bluuebunny/crossref_metadata_2025_split huggingface dataset:
A simplified analysis of ferrite strip
Authors: Araki Kiyomichi , Enjohji Sadao , Naito Yoshiyuki 
Published: July 2007

AbstractPreviously, one of the authors proposed a ferrite strip as a non reciprocal waveguide for millimeter and optical waves. It has many features, e.g., it does not require metal conductors and optical anisotropic material (NbO3), and it generates large field displacement for small anisotropy.This type of waveguide is analyzed by a generalized transmission equation and variational method. These methods, however, are time‐consuming and cumbersome. This paper proposes a simple analysis method using effective permittivity. The field distribution for weakly guiding waves and the radiation characteristics are discussed in detail. It is clear that the occurrence of large field displacement is attributable to weakly guiding waves. The cut‐off condition for the fundamental wave, the condition of edge guide wave generation, the radiation loss and the asymptotic value of the field displacement, are clarified.
Cut‐off mode filter with the structure of metal‐clad optical strip line
Authors: Itoh Masataka , Kudo Masaaki , Mushiakes Yasuto 
Published: July 2007

AbstractThe three‐dimensional mode filter is realized by use of a buffer layer between the metal clad and core of the metal‐clad optical strip line. The equivalent refractive index method is used for analysis of the waveguide transmission properties in which the guide parameters for operation of a TM mode filter and the modal transmission loss are predicted theoretically. With a simple experiment, the dependence of the cut‐off properties on the polarization is confirmed and the correctness of the theory is also verified.
Fabrication and rf surface resistance of superconducting lead cavity by a press forming technique
Authors: Momose Takashi , Akada Katsuhiro , Yamashita Tsutomu , Onodera Yutaka 
Published: July 2007

AbstractThis paper describes fabrication and characteristics of 10‐GHz‐band TM010‐mode superconducting cavities with electroplated lead films on the walls of press‐formed copper shells. The cavity is made up of two symmetrical pieces of copper, and rf current flows parallel to their joint planes. Homogeneous lead films are obtained on copper substrate by using a lead anode with a hemispheric projection. In order to make the rf joints in the cavity, either (a) lead wires were inserted between the copper subtrates with lead films, or (b) indium wires are used between copper substrates on which lead is electroplated. Temperature dependence of Q‐factors of the lead cavities was measured at low temperatures for input power less than 3 mW in an environment where terrestrial magnetism was compensated to be within 20 mG. Q‐factors on the order of 109 were obtained for cavities prepared by the method (b). They also showed residual rf surface resistances as low as 2 × 10‐8ω, which is less than that of TE‐mode lead cavities reported so far for the same frequency range.
Multistage selective dpcm
Authors: Enomot Hajime , Nitta Katsumi 
Published: July 2007

AbstractThe DPCM, a representative prediction encoding system of picture signals, produces two conflicting noises‐overload and granular. This paper describes the selective DPCM that separates picture signals into edge and slant components, and an optimum encoding is applied for each component to consider the two noises. First, statistical analyses on picture signals conclude that they are composed of the edge component and slant component. Second, the edge component, which shows frames of pictures, is approximated by step waves and the slant component, which shows the smoothness of pictures, is approximated by delta modulation. A new method is proposed here: a statistic adaptation in each block and a constant speed scanning are applied for input picture signals. Finally, it is demonstrated that computer simulations prove the usefulness of the method.
A communication network design with the measure of traffic abnormality
Authors: Murata Hatsuho , Akiyama Minoru 
Published: July 2007

AbstractAs the demand for calls by subscribers in communication networks increases, it is necessary to have sufficient equipment or a high‐degree of control over the communication network to make immediate connection of the calls to the desired parties by subscribers at any time they desire. However, economically, it is impossible in large‐scale, modern communication networks to provide enough equipment for all traffic fluctuations. In this paper, a measure of “abnormality” representing the degree of the fluctuations of the subscribers' demand is used to ensure the connection of the calls by limiting all traffic fluctuations below a specified abnormality. First, for the traffic pattern representing the subscribers' demand, we derive a theoretical formula and an approximate calculation method for the traffic intensity which the communication network must actually carry, taking into consideration the number of subscribers.Then we calculate the traffic intensity which each equipment must carry in a communication network using a relatively simple method of route selection. We present a method for obtaining a maximum value for the traffic pattern below a specified abnormality. It is adequate enough to provide a sufficient number of equipment for the traffic intensity to be carried. It may be possible by this design method to have a very efficient reinforcement of the equipment for traffic fluctuations by a limited equipment investment.
Constant‐resistance phase equalizers using directional couplers
Authors: Ohue Kenji 
Published: July 2007

