bluuebunny/crossref_metadata_2025_split huggingface dataset:
Convergence characteristics of the kalman‐type equalizer in decision‐directed mode
Authors: Sakaki Hiroshi , Shintani Sotokichi 
Published: July 2007

AbstractIn general, in the adjustment of its tap weight, the automatic equalizer requires the reference signal in addition to the input to the equalizer. For the convergence to be correct, the reference signal should be the equalizer output after the convergence is completed correctly. Since this is impossible in practice, a decision‐directed operation occurs wherein the equalizer output during tap weight adjustment is given to the decision part and the output of the decision part is used as the reference signal. In such a case, the adjustment of the tap weight is not exactly correct.This paper shows first that the characteristics of the cascade system (which consists of the transfer characteristics of a Kalman‐type automatic equalizer after tap weight adjustment, operating by following the reference signal from the decision part) and the characteristics of the transmission channel can be determined directly from the signal type and the characteristics of the transmission channel and the characteristics of the decision part. In the above reasoning, the characteristics of the cascade system are obtained as the cross correlation between the transmitted signal and the output signal from the decision part. Then the mechanism to arrive at the correct convergence is described for the automatic equalizer, based on the knowledge obtained in the analysis of the cascade system. Finally, a Karhunen‐Loéve type decision‐assist fixed equalizer is proposed, which compensates the frequencygain characteristics of the transmission channel and assists the correct decision of the decision part.
Polymer thin film optical waveguide
Authors: Kato Isamu , Komatsu Masatoshi , Kawamoto Shigeharu , Matsumoto Yasushi 
Published: July 2007

AbstractPolymers that are suitable for thin films are also used as materials for hybrid optical IC's; however, it is not easy in general to get a high refractive index change in the waveguide using these materials. To remove this difficulty, we have used copolymers of glycidyl methacrylic acid and methyl methacrylic acid, doped with cinnamic acid; this acid was directly photolocked, by ultraviolet exposure, to the epoxy rings of glycidyl methacrylic acid. Eventually, a refractive index change as large as 2% was achieved. Single‐mode optical waveguides with various widths were fabricated by means of the present method, and the dependence of the loss on the waveguide width and the loss in a bend were measured.
The theoretical analysis of stoneley waves propagating along an interface between Zno and glass
Authors: Shimizu Yasutaka , Irino Toshio 
Published: July 2007

AbstractConventional surface acoustic wave devices mainly use a Rayleigh wave, propagating along the surface of the substrate. Therefore, they require packaging. How—ever, the cost of packaging is high. Also, if the packaging quality is poor, water drops accumulate on the substrate surface at low temperature and the device may malfunction. This paper describes devices that do not require packaging and examine Stoneley waves, propagating along the interface between a piezoelectric ZnO layer, which can excite a surface wave, and a glass layer, in which material constants can be changed relatively easily. We find the range of the material constants of the glass which, in combination with ZnO, can generate Stoneley waves. We obtain the velocity, electromechanical coupling coefficient and energy concentration at the interface within this range. The effect of the material constants on these parameters is also considered. It is found that there are glasses that support Stoneley waves and others that do not.
Distortionless transmission of a quantized signal through band‐limited channels
Authors: Kishi Genya , Sakaniwa Kohichi 
Published: July 2007

AbstractIn this paper, a quantized signal is expressed by step functions defined in a finite time interval. The quantized signal has infinite frequency spectra and is distorted when transmitted through band‐limited channels. This paper examines the recovery of the quantized signal from the received signal after passing through an ideal lowpass band‐limited channel. The isolated signal which is zero out of the finite time interval can be recovered. The proposal recovery algorithm is based on an algebraic method and does not contain limiting operation.
Pattern synthesis of spherical circular array antenna by conjugate gradient method
Authors: Horiguchi Susumu , Sawaya Kunio , Ishizone Takayuki , Mushiakes Yasuto 
Published: July 2007

