bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of voltage transfer function matrix with active RC network
Authors: Hisanaga Kiminori , Takahashi Shin‐Ichi 
Published: July 2007

AbstractThis paper proposes a method of constructing an RC active network to realize a voltage transfer function matrix without using an integrator. the method is based on the fact that an m‐input system of multivariable controllable canonical form can be decomposed into m subsystems of controllable canonical form using state feedback and input transformation. the required m‐input p‐output voltage transfer function matrix is constructed using m passive RC networks and (m + p) summers. the network has the following structure. the capacitor edge voltage of the passive RC network is taken out as the state variable, and the state differential equation is realized by the feedback through the input‐side summers. the output equation is realized by the feedforward through the output‐side summers. the feature of the proposed method is that it is applicable to any proper rational transfer function matrix of any size, not only of the square form. Another feature is that the transfer function matrix can be realized with a fewer number of active elements.
An approximation for the auto‐covariance function of the virtual waiting time in an M/G/1 and its applications
Authors: Matsuda Jun 
Published: July 2007

AbstractThis paper proposes R(t), an approximation for the auto‐covariance function of virtual waiting time in an M/G/1. Calculation by R(t) is much easier and faster than the exact formula R(t). By the use of this approximation, not only the computation for arbitrary model becomes possible, but also the computation time can be reduced below 10‐3 time even for the model which can be calculated by the exact formula, such as M/M/1. Comparisons between R(t) and R(t) for several models show that R(t) approximates R(t) closely enough for practical use. We have applied R(t) to the accuracy estimation of waiting time measurement by test calls (test call method) and obtained several important results for waiting time measurement. They are: i) the accuracy is improved as the interval of test calls is set shorter, but is hardly improved even if the interval is set shorter than ten times the mean waiting time (saturation characteristic); ii) better measurement accuracy is obtained by the test call method if the interval of test calls is properly set than by the real call method; and iii) the coefficient of variation of service time distribution greatly affects the measurement accuracy.
X‐ray CCD image sensor with a thick depletion region
Authors: Saito Hirobumi , Watabe Hiroshi 
Published: July 2007

AbstractIn order to obtain an image sensor for X‐rays with long absorption length and energies greater than 1 ± 2 keV, a CCD with a thick depletion region has been investigated. A thick depletion region can be obtained by using a semiconductor substrate having high purity (high resistivity) and by applying a high gate voltage. However, it is not easy to apply a high voltage since the gate voltage in a CCD is a high‐speed clock pulse for charge transfer. This paper proposes a mode (dc bias‐voltage mode) in which a DC bias voltage is superimposed, keeping the charge‐transfer clock pulse voltage low. the conditions of SCCD and BCCD device parameters are investigated in order to determine useful ranges of these parameters for normal operation and for preventing dielectric breakdown. It is shown that when a substrate with usual purity (doping density 1020 m3) has an applied dc bias voltage of about 300 V, a depletion region with thickness of about 60m can be obtained. the effectiveness of the dc bias voltage mode is confirmed. When CCD characteristics other than depletion region thickness and simplicity of device structure are considered, a BCCD with the frame transfer system is suitable for X‐ray image sensors.
A new fourier descriptor applicable to open curves
Authors: Uesaka Yoshinori 
Published: July 2007

AbstractFourier descriptors are known to be used for describing planner curves in frequency domain. the traditional Fourier descriptors proposed by Zahn and Roskies, and Granlund have the following disadvantages: 1° it is difficult to apply them to open curves; and 2° the end‐points of a reproduced curve from the low‐frequency part of the descriptors do not necessarily coincide with the end‐points of an original curve. the present paper proposes a new Fourier descriptor that does not have these disadvantages and is obtained by expanding in Fourier series the complex‐valued exponential function of the total curvature function of a curve. the proposed descriptor is applicable not only to closed curves but also to open curves, and the end‐points of its reproduced curve always coincide with those of the original curve. the descriptor is invariant under the translation and dilation of a curve. the descriptor of a rotated or reflected curve has simple relations to that of the original curve. Furthermore, the reproduced curve from the low‐frequency part is a good approximation to the original curve in visual sense, and so the information of pattern classes concentrates in its low‐frequency part. In this sense, the proposed descriptor may be used to good advantage in pattern recognition. the abovementioned was verified theoretically and/or experimentally.
Performances of switched diversity for mobile radio systems in rayleigh fading environment
Authors: Imamura Kenji , Hattori Takeshi 
Published: July 2007

