bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the tap weight fluctuation in zero forcing automatic equalizer
Authors: Sakurai Masaru , Murakami Junzo 
Published: July 2007

AbstractLong‐term instability is one of many serious problems in Zero‐Forcing (ZF) automatic equalizers for television signals. This paper analyses this problem by solving the tap weight covariance matrix. the result is that the tap weight fluctuation (variance) increases significantly as the input signal bandwidth becomes narrow and/or the number of taps increases. the leakage algorithm which is very effective in reducing the tap weight variance is examined also. In addition, the timing adjustment which is another problem in the ZF algorithm, is examined and it is proved that the leakage algorithm does not improve the instability caused by timing misadjustment.
1/f frequency fluctuations of a quartz oscillator and temperature fluctuations
Authors: Noguchi Yasuaki , Teramachi Yasuaki , Musha Toshimitsu 
Published: July 2007

AbstractWe have investigated correlations between an ambient temperature and a frequency of a 5‐MHz, 5th overtone IC‐cut plano‐convex quartz oscillator. We found that the spectral density of frequency fluctuations is composed of three parts over a fluctuation frequency from 10−6 to 10−2 Hz; in the lowest frequency part it is proportional to 1/f2, which continues to 1/f and eventually to f0. the 1/f2 and f0 spectra are caused by ambient temperature fluctuations. Thus we have found that the 1/f spectrum has nothing to do with temperature fluctuations, which, therefore, provides a limit for frequency stability of a quartz oscillator.
A new way of generating the nyquist spectral‐shaped high‐speed and multilevel digital signals
Authors: Saito Yoichi , Matsue Hideaki , Komaki Shozo 
Published: July 2007

AbstractHigh‐speed waveform transmission is of great importance in the realization of digital radio systems with high spectrum utilization efficiency. the binary transversal filter (BTF) offers an effective technique for achieving high‐precision waveform generation because it is a means of producing the desired waveform directly in the time domain. This paper presents a new technique for design of the BTF and discusses the authors' experimental results. the new BTF can be applied quite easily to high‐speed multilevel signals and is composed of a shift register, a programmable ROM (PROM) and a D/A converter which are driven by a multiphase clock. A was used to design the basic parameters of the BTF: sampling frequency, number of taps and tap coefficients, quantization levels for the D/A converter and allowable phase error for the clock signal. an analysis was conducted to determine the effect that each factor has the spectral characteristics and intersymbol interference characteristics. Further it was shown that based on this configuration and design method, a 12.5‐MB 4‐level Nyquist waveform can be realized without adjustment.
Nonlinear interaction of surface acoustic waves in waveguide
Authors: Nakagawa Yasuhiko , Ono Mitsuhiro 
Published: July 2007

AbstractA theoretical and experimental study has been conducted on the nonlinear interaction of a surface acoustic wave (SAW) on a surface acoustic waveguide. It is shown theoretically and experimentally that from the parametric mixing phenomenon of two SAW's traveling in the opposite directions, a SAW with the sum frequency is generated which propagates with a certain angle from the waveguide. By changing the frequency difference, the propagation direction of the sum frequency SAW can be controlled freely. the excitation efficiency is such that: (1) it is higher for a narrow waveguide and for a larger velocity variation; and (2) it is periodic with respect to the waveguide width and the period is one wavelength of the sum frequency SAW. Such a generation of the sum frequency SAW and the SAW beam scanning in a plane are possible only with the SAW guided mode. Since the control of the SAW propagation direction in a plane is possible, an application to a two‐dimensional signal processing is conceivable.
Carry time of magnetically coupled Josephson adder circuits
Authors: Yamada Hajime , Ichimiya Yoshichika , Ishida Akira 
Published: July 2007

AbstractA carry circuit for Josephson adder has been studied and tested experimentally. For carry calculation, a ripple carry process by asymmetrical interferometric majority gates is employed because it can reduce the gate number‐add time products compared with carry look ahead process by conventional OR‐AND gates. Add time measurement has been performed with these carry circuits connected to dummy sum circuits. Operation speed as fast as 740 ps was obtained for 16‐bit calculation, which shows excellent agreement with computer simulation. By the analysis, it has been clarified that the operation speed is limited by impedance mismatched input lines.
A synthesis method for the wideband variable equalizers
Authors: Kawakami Atsushi , Matsuda Tsukasa , Takahashi Shin‐Ichi 
Published: July 2007