AbstractIn this paper, the spherical circular array antenna pattern is synthesized and the results are compared with the planar circular array. Since the pattern function is complicated, analysis of pattern syntheses of solid surface arrays such as the spherical array becomes difficult. Herein, pattern synthesis is done numerically by minimizing the mean‐square‐error between the desired and synthesized power patterns using the conjugate gradient method. This method is found to be effective in the pattern synthesis of the spherical array. Calculations show that when elements with sharp patterns are used in the array, phase control is more advantageous in practice than amplitude control. Also shown here is the excitation method by which a circularly polarized pattern along the apex direction can be obtained when turnstile antennas are arrayed conformally on the sphere. With this excitation method, the pattern is synthesized and the axial ratio of polarization for main‐beam scan degrades less for spherical than planar array. Furthermore, for spherical array the axial ratio can be improved by placing the elements on a conducting sphere.
Signal modification schemes facsimile based on majority logic
Authors: Suzuki Teruaki , Takebayashi Tomoyoshi , Imai Hideki 
Published: July 2007

AbstractRecently, numerous researches have been made on data compression for digital facsimile transmission and several papers reported on the coding system in which certain signal processing is applied to the local part of the original image before encoding. This facilitates the encoding and improves the data compression rate. This paper proposes a new system which utilizes a signal processing based on the majority principle. This system can be implemented relatively easily by hardware. The image quality reproduced by this system is quite acceptable and can be improved by high‐density sampling. In this paper quantitative analysis is made based on the calculation of entropy and the ideal data compression rate when this signal processing system is used as a preprocessing. A considerable improvement of the data compression rate is shown. In addition, comparison between the proposed system and the existing conventional systems is made.
Characteristics of Ta and Mo thin films deposited by high current ion beam sputtering
Authors: Ishii Kiyoshi , Naoe Masahiko , Yamanakas Shun'Ichi 
Published: July 2007

AbstractThis paper uses a convenient ion beam sputtering setup to sputter tantalum and molybdenum. The Ta and Mo films so obtained are investigated concerning their structures, electrical properties and their relations with the processing conditions. The ion source used is a variant of the conventional duoplasmatron type and is operated at an ion current higher than 50 mA in Ar surrounding gas at 10‐4 torr. The Ta film possesses three different crystal structures: amorphous, α and β phases, depending on different sputtering conditions. The relations between structures and conditions are obtained. For the Mo film the structures obtained, on the other hand, are all the same as bulk. However, it is found that with varying processing conditions, the crystallite size of Mo film varies and the resistivity depends strongly on the crystallite size. Consequently, for given suitable deposition rate and substrate temperature, Mo films with low resistivity or resistivities close to the bulk value can be obtained whereas these cannot be obtained by conventional evaporation or other sputtering methods due to crystallite size increase.
Stability of autonomous nonlinear networks and resistance matrix
Authors: Suzuki Yoshihiko 
Published: July 2007

AbstractThe first half of this paper discusses the stability of the zero solution (equilibrium point) of the time‐invariant nonlinear active network. The stability of the zero solution depends on eigenvalues of equilibrium points of the matrix K which is determined by resistance matrix and connection matrix. The matrix K is expressed explicitly in terms of the resistance matrix R and connection matrix Q. Therefore the stability of the zero solution is determined by the connection method and the properties of the resistance. The second half discusses the global behavior and conclusions similar to those in the first half are derived except such additional condition that capacitance and inductance are linear and resistance is nonlinear. The actual passivity of the network can readily be examined by this method.
Stability theorems for two‐dimensional digital filters and two‐dimensional first‐order time‐delay digital filters
Authors: Okamoto Jiro , Yamashita Kazumi 
Published: July 2007