AbstractIn realizing high‐efficiency, high‐speed digital transmission systems, waveform distortion due to amplitude and phase distortion is a definite impediment. This paper proposes a phase equalizer using a constant‐resistance stripline directional coupler as its basic circuit. Unlike phase equalizers realized with lumped inductors and capacitors, the proposed equalizer offers excellent frequency response over a range from DC to 1 GHz. It is shown that the equalizer is equivalent to a transversal filter realizable in the time domain, which simplifies its structure. Experimental results are shown to match the theoretical results using a prototype equalizer implemented with thin‐film hybrid ICs.
Stimulated raman scattering by a relativistic electron beam—analysis of a free electron laser
Authors: Shiozawa Toshiyuki 
Published: July 2007

AbstractThis paper investigates a free electron laser using stimulated electromagnetic wave scattering, i.e., stimulated Raman scattering by the electron plasma (negative energy) wave excited in a relativistic electron beam. Rigorous analysis of its oscillation property is given. Special attention has been given to the output power saturation with decreasing pump power and the energy relations. For simplicity, a one‐dimensional relativistic electron beam is considered and a strong plane EM wave (pump wave) impinging on the electron beam from the opposite direction is assumed. First, Maxwell's equations, the relativistic motion equation for the electron, and the continuum equation for the beam are used. Oscillatory components up to the second order are considered. The mode‐coupling equations for the pump, scattered and the electron plasma (negative energy) waves are derived and rigorous solutions are sought. Energy relations involving these three waves are formulated. Due to the effect of the pump wave, energy is found to transfer from the electron beam to the scattered wave and the manner in which the scattered wave grows gradually is clarified quantitatively.
A high sensitive speech detector based on sign bit sequence manipulations
Authors: Yatsuzuka Yohtaro 
Published: July 2007

AbstractIn a speech signal transmission by means of the pause of speech such as the DSI, the speech detection capability is significant and accurate detection of it is indispensable. This paper proposes a detector for operations in each block with improved detection characteristic realizing a shortened hangover time and a high sensitivity. These results are obtained based on the sign bit sequence matrix processing in terms of the short‐time energy, the zero crossing rate and the sign bit sequence of the input signal. Especially in processing the sign bit sequence matrix, a degree of the speech spectrum concentration is investigated by processing the sign bit sequence of the original signal as well as the obtained signal through the pre‐emphasis filter, and the sign bit sequence matrix composed of the sign bit sequence of the fundamental frequency and its harmonic sine and cosine waves. A computer simulation has indicated that a speech level of above ‐51 dB m is detected effectively without any degradation of speech quality. The average activity of speech in an international long‐distance line is reduced remarkably to 36% compared with the conventional one of 40%, and the average talkspurt is shortened to 436 ms which is half that of the conventional ones. Furthermore, it is shown that the detector has an excellent discrimination characteristic for thermal noise.
Considerations on structure of single‐channel counting encoder having μ‐255 companding
Authors: Sasakawa Masa‐Aki , Takas Masahiro 
Published: July 2007

AbstractOwing to their economy and flexibility, much attention is devoted to single‐channel encoders based on LSI technologies. Various circuit configurations have been proposed. This paper presents a systematic discussion of the types of circuit configuratious with a view to applying a counting encoder with lower element accuracy to a single‐channel encoder. Initially, we propose various circuit configurations types for companding encoding by controlling the pulse width of the counting clock at the power of two. We then classify the counting encoder with regard to the processing pattern of encoding, clarify the relationship between the element accuracy and performance deterioration and describe the circuit type adopted for using LSI. The application conditions for digital networks are examined and a simple method is proposed which permits synchronization of the PCM output signal to the zeroth group even if the counting clock and the zeroth group are functioning asynchronously. In addition, we propose a method of adjusting the levels of analog input signals as appropriate for the counting encoder. It is expected that the above discussions will provide the optimum composition of the single‐channel counting encoder.
Narrow‐bandwidth multichannel system for television fm signal
Authors: Sakata Haruo 
Published: July 2007

AbstractA new transmission system is proposed in which the television signal is used as the modulation signal and the wideband FM signal with low modulation index is transmitted through a multichannel narrow‐bandwidth transmission path. The signal processing of this system is as follows:

Carrier frequency of broadband FM signal is made equivalent to the sum of the maximum carrier frequency of the modulation signal and half the frequency deviation by using a frequency converter.
Frequency is divided by N by flip‐flop and the signal is transmitted as N channels narrow bandwidth FM signal. The phase difference between each of the channel carrier frequencies is π/N radian.
In the receiver, the broadband FM signal is reformed by an exclusive‐OR circuit after the wave is shaped by the limiter.
This paper analyzes the above‐proposed FM signal and estimates the change of frequency spectrum. Furthermore, it has been confirmed experimentally using the television signal that the output of the 30 MHz and FM modulator having 14 MHz bandwidth (base band of modulation signal is about 5 MHz) can be transmitted through the 4 channels having 3.6 MHz bandwidth.
Is(z) transformation and implementation problems of digital systems designed by is(z) translation
Authors: Sakaguchi Hiromi 
Published: July 2007