AbstractApproximated transfer functions are developed for variable equalizers to compensate for wideband signal attenuation distortion or for large attenuation distortion in the relative variation width of amplitude characteristics in communication systems. A method is presented for approximately expressing a variable transmission characteristic in the form of a 2‐variable minimum realizable rational transfer function which contains only variable parameters in the denominator. Next, actual approximated transfer functions are given for several specified equalization bands, equalization variable bands for variable parameters and various network orders. Analysis is made of the equalization errors of those variable transfer functions, verifying the effectiveness of this technique.
Design of plant expansion in subscriber optical fiber cable network
Authors: Yamamoto Hideo , Yamamoto Yoshikazu 
Published: July 2007

AbstractThis paper considers the low‐cost trends of optical fiber cables and the measures for coping with the widely scattered demands thatare regarded as special features in the initial stage of the formation of a subscriber optical fiber cable network. A method for economical construction of an optical cable network is discussed. First, the low‐cost trends of the optical fiber cables are dynamically grasped and a method is clarified for designing installation intervals and the sizes of the cables which will make the present annual expense worth a minimum by using dynamic programming. Next, for cable construction systems connecting the local office and the plural distribution areas, three systems, the fiber‐reduction system, fiber‐nonreduction system, and independent cable system, are considered and the applicable domains of these systems are clarified from the economical viewpoint with the installation cable size and distribution area as parameters. Moreover, a method is obtained for simultaneous design of the cable construction system which will minimize the total cost, and the distribution area size is shown for a given installation cable size. It is clarified from these results that it is more economical to use a shorter installation interval in the initial stage of the formation of the subscriber optical cable network than the present subscriber cable network using the symmetrical pair cables. Also, it is desirable to set a wide distribution area consolidating two to four present fixed distribution areas.
A decomposition method and acceleration techniques for a fixed point algorithm
Authors: Yamamura Kiyotaka , Oishi Shin'Ichi , Horiuchi Kazuo 
Published: July 2007

AbstractRecently, extensive studies have been carried out on the algorithms which constructively determine the solution of nonlinear equations. These algorithms are in general called fixed‐point algorithms, and their attraction lies in the global convergence. However, fixed‐point algorithms have been a problem in that the execution speed is decreased greatly with the increase of the size of the system of equations to consider. This paper proposes a decomposition method and acceleration techniques as a means to improve the computational efficiency of the fixedpoint algorithms. Kevorkian's method is used in this paper as decomposition. Since the method includes errors in the decomposed equations and function values, it is important to discuss the convergence of the solution algorithm and to improve the convergence speed taking the effect of those errors into consideration. This paper shows a solution algorithm in which the system of equations is decomposed by Kevorkian's method, and then Merrill's method, a typical fixedpoint algorithm, is applied. Accuracy of simplicial approximation and convergence properties of the algorithm are discussed, indicating that the algorithm exhibits local quadratic convergence under some suitable conditions. By numerical examples, it is verified that the algorithm exhibits quadratic convergence. the method is compared with the past methods, indicating the effectiveness of the proposed method.
ARMA digital lattice filter based on a linear prediction theory
Authors: Miyanaga Yoshikazu , Miki Nobuhiro , Nagai Nobuo 
Published: July 2007

AbstractThis paper proposes some elementary sections of an ARMA lattice filter. an ARMA lattice filter with an arbitrary AR order and an arbitrary MA order is presented. A conventional ARMA lattice filter has already been constructed by a method used to develop an AR lattice filter to a 2‐dimensional filter. Therefore the conventional filter is not suitable for a filter realization when an AR order and an MA order differ from each other, and for the design of a minimum realized ARMA model. the most important characteristic of lattice filters is an orthogonality between every prediction error calculated at each elementary section. Employing this characteristic, we employ the AR lattice filter in a speech analysis, synthesis, an equalizer, and so on. It is shown that the proposed ARMA lattice filter satisfies an orthogonality. Furthermore, the ARMA lattice inverse filter which is an analyzer for an observed waveform and the ARMA lattice filter which is a synthesizer for the waveform are presented.
Block interleavers with maximum pulse distance
Authors: Ohue Kenji , Ohtake Kohhei 
Published: July 2007

AbstractIn block interleavers which reorders digits of pulse sequence in a block, pulse distance distribution and interleaving delay time characteristics depend greatly on readin and write‐out methods of block interleaves and the phase relation between observed pulse sequence and an interleaved block. Hence, it has become necessary to choose an interleaving method in accordance with the purpose. So far, little study has been made which takes account of this condition. This paper analyzes (b, q) interleaver by choosing pulse distance and minimum coding delay time as criteria, and shows that effective block interleavers can be classified into four classes. Furthermore, it is shown that some classes include two kinds of new (b, q) block interleavers which make the pulse distance greater than q ‐ 1, and these methods maximize the minimum pulse distance among (b, q) block interleavers. Finally, an application example to smear transmission systems is presented and it is shown that the proposed (b, q) block interleavers make it possible to suppress more greatly the burst impulse noise than the conventional (b, q) block interleavers.
Performance of improved tangent type FM demodulator using digital signal processing
Authors: Hagiwara Masafumi , Nakagawa Masao 
Published: July 2007