AbstractThere has been some interest in two‐dimensional digital filters (2D‐DF) which deal with multi‐dimensional information, such as pictures, earthquake waves, etc. If a reversal (recursive) 2D‐DF is composed of adders and resistors in an analog manner, the stability of the system differs from that of the ordinary 2D‐2F without any time element due to minor time delay of adders approximated by linear delay elements. However, if the coefficients of the filter take space‐symmetrical values, stability conditions of both are identical. Hence, the difference has never been noted. We found this fact both experimentally and theoretically and studied each stability condition of the filters for both cases, having infinite and finite constructions. Further, studies were made on mutual relationship between those stability conditions. The 2D‐2F with finite construction treated here is restricted to the case where the size of its lattice is a MxN rectangle.
Integration function and modeling of the central nervous system in forearm movement control
Authors: Taguchi Hideo , Fujii Katsuhiko 
Published: July 2007

AbstractIn a description of the function of the central nervous system in forearm movement control, the structure of the central nervous system must be considered, together with the control function produced by that structure. In this paper, the motor signal is assumed to originate from the brain, and the forearm movement is defined as the combined cooperative processes (integration) of the reflexes in various portions of the central nervous system, including the brain reflex. Based on this concept, the macroscopic mechanism of the central nervous system is described insofar as this is possible. The forearm movement induced by visual stimulation is then considered, and the response is measured in the frequency domain. A model is constructed for the central functions that describes the frequency response over a relatively wide range and agrees well with the macroscopic mechanism of the central nervous system. This model can be regarded as representing the control‐information processing mechanism and function of the biological system in response to the external environment, reflecting the functions of the higher‐level portion of the central nervous system, i.e., the brain. With the proposed model the behavior can also correspond to the functions and mechanism of the lower levels, i.e., the brainstem‐spinal system, which seems to imply that the brain and brainstem‐spinal systems are similar in functional structure but process different information.
A new approach to the two‐dimensional placement problem of wire congestion in Master‐Slice LSI layout design
Authors: Jung Junghwa , Hirayama Hiroshi , Goto Satoshi 
Published: July 2007

AbstractAs the objective functions for the placement problems for LSI and printed circuit board, the minimization of the total routing length and the minimization of the maximum min‐cut density have been used. These quantities are considered to reflect the objective of the layout problem (100% wiring ratio) globally. However, since they do not reflect local congestions of wiring, they are often inadequate as an objective function. This paper introduces a new concept of wire‐congestion of segments to represent the degree of local wire congestion. As an objective function, the minimization of the wire conjection of segments is proposed. An efficient heuristic algorithm is developed to minimize this objective function and the results of program experiments are presented to show its effectiveness. As a result of experiments, it was found that the maximum value of the wire‐congestion of segments became smaller as the total routing length became samller and that the former became larger as the latter became larger. Also obtained experimentally was a control parameter (wire‐congestion parameter) which simultaneously makes the total routing length short and the maximum of wire‐congestion small.
Calculation method for scattering cross section of a dielectric sphere considering resonance phenomena
Authors: Ando Toshikazu 
Published: July 2007

AbstractThe scattering cross section of the dielectric sphere was expressed in infinite series by Stratton. However, this series is difficult to calculate. In the conventional calculation, the applicable ranges of parameters are limited and the number of terms required for infinite series calculation is not clear. Further, the relation between the resonance of dielectric spheres proposes a new calculation method. The fundamental nature of the resonance of the dielectric sphere is discussed and calculation methods for spherical Bessel functions of complex variables and spherical Hankel functions required for scattering cross‐section calculations are presented. The resonance characteristics of the dielectric sphere are calculated with various parameters and the method of determining the number of terms in the calculation of infinite series is examined. This method is applicable for the calculation of scattering wave from the infinite dielectric cylinder.
Optimum magnetic circuit design for small DC servometers based on numerical analyses
Authors: Itoh Hisayasu 
Published: July 2007