AbstractIn the signal transmission of land mobile communication, the received electric field is affected by multipath fading due to multipath propagation, and the transmission quality is degraded. A diversity reception of some type can be an effective technique against this fading. This paper analyzes theoretically the improvement possible using two‐branch switched diversity against the cochannel interference and thermal noise when voice signals are processed by compander and are transmitted by PM. When the baseband SNR (signal‐to‐noise ratio) under fading is 15 dB, the improvement effects against thermal noise and cochannel interference are 9 dB and 4.5 dB, respectively. When the SNR is 10 dB, they are 7 dB and 3 dB. Furthermore, we show that the optimum switching level maximizing the baseband SNR exists and depends on CNR (average carrier‐to‐noise ratio), CIR (average carrier‐to‐interference ratio), and the modulation level.
Reflection characteristics of twisted component in rectangular waveguides
Authors: Yabe Hatsuo , Nishio Kazunori , Mushiake Yasuto 
Published: July 2007

AbstractTo develop a design theory for rectangular twisted waveguide components, the reflection characteristics at the junction to a straight waveguide are studied theoretically. First, a perturbation method and a modal analysis are applied to the hybrid mode field inside the twisted waveguide. In addition to the terms of the second perturbation for the twist constant, we derived analytical expressions for the reflection coefficient and the normalized admittance at the junction. It was found that the reflected wave caused by the higher‐order mode components generated at the junction is equivalent to that caused by the capacitive susceptance inserted in parallel in the transmission line. Also, the difference in the phase constant between the straight and twisted waveguides is due to discontinuity in the characteristic impedance. Next, a theoretical formula containing the effect of multiple reflection has been derived for the overall VSWR of the twisted component inserted in a straight waveguide. the validity of this formula has been confirmed by experiments in the 10‐ GHz band with specially manufactured twisted waveguides. Further, a design chart for a practical 90‐degree twist has been presented and a design method has been given for a broadband transmission characteristic with restricted maximum VSWR values.
Modelling of hot‐carrier effects in small‐geometry MOSFETs
Authors: Wada Masashi , Iizuka Hisakazu , Shibata Tadashi , Dang Ryo 
Published: July 2007

AbstractThe generation of hot carriers in MOS transistors greatly obstructs their microminiaturization, since this effect becomes more serious in a smaller geometry which creates higher internal electric fields. A two‐dimensional simulator of MOSFET has been developed by the authors which includes the generation of hot carriers. the model used takes account of the motion of electrons injected in the gate oxide film. By using this simulator, the device characteristics with an applied voltage stress can be predicted. the simulator has made possible the accurate calculation of the dependency of the gate current on the gate voltage, which could not be solved by conventional simple models. By using this simulator, it is also possible to obtain directly the change of the device characteristics due to the capturing of electrons in the oxide film which is the cause of the channel current, since their distribution now can be obtained. the calculated values of the prediction of the channel current are in good agreement with values obtained experimentally. This simulator is considered to be a useful tool for solving hot‐carrier problems in small‐geometry MOSFETs.
Spread spectrum synchronizing loop for spreading code modulated by code shift keying
Authors: Yoshida Tadayoshi , Nakagawa Masao 
Published: July 2007