AbstractFM demodulators using DSP techniques include the DPLL type, the quadrature type, the tangent type, etc. Compared to their analog counterparts, they are more useful with respect to stability, reliability and convenience of adjustment. However, since the detection characteristics for DPLL or quadrature‐type demodulators are sinusoidal, the introduction of distortion cannot be avoided. In particular, if the input signal is wideband FM, there is a marked deterioration in the characteristics caused by distortion. This paper investigates the tangent‐type FM demodulator whose circuit construction only has in the past been shown and whose characteristics have not been studied at all. It is made clear that the parameter‐setting condition is strictly limited. Next, the detection condition is described and an improved tangent‐type FM demodulator, whose detection characteristics are largely elevated, is represented and its better characteristics are shown. Moreover, comparison is made between this and other types of demodulators by means of simulation, and the effectiveness of this type is shown.
Theoretical study on the coupling of two‐dimensional gaussian beam to a dielectric slab waveguide
Authors: Nishimura Eiichi , Morita Nagayoshi , Kumagai Nobuaki 
Published: July 2007

AbstractMode coupling and reflection of a two‐dimensional Gaussian beam incident on an arbitrarily shaped end‐surface of a slab waveguide are studied theoretically. the relation between the shape of the end‐surface and the coupling efficiency is studied in detail by means of numerous numerical examples. It is found that: (1) the vertical planar end‐surface exhibits the highest coupling efficiency if the incident beam has neither axial shift nor angular shift and if the beam waist position coincides with the end‐surface; (2) an optimum shape for the end‐surface exists that provides the best coupling if the beam waist position is separated from the end surface; and (3) extremely high coupling efficiency is attained if the TM beam wave is incident with a Brewster angle. Although the analysis is based mainly on the integral equation method, a simple method is also presented for computing coupled power from the fields approximately obtained from the Fresnel formula.
Temporal transient response of color mechanism–Broca‐sulzer effect of chromaticness
Authors: Sakata Haruo 
Published: July 2007

AbstractThis paper discusses the temporal transient response of chromaticness, which was measured by the Broca‐Sulzer effect. (1) the Broca‐Sulzer effect of chromaticness was determined for 8 hues centering around the achromatic color light. the transient time to reach a certain level of saturation was shorter for red and cyan, but was longer for yellow and blue. (2) A pattern was constructed which keeps the saturation constant and varies the hue continuously for 360 deg in the vertical direction and varies the presentation time gradually in the horizontal direction. By using the above pattern, the apparent change of the hue was measured. It was verified that cyan and red with fast rise‐time is observed in a wider range in the region of shorter presentation. (3) By the result of those transient observations in color mechanism, it is concluded that, at least near the fovea, the (r ‐ g) axis in the color mechanism is temporarily of wide‐band and the (y ‐ b) axis is of narrow‐band.
Crosstalk characteristics for symmetrical star quad cable with unbalanced terminations
Authors: Tomita Nobuo , Kawaguchi Tokihiro , Ohmura Makoto 
Published: July 2007

AbstractIn subscriber line signalling systems using the telephone network for selective control of specified on‐premises devices, with consideration of the exchange configuration, there are cases when the subscriber channel is used in an unbalanced condition and the channel crosstalk characteristics become a problem. Up to this time, we know of no studies which have considered the effects of subscriber line crosstalk characteristics with unbalanced terminations. In this paper, we first establish models and derive theoretical equations for two categories of line crosstalk‐the first being the case where either the disturbing or the disturbed line has an unbalanced termination, and the second being the case where both lines have unbalanced terminations. Results obtained in the theoretical analysis are verified by experiments. Next, using a theoretical expression considering the relationship between crosstalk coupling and crosstalk attenuation, it is found that, the subscriber in the low‐frequency region where the coupling impedance has no effect, the single‐circuit unbalanced termination gives about the same performance as the balanced termination, whereas the crosstalk attenuation is about 50 dB lower when both circuits have unbalanced terminations: In addition, for the case where both lines have unbalanced determinations, we present a method of specifying the signal frequency and line termination impedance, which are important parameters for the design of the above‐mentioned signalling systems from the standpoint of achieving the desired crosstalk characteristics.
Transient analysis of microstrip gap
Authors: Koike Shoichi , Yoshida Norinobu , Fukai Ichiro 
Published: July 2007