AbstractThe Is(z) transformation is essentially nonlinear transformation and has been used widely because of its wide linear range. There were two problems to be solved regarding the implementation of the digital systems: (1) to simplify the stabilizing procedure associated with this transformation; and (2) to improve the accuracy in implementing the digital system due to limited word length. For (1), the synthesis of z functions by pole substitution is adopted to simplify the procedure. For (2), the algorithm is modified to improve the accuracy. Further, the accuracy in implementing the digital systems with different word lengths and filter structures is evaluated in terms of the error rate in locating the poles which are estimated by the linear prediction method.
Reflection of a Gaussian beam at oblique incidence on a stratified dielectric medium
Authors: Tanaka Mitsuru , Saga Nobuhiro , Fukumitsus Otozo 
Published: July 2007

AbstractThe reflected and transmitted fields of a Gaussian beam which is incident upon a stratified dielectric medium at oblique angles are expressed in terms of the fundamental beam modes with proper selection of the propagation axis and beam parameters. The reflected field is expanded into the mode function system with the same propagation axis and same beam parameters as the direct reflected beam and the reflected power is calculated from its expansion coefficients. The reflected field and reflected power can be simplified if the stratified medium is symmetric with respect to the intermediate layer. As an example, the output mirror of the YAG laser resonator is considered and the amplitude distribution of the reflected field and reflected power from the seven‐layered medium is calculated. The effect of the minimum spot size of the incident beam and the incidence angle on the reflection characteristics is analyzed.
Polarization transmission characteristics of optical fibers with elliptical cross section
Authors: Fujii Yoichi , Sanos Koichi 
Published: July 2007

AbstractIn the transmission via optical fibers connected to laser diodes, optical switches, optical filters, etc., or in high‐sensitivity high‐selectivity optical heterodyne detection system, polarization characteristics become important in addition to transmission loss and dispersion. The polarization transmission characteristics of optical fibers with elliptic cross‐section are calculated by characteristic matrix method for large values of ellipticity. For two orthogonal polarization modes (oHE11 and eHE11 modes) the transmission velocity, group velocity and their difference (elliptic double refraction) are obtained. The group delay difference among modes is very small but elliptic double refraction greatly affects the polarization characteristics.
A routing system of single‐layer printed wiring boards
Authors: Futagami Shin , Shirakawa Isao , Ozakis Hiroshi 
Published: July 2007

AbstractA great part of the layout design of single‐layer printed wiring boards and hybrid IC's is still implemented manually, and hence of practical importance is the layout automation in this field.This paper describes an automatic routing system which can be applied to single‐layer printed wiring boards and hybrid IC's used for numerous analog appliances. This system is distinctive in that the routing process is implemented through a number of stages such that at each stage an interference relation for the from‐to's which remain to be interconnected is sought. Then according to the interference information thus obtained, a maximal set of wire patterns which do not intersect each other is generated. Several experimental results are also shown to reveal how much the system attains its potentialities to be of great use in the practice of layout design for single‐layer printed wiring boards and hybrid IC's.
Thickness aberrations in two‐photon‐resonant image upconverters
Authors: Sasaki Shinya , Mishima Teruhito , Sakurabas Ichiro 
Published: July 2007

AbstractAn image equation for two‐photon‐resonant image upconverters with finite medium thickness is derived by the ray matrix method and the thickness aberration and coma are obtained theoretically. The thickness aberration and coma become small when two pumping sources and an infrared object are located on the same longitudinal plane. These aberrations can be eliminated if locations of two pumping sources and infrared object, the medium thickness and dispersion characteristics satisfy a certain relation. The image equations are analyzed for three different optical systems and their resolutions are compared.
High‐speed digital PLL using trigger oscillators
Authors: Suzuki Shuji , Kurita Taiichiro , Ozawa Shinji , Moris Shinsaku 
Published: July 2007

AbstractThe conventional digital phase‐locked loop (DPLL) cannot be used for high‐frequency purposes, because the local oscillator frequency of the DPLL is several times the input frequency. This paper proposes a use of trigger oscillators to the DPLL. The first‐ and second‐order DPLL's using trigger oscillators can be used if input frequency is as high as the maximum logic clock frequency. The quantization noises of the second‐order DPLL using two trigger oscillators are lower than those of the conventional DPLL. The trigger oscillators can be used in any type of DPLL. Its input frequency becomes higher or its quantization noises become lower.
Measurement of lifetime and diffusion constant of minority carriers by phase shift technique in EBIC
Authors: Fuyuki Takahashi , Matsunamis Hiroyuki 
Published: July 2007