AbstractFor the purpose of miniaturization of DC servomotors with slotted armatures of the side‐leg type, a numerical analysis is made, taking into account magnetic circuit configurations and materials i;the magnetization characteristics of each section are obtained and the optimum circuit design conditions are specified.For a side‐leg type structure using the rare‐earth magnet, the numerical analysis is made using the difference method and the circuit is divided into main and leakage portions. The design approach is to deal first with the main circuit, in which magnetic saturation is considered, and then to consider the leakage circuit, with the operating points of the magnet made equal. The structure as related to leakage permeance is specified quantitatively. For the armature tooth section constituting the main circuit is analyzed, considering saturation, and the flux density distribution together with the magnetic potential drops as the air‐gap flux increases, are obtained for each section. Based upon these analytical results, the optimum circuit design conditions to yield the maximum power rate‐to‐weight ratio are demonstrated and the relation between material and performance limitations are given.
General expressions for attenuation‐characteristics of submarine coaxial cables at high frequency
Authors: Ashiya Fumihiro , Furukawa Shin‐Ichi , Negishi Yukiyasu , Kojima Nobuya 
Published: July 2007

AbstractAn expression for the attenuation loss of submarine coaxial cable systems must provide a precisely calculated attenuation loss at any frequency in the environments of temperature T and water pressure P. The expression, based on the cable loss characteristics measured at atmospheric pressure on land, must yield an accurate estimate of the cable loss characteristics at the sea bottom.Here, we propose a general expression for the attenuation as a function of f, T and P. The expression is based on some material characteristics and sizes, which are the basic parameters defining the transmission characteristics of a submarine coaxial cable. Owing to the introduction of a polynominal representation for the dielectric loss characteristic tan δ which has hitherto not been taken into account, we were able to derive an expression for the attenuation vs. temperature and water‐pressures and to demonstrate explicitly that variations in attenuation caused by temperature and water pressure changes can take the form of polynominal equations in f, T and P. Further, we shall introduce a finite‐order, simple and practical polynominal formula as. an expression for the case when some limitations are allowed on the frequency and on the accuracy of calculating the attenuation.
Fast and accurate electron‐beam deflection circuits using two kinds of D‐A converters
Authors: Wada Yoshifusa , Migitaka Masatoshi , Hisamoto Yasuhide , Mizukami Koichiro 
Published: July 2007

AbstractThis paper presents results of the investigation on the characteristics of the electron‐beam deflection circuit which utilizes a fast D‐A converter and a high‐resolution D‐A converter. The scanning rate depends on glitches of the fast D‐A converter. The setting time calculated by the first‐order approximation model agrees well with the measured result. If the newly proposed deglitching circuit was used, the glitches were reduced to below 10% and the settling time for ±0.0004% was 0.7 μs. The deflection signal stability depends on the high‐resolution D‐A converter. The short‐term stability was ±1 ppm/10 hours without temperature compensation. The long‐term stability with temperature compensation was ±3 ppm/1 month.
Decision method of expansion coefficients for finite fourier series by partial sampling values
Authors: Iijima Taizo 
Published: July 2007

AbstractAccording to the well‐known sampling theorem, expansion coefficients of a finite Fourier series can be determined from a properly selected finite linear sum of all sampling values which correspond to equally spaced division points in the entire interval of the period. In this paper, the sampling theorem is extended to the case where sampling points under consideration do not necessarily spread out on the entire interval. The first half of this paper considers the case where the sampling point interval is equal to an inverse of integer multiple of the period. The second half considers the more general case and general solutions for the successive extrapolation method are derived in a linear recursive form. This method enables one to calculate frequency components from the waveform which was observed successively at constant pitch.
Restoration of gaussian images by two‐dimensional maximum a posteriori estimation
Authors: Akashi Akira , Mizoguchi Riichiro , Yanagida Masuzo , Kakusho Osamu 
Published: July 2007

