of several independent subsystems. By contrast, this paper proposes an integrated system where the same functions are realized in a more reasonable and economical way, utilizing the digital multiplex communication and distributed control. The system aims at optimization of the connections and control of the components, considering only the distances among the subsystems and components, independently of their kinds and functions. To improve the economy, reliability and flexibility, the system is composed of a ring transmission system and a distributed processing system using the microprocessors and optical fibers. This paper discusses the functions and structures of the transmission and processing devices composing the system. The optimum number of transmission and processing devices as well as the processing ability of the system are examined.
Transmission characteristics of PSK signals in satellite communication with nonlinearity and bandwidth limitation
Authors: Katayama Masaaki , Morinaga Norihiko , Namekawa Toshihiko
Published: July 2007

This paper reports on the results of analysis of the error‐rate performance when a PSK signal is transmitted through a satellite transponder. A waveform analysis is performed for the in‐phase and orthogonal components of the output from the nonlinear satellite transponder. The nonlinearity of the satellite transponder is represented by a bandpass hard limiter. In the analysis, the effect of both the ground transmitting and receiving filters are considered. As a result, the effect of the receiving filter on the signal is indicated clearly, which heretofore has been difficult in theoretical analysis. The reason for the degradation of the error‐rate performance in the bandpass hard limiter system is also clarified by the theoretical analysis, which has been pointed out by experiment and simulation.
Numerical method for analyzing transient and steady states of sine wave oscillator circuit with stiffness
Authors: Okumura Kohshi , Kishima Akira , Yasuda Hisashi
Published: July 2007

This paper proposes a method for analyzing the transient and steady states of a sine wave oscillator circuit with reactive elements which have large differences in their values. These reactive elements can be divided broadly into three categories: elements for determining the frequency of the oscillation; very small elements such as stray capacitors in the transistor; and very large elements such as by‐pass capacitors. The circuit equation is represented by an autonomous nonlinear differential equation with the values of these elements. There are remarkable differences in magnitude between the eigenvalues of the linear parts of the equation. In this paper, first, we describe the method for solving numerically the differential equation regardless of the stiffness by the asymptotic method developed by Krylov, Bogolyubov and Mitropolskiy. Second, we present the method for obtaining solutions of the differential equation with regard to the stiffness by combining the asymptotic method with numerical integration. Especially, when we obtain the transient solution, we demonstrate that the application of the interpolation method to the asymptotic method reduces the computing time considerably. As examples, we consider the CR sine wave oscillator circuit using the Ebers–Moll model of transistors.
Design of IIR nyquist filter pairs with equi–ripple stopband attenuation
Authors: Takebe Tsuyoshi , Matsumoto Toyoji
Published: July 2007

This paper deals with a design of digital transmitter and receiver IIR Nyquist low‐pass filter pairs for data transmission. The transmitter and receiver filters are required to limit the spectrum bandwidth of a transmitting signal and a received signal, respectively, and to have zero intersymbol interference when the filters operate in a cascade. Due to the bandlimiting requirements, the sampling frequency Fs = 1/Ts for the filters must be larger than twice the data transmission rate 1/T. This paper supposes the receiver filter followed by the time domain equalizer. The filter design proceeds as follows: first, the transmitter and receiver filters are designed to have the same transfer function with a stopband equiripple attenuation, considering the amplitude characteristics only. The filter transfer function is designed by using s – z transformation of the known analog elliptic filter, realizing the transition band characteristics with the preassigned roll‐off factor. The method does not require any iterative approximation. Secondly, the output of the receiver filter is decimated to the data symbol repetition rate T, then equalized in the time domain. The time domain equalizer consists of a linear or a decision feedback circuit, using an MS adaptive algorithm. The amount of delay given to the training signal supplied to the equalizer affects the residual errors. Let the order of the equalizer (numerator and denominator has the same order) denoted by n. Then an optimum delay is found to be equal to nT for the linear feedback circuit and (n/2)T for the decision feedback circuit.
Minimum confluent cut of a directed graph and its application to the block replacement problem in VLSI design
Authors: Kajitani Yoji , Tsuji Katsufumi , Chen Ray R.
Published: July 2007

Assume a situation in which a block is required to change its relative position at the step where placement and routing in the VLSI layout design has been completed. We formulate a problem of minimizing the number of steps for modification, assuming that we need a step of one unit for rerouting one channel. Then we obtain a solution. For routing, we assume a channel routing style performed channel by channel on the grid determined by a design rule, and that a block movement is required by such slight increase of the width that a new wiring requirement is generated between blocks. The problem is reduced to that of finding an A‐confluent cut with total minimum weights for an arbitrarily specified edge set A in a directed graph with weighted edges. By an A‐confluent cut we mean a cut such that the orientation of each constituent edge is the same with respect to edges in A. Although it is a fundamental notion in graph theory, it appears to have been given little consideration.
Analysis of mobile antenna in UHF band
Authors: Nishikawa Kunitoshi , Asano Yoshikazu
Published: July 2007

Theoretical and experimental studies are made on an antenna mounted on the roof of an automobile. The theoretical model of an automobile body and a calculation technique based on GTD are developed to calculate the input impedance and vertical plane patterns of a quarter‐wavelength monopole in the 300–900 MHz band. The theoretical model consists of three perfectly conducting plates. From a comparison of calculated and measured results it is seen that the effect of the body and the earth can be examined well with the theoretical model. The results of the pattern calculation show that the radiation patterns depend largely on the configuration of the automobile body.