AbstractSequence Inversion Keying (SIK) which inverts the signs of the spreading codes, has been used mainly for conventional Spread Spectrum (SS) modulation. Since SIK modulation is essentially not suited to multilevel transmission which enables us to decrease inter‐channel interference, the inter‐channel interference begins increasing significantly if we try to improve the interference characteristic or the multiplexing capability. to improve the performance of the SS, code shift keying (CSK), which is a kind of multilevel modulation, of the spreading code has been proposed recently. However, there have been no reports of a synchronous technique for CSK at the receiver. This paper proposes two types of new synchronizing loops for CSK of SS and their performances are evaluated through experiments. the loops for a 2‐phase and 4‐phase CSKs are treated in the experiments. Both show good synchronizing characteristics and the synchronizing loops which show little performance deterioration despite the increase in the number of phases, are obtained. the proposed schemes compare favorably with the conventional SIK synchronizing loops and give practically sufficient results.
Improving the accuracy and error analysis in floating‐point FFT computation
Authors: Honma Hitoshi , Sagawa Masahiko 
Published: July 2007

AbstractThe cause of the error in the FFT is due mostly to the quantization error of the input data, the round‐off error in arithmetic operation, and the computation error of Wnk= exp (‐j 2nk /N). of these, the error of Wnk is complex, and this error is approximated in the reported error analysis by the truncation error by finite bits. This paper examines the actual computation error of Wnk and its effect. As a result, it is shown that the computation error of Wnk is much larger than the truncation error by the finite bits, and can produce instability in the algorithm. Then to solve the problem, this paper proposes a method to improve the computation accuracy of Wnk. the proposed method can be executed without increasing greatly the processing time and the memory, compared with the direct FFT computation. By using the proposed processing, the error analysis is made more reliable than in the past and the error accompanying the FFT is reduced. Finally, the effectiveness of the proposed method is verified by several examples.
Measurement of contact resistance of electric contacts using SQUID galvanometer
Authors: Minowa Isao , Kanno Makoto 
Published: July 2007

AbstractSQUID (Superconducting Quantum Interference Device) is a very powerful tool in the measurement of very small current, voltage, and resistance because it can be used as a high‐sensitivity galvanometer with zero internal resistance. Since the contact resistance of electric contacts of good quality switches or connectors is low in the milliohm range, it cannot be measured without flowing a current in the range of more than milliamperes in the conventional measuring method. Accordingly, so far, no measured data exist in the very small current region below these values and it is not known whether or not the contact resistance will change in the very small current region in the switches or connectors used in the circuits used for very small signals. In this research, the very small current region of nanoamperes and very small voltage region of picovolts can be measured by using a SQUID galvanometer. In the typical examples of measured results obtained so far the contact resistance of new connectors showed a constant resistance independent of the magnitude and direction of the current in almost all cases.
Generation of musical tones in PARCOR speech synthesizer
Authors: Hibino Masahiro 
Published: July 2007

AbstractThis paper discusses a method in which the impulse response of the digital filter in PARCOR speech synthesizer is used as a musical tone. the following items are discussed. (1) Creation of musical tone‐scale by pole frequency of digital filter. (2) the effect of operational accuracy on the quality of a musical tone, which is an important factor in determining the size of the circuit. (3) Improvement of the quality of the musical tone. For the present circuit size where the word length of k‐parameters is 10 bits and the operational bit length is 14, the sinusoidal wave above C4 has the sufficiently accurate pitch frequency, and there is no problem in creating the musical tone scale. However, it was seen that the impulse response is attenuated in a short period, and a musical tone with practicable envelope characteristics cannot be obtained. As a method to solve this difficulty, a method is proposed whereby the lower bits are rounded‐up in the multiplier output of the filter circuit. the effectiveness of the proposed method has been verified. By this scheme, a PARCOR speech synthesis LSI has been realized which can generate sinusoidal waves of various kinds of envelopes as well as musical tones.
Noise suppression signal processing using 2‐point received signals
Authors: Kaneda Yutaka , Tohyama Mikio 
Published: July 2007