AbstractThis paper considers the restoration problem for images degraded by superposition of normalized white noise, under the assumption that the discrete sampled signal of the image is a two‐dimensional stationary stochastic process, and discusses a new method of restoring images obtained by extending the maximum a posteriori estimation to the two‐dimensional case.The image signal has essentially a two‐dimensional nature and in that sense a comprehensive approach based on a two‐dimensional image model is more suited to the image restoration than recursive processing based on a one‐dimensional image model. From such a viewpoint, this paper first extends the maximum a posteriori estimation to the two‐dimensional case based on the two‐dimensional image model for the purpose of image smoothing. Then, it is shown that the system of equations for the estimation obtained by the proposed estimation method can be represented by a matrix equation, regarding the image as a matrix. It is also shown that the smoothing estimation for the image is obtained as a solution matrix by a simultaneous processing by matrix manipulation. Lastly, computer simulation is presented, indicating the effectiveness of the proposed method.
Instability and fluctuation in the Hodgkin‐Huxley model axon
Authors: Harada Kouhei , Hirakawa Kazuyoshi 
Published: July 2007

AbstractThe analysis is made for hard‐mode instability in the Hodgkin‐Huxley model (H‐H model) axon and fluctuations near instability points under the current‐clamp condition. When stimulating currents reach 9.8 μA/cm2, the steady‐state solutions of the Hodgkin‐Huxley equation become unstable and stable limit cycles appear. The fluctuation at a certain frequency is greatly enhanced near instability points due to an increase of irreversible circulation of the fluctuation. The membrane impedance shows a sharp peak in this region. In the H‐H model, circulation equilibrium is maintained below instability points. For I = 9.8 μA/cm2, hard‐mode instability occurs due to increasing fluctuation of a certain oscillation mode caused by sharp frequency responses of the system. This result can explain qualitatively the critical slowing‐down phenomenon and a sharp peak in fluctuation spectrum observed experimentally.
A design method of circularly polarized rectangular microstrip antenna by one‐point feed
Authors: Haneishi Misao , Yoshida Shinichiro 
Published: July 2007

AbstractThis paper describes a method for designing backfeed‐type one‐point fed circularly polarized antennas. These antennas are fed at one point from the back side of the substrate and have degeneracy‐resolving segments. Characteristics of the rectangular microstrip antennas with degeneracy‐resolving segments are obtained by means of a variational method. The equivalent circuit at and near the resonance with perturbations is obtained and the condition for circularly polarized antennas is found from both theoretical and experimental viewpoints. Configurations and radiation characteristics of these antennas are discussed and it is shown that these antennas can be used as array elements.
Broad‐band guided‐wave light intensity modulator
Authors: Izutsu Masayuki , Sueta Tadashi 
Published: July 2007

AbstractWith a view to realizing a broadband guided‐wave light intensity modulator, we fabricated a traveling‐wave type guided‐wave light intensity modulator. We succeeded in experiments of light intensity modulation over 18 GHz. In this paper, the traveling wave operation is shown to be superior almost always to the conventional lumped element operation in terms of bandwidth and efficiency. As an electric circuit appropriate for the traveling wave operation, the effectiveness of nonsymmetric electrodes is described. Analytical results are shown for the transmission line constants and modulation frequency characteristics. Next, the push‐pull optical modulation which is useful to obtain an efficient optical intensity modulator with good optical characteristics is considered.The configuration for the optical circuit is studied and the possibility of obtaining a traveling wave operation is discussed. Further, the result of the prototype development and modulation experiment using a Ti diffused LiNbO3 optical waveguide (c plate) is reported. The device consists of two branches made of a single transverse mode waveguide 5 μm wide, and a differential modulation portion with parallel waveguides. The electrodes are nonsymmetric transmission lines with separation 32 μm, width 20 μm and length 6 mm. The half wavelength voltage was 8.8 V, extinction ratio 98%, 1/√2 bandwidth 11.2 GHz and the modulation input power 130 mW for 88% intensity modulation. The modulation sensitivity was 11.3 μW/MHz, and the frequency characteristics were found to be excellent.