AbstractLifetime and diffusion constant of minority carriers in Si have been measured using phase shift technique in EBIC. The phase of EBIC delays in regard to the recombination in materials when the intensity‐modulated electron beam is used in the line scan method of EBIC. The phase shift between the excitation source and the EBIC is calculated theoretically by solving the three‐dimensional time‐dependent diffusion equation. The phase shift increases linearly with the scanning distance. The phase shift against the distance is a function of lifetime and is not influenced by surface recombination. From the values of the phase shift and the diffusion length, the lifetime and the diffusion constant are determined simultaneously. Experimental results in Si Schottky diodes showed good agreement with the theory.
Length dependence of baseband bandwidth for spliced graded‐index multimode fibers
Authors: Tanifuji Tadatoshi , Horiguchi Tuneo , Tokuda Masamitsu 
Published: July 2007

AbstractIt is important in determining system configuration to understand the length dependence of the baseband bandwidth of a graded‐index fiber. An actual fiber communication system is constructed from a number of connected fibers with different characteristics. In such cases, the length dependence of the baseband bandwidth becomes very complex due to mode conversion and mode dispersion compensation at the junction and no practical method exists to estimate the characteristics. Therefore, actual systems are approximated by setting an appropriate value of γ in the γth power expression. This paper first finds the length dependence (γ value) of the baseband bandwidth measured in a number of fiber systems actually installed. Next, to analyze factors determining the length dependence, experimental and theoretical investigations are conducted. It is found that an important factor determining junction characteristics is the mode dispersion compensation regulated by the group delay difference among principal mode groups as well as within a principal mode group. It is also found that mode conversion at the junction has a negligible effect. In an actual communication channel employing many fibers, correlation in the group delay difference among the principal mode groups and within the principal mode group of each fiber becomes small and the value of γ is restricted. In practice, it is possible to estimate the average baseband bandwidth by setting γ ∼ 0.6.
Preparation of permalloy films using facing‐type targets and a high‐rate and low‐temperature sputtering method
Authors: Hoshi Youichi , Kojima Masaya , Naoe Masahiko , Yamanaka Shun‐Ichi 
Published: July 2007

AbstractPermalloys are promising as candidates for a thin‐film head and as a material for the soft substrate magnetic layer using normal magnetic memory media. Permalloy films prepared using facing‐type targets and a high‐rate and low‐temperature sputtering process are examined. As a result in the facing‐type target sputtering method, it is desirable to use double targets with a structure consisting of a small satellite target positioned eccentrically inside the mother target.The morphology and magnetic properties of sputtered films depend strongly on the substrate bias voltage. To obtain a good magnetic film, a substrate bias voltage in the range of ‐120 to ‐150 V and/or a substrate temperature of 350 C is needed. In particular, with the application of bias voltage, in addition to being stress free at low substrate temperature, a thermally stable film is also obtained. It is observed that adhesion of the film to the substrate can be improved by sputter‐cleaning of the substrate before deposition. Perpendicular anisotropy of the films decreases significantly and the magnetic properties of the films improve with increasing substrate bias voltage and substrate temperature. This is probably attributable to the change in film morphology.
On some design examples of a circularly polarized wave array antenna using slot antenna combined with parasitically excited dipoles
Authors: Itoh Kiyohiko , Shinada Hidetoshi , Ariga Toru 
Published: July 2007

AbstractThere are two methods to obtain a circularly polarized array antenna. One is to arrange and feed linearly polarized elements (such as slots) in an appropriate manner. Another is to arrange circularly polarized elements. The second approach is used to design a four‐element circularly‐polarized planar array consisting of a slot and parasitic dipoles. An array antenna having good characteristics is obtained and described. In general, coupling exists between the array elements, and these couplings affect the antenna characteristics, particularly in the case of circularly‐polarized arrays. Before beginning the design, the changes in the circular polarization characteristics of a single element are numerically evaluated as a function of the coupling, and this information is used as a reference in the design of the circularly polarized arrays. Then, with a formulation including the inter‐element coupling, calculations are made for a situation more nearly approximating actual practice. The possibility of obtaining a small antenna with a bandwidth of 1.5 dB axial ratio (6%) and a gain of more than 13 dB is pointed out.
Spread spectrum communication with white gaussian noise
Authors: Takada Kazuhiro , Naito Sachio , Masuda Takao 
Published: July 2007

AbstractOne of the basic problems in the Spread Spectrum Multiple Access (SSMA) system is interchannel interference noise. Noise is an important determinant of the possible number of system characteristics of the SSMA system using White Gaussian Noise (WGN) for the spreading signal. The ratio of signal to interchannel interference noise (S/Ni) obtained herein can be the theoretical upper bound for direct sequence SSMA systems.This paper also proposes a new SSMA system in which the delayed WGN and the spread information signal are transmitted together. The system has no synchronizing problem between spreading and despreading signals. Therefore, receiver structure can be very simple.