AbstractA number of research reports has been presented on the noise suppression signal processings as one of the important technical problems. Although a reduction feeling of the noise level can be obtained by the conventional method using the one‐point received signal, it has been pointed out that the program of improving the articulation is not sufficient. to solve this problem, we propose a noise suppression signal processing method using two‐point received signals. As the first step, the noise suppression method is discussed assuming that the desired signal is uncorrelated to the noise. It is shown that the noise suppression filter, which is the optimum in the sense of least‐mean‐square error, is obtained from the correlation coefficients between the frequency components of the two‐point received signals. Then a method is shown in which the two‐point receiving noise suppression system can be constructed using FET based on the proposed principle. Finally, to verify the effectiveness of the proposed processing, the method is applied to the two‐point received speech under room noise. the articulation tests were performed for the processed and unprocessed speeches. As a result, it was seen that the syllable articulation score could be improved by 4 to 10 percent when the correlation coefficient between the two‐point received signals of the noise is 0.1 or less and that of the speech is 0.9 or more.
High‐rate preparation of Co‐Cr films on continuous tape substrates via a targets‐facing type sputtering method (TFTS‐method)
Authors: Matsuoka Morito , Hoshi Yoichi , Naoe Masahiko , Yamanaka Shun'Ichi 
Published: July 2007

AbstractA target‐facing type sputtering apparatus which can deposit three‐layer films on a long film base continuously, is constructed. Using this apparatus, a Co‐Cr perpendicular magnetic recording medium is formed continuously to obtain the following results.

A Co‐Cr film with deposition rate of more than 0.4 μm/min is obtained with fine structure and good C‐axis orientation.
When the tape substrate is advanced and the Co‐Cr film is deposited continuously, deterioration of the film C‐axis orientation results from oblique incidence of the sputtered particles at the time of initial deposition.
the properties (such as C‐axis orientation and the magnetic characteristics) of initially deposited film dominates the characteristics of film as a whole.
the (111) oriented permalloy film is used as base soft magnetic layer, and the Co‐Cr film is deposited on this film. Orientation of Co‐Cr film is decided by (111) orientation of the permalloy film.
the temperature of the substrate surface during deposition changes greatly according to the substrate thickness and the applied tensile force on the substrate, thereby changing the film magnetic characteristics. the Co‐Cr perpendicular magnetic recording medium with desired magnetic characteristics and good C‐axis orientation can be formed continuously at high speed by controlling the substrate temperature and by suppressing the oblique incidence of the sputtered particles.
Cyclic sequences generated by neuron model
Authors: Wada Mitsuo 
Published: July 2007

AbstractA neuron can be considered as a threshold element with refractory period. In order to arrive at a generalized treatment of several neuron models proposed in the past, this paper considers a certain type of threshold element network model which has, in addition to exponential decay of refractoriness with time, the effect of past excitations included in the exponent. The periodic behavior of such a network is analyzed and the existence condition for arbitrarily assumed periodic sequence and its generation rule are derived. The procedure is closely related to the continued fraction expansion of a rational number and the sequence is uniquely determined from the network dynamics. The entire set of periodic sequences produced by a network can be derived by the proposed procedure. Lastly, the relation between the proposed network model and the analog neuron model is discussed.
Crosstalk attenuation characteristics between shielded balanced pairs
Authors: Tomita Nobuo , Ohmura Makoto , Koga Hiroaki , Kojima Nobuya 
Published: July 2007

AbstractFuture telecommunication networks will be digitalized and widebanded. The crosstalk between telecommunication lines will be a problem when bilateral signals are transmitted concurrently through a balanced pair cable. A study to suppress this crosstalk is being conducted on a balanced multipair cable with internal shielding for proper units, hereinafter referred to as a shielded balanced pair cable. Theoretical equations are needed to represent the crosstalk attenuation characteristics between shielded balanced pairs for the purpose of designing shield structures for such cable. Hitherto, no equation has been derived pertaining to the amount of crosstalk attenuation between shielded pairs applicable to the design of shield structures.In this paper, shielded balanced pair cables are divided largely into unit‐shielded types and screen‐shielded types. Theoretical equations are derived pertaining to the amount of crosstalk between shielded balanced pairs with consideration of both direct and indirect crosstalk paths. The correspondence to measurements permits design of shield structures by confirming the adequacy of the theoretical equations.In addition, it is established that both direct and indirect crosstalk have dominant frequency ranges considering these frequency characteristics. The electrostatic unbalanced capacitance is also presented for wire shielding within a required amount of crosstalk attenuation.
ϵ‐separating nonlinear digital filter and its applications
Authors: Harashima Hiroshi , Odajima Kaoru , Shishikui Yoshiaki , Miyakawa Hiroshi 
Published: July 2007

AbstractThis paper proposes an ϵ‐separating nonlinear digital filter (called an ϵ‐filter). This filter is intended for effective filtering of low‐amplitude noise superposed on the signal with sharp discontinuities and can be realized by combining a simple nonlinear element with a conventional linear filter. In this paper, the basic ϵ‐filter and its modifications to a trend‐adaptive filter and a two‐dimensional filter are described. The effectiveness of the new filter is demonstrated by computer simulation. Some of its application to EEG analysis, image processing and coding are also presented.
Complementary Schottky transistor logic
Authors: Kaneko Kenji , Okada Yutaka , Okabe Takahiro , Ogura Setsuo , Kudoh Satoshi 
Published: July 2007

AbstractA high‐speed logic circuit, which is compatible on a single chip with I2L (integrated injection logic) and high‐voltage analog circuits is proposed. It is well known that the I2L features low power consumption and high packing density, but that its speed is lower than that of other bipolar circuits. On the other hand, high‐speed bipolar logic circuits consume a lot of power and occupy large area on a silicon chip. This paper proposes a new logic circuit which fills the gap in speed and density between the high‐speed bipolar and I2L circuits and reports the results of experiment. The new logic circuit uses a pnp transistor as a load device and a Schottky‐clamped npn transistor as a driver. An experimental circuit fabricated using an analog‐compatible technology showed a minimum delay time of 1.5 ns and a power‐delay product of 0.5 pJ. A counter circuit was operated at a frequency of 52 MHz.
Characteristics of pitch period and amplitude perturbations in speech of patients with laryngeal cancer
Authors: Kasuya Hideki , Ebihara Satoshi , Chiba Takashi , Konno Tadao 
Published: July 2007

AbstractAs the first step to detect laryngeal cancer by acoustic means (especially cancer of the vocal chords), this paper analyzes the pitch period perturbation quotient (PPQ), pitch amplitude perturbation quotient (APQ) and pitch correlation amplitude (PA) measure, from the outer‐tracheal waves. The results are compared with the result of TNM classification, which is widely used as a clinical classification. The 49 samples were examinees, in which normals were 16 and patients with laryngeal cancer were 15. Among the 15 patients with laryngeal cancer, 14 had cancer of the vocal chords. As the result of analysis, the following conclusions were made. (1) Both PPQ and APQ exhibit correlations with TNM classification, but APQ will be more effective in the detection of cancer of the vocal chords. (2) PA is not very effective in detection at an early stage (T1). (3) Pathologically developed vocal chord cancer (T2) can completely be detected. (4) If allowance is made for 37.5% (6/16) of false positive for the normal, 92.9% (13/14) of the vocal chord cancer can correctly be detected.
Evaluation of SnO2/SiOx/n‐Si solar cells
Authors: Nagatomo Takao , Amano Yuji , Omoto Osamu 
Published: July 2007

AbstractThe insulator interface plays a key role in solar cells with MIS and SIS structures. However, the mechanism of its effect has not been well studied. A simple method of making SnO2/SiOx/n‐Si solar cells by using the spraying method is reported herein. Diode properties of the cells are studied for different values of saturation current density and diffusion potential. Optoelectronic properties of the cells are also investigated as functions of photocurrent density, open‐circuit voltage and fill factor. It is found that SnO2/SiOx/n‐Si solar cells prepared by the spraying method are not diodes of minority‐carrier type and that an increment in open‐circuit voltage has considerable effect on the diode parameters. The diode parameters, device characteristics and open‐circuit voltage vary considerably with the thickness and surface state density of the insulator interface.