AbstractThe time domain analysis of electromagnetic field is not only of theoretical interest for rigorous analysis of Maxwell's equations in the time domain, but is important in practice for waveform transmission in a recent high‐speed pulse technique. In the waveform transmission, the time variation of the electromagnetic field at the receiving end is important. This variation is the result of accumulated wave phenomena such as reflection, diffraction, and dispersion due to the boundaries and medium distribution in the system. In particular, in the transient such as the rise of the signal waveform, the time history of each wave phenomenon strongly affects the characteristics. the present paper treats a microstrip line with a gap. A three‐dimensional analysis has been performed with the strip thickness and the surrounding free space taken into consideration. It is shown that the wave exhibits a complex variation even at the gap and that it is a well‐known capacitively coupled circuit. This is confirmed in transient state by means of the time variation of the electric field distributions at the underside of the strip, the side surface of the strip, and the gap end surface. to quantify the steady‐state characteristics, the parameters of the even and odd modes of the μ‐equivalent circuit are derived from the three‐dimensional electric field distributions. They are compared with the conventional two‐dimensional static analysis, and the features of the three‐dimensional analysis including the thickness are clarified.
Dielectric measurement by h‐plane dielectric loaded resonator
Authors: Yamanaka Hideo , Farooq Umar 
Published: July 2007

AbstractThis paper describes the measurement of a complex dielectric constant by a resonance method using a rectangular cavity (cross section 3.48 × 1.58 cm2 and length 8.3 cm) filled with two layers of dielectric materials (the upper layer is air). the experiments are performed in the range of 7 GHz and the test materials are methacrylate and polystyrene sheets.
Metal‐migration of aluminum film on SAW resonator
Authors: Ebata Yasuo , Morishita Shigefumi 
Published: July 2007

AbstractThe SAW resonator has been considered as a small‐sized high‐Q resonator in VHF and UHF bands. High‐density energy is therefore stored within the resonator and the study of drive levels is specifically important among reliability. This paper describes the change in performance due to drive levels of the SAW resonator and their cause, mecahnism, and, further, corrective action against the performance degradation. an aluminum film grating reflector with IDT structure formed on an LiTaO3 substrate is used as the SAW resonator for measurement of the aging of electrical characteristics by means of parameters of the drive level. As a result, deterioration due to migration of grain boundary in the aluminum film is observed in a resonator exhibiting performance degradation. Moreover, from a comparison between the distribution of aluminum damaged and stress distribution due to SAW within the resonator, and theoretical estimation of its intensity, the internal stress in the aluminum film induced by the SAW energy causes migration and the stress is about 3.3 × 107 N/m2. to prevent performance degradation from its generation mechanism, we propose a method using copper‐doped aluminum film. From experiment we found that the drive level causing the performance degradation is improved more than 10 times.
Carried traffic estimate errors for delay systems
Authors: Machihara Fumiaki 
Published: July 2007

AbstractThe carried traffic estimate errors for delay system models are analyzed. Particular attention is given to the traffic models for the switching machine control equipment. It is known that the holding time distribution of the switching machine control equipment is one whose coefficient of variation is less than 1 (exponential distribution). Therefore this paper emphasizes the analysis of the effect of the holding time distribution on the estimate errors. First, the carried traffic estimate errors for M/D/S queue and M/M/S queue are analyzed and it is shown that the estimate errors for the M/D/S queue are always smaller than those for the M/M/S queue for any fixed utilization. As a result, it is conjectured that as the coefficients of variations for the holding time distributions increase, the estimate errors also increase. In the latter part, this conjecture is justified for one server model M/G/1 queue. In analyzing the carried traffic estimate errors for M/G/1 queue, the approximation of the busy period distribution by an hyperexponential distribution is proposed, and its estimation accuracy and its applicable range are studied.
Triple hybrid primary power supply system
Authors: Kawamoto Hisanosuke 
Published: July 2007

AbstractVarious proposals have been made in recent years with regard to hybrid power supply systems for communication system applications. the main common feature of such systems is the incorporation of two or more kinds of power sources. In this paper we first discuss the concept of hybrid systems and then describe experimental results obtained with a triple hybrid system incorporating a wind‐power generator, solar cells and Diesel generating equipment. It is then shown that the continuous time distribution of natural energy in the nonenergized state follows an exponential function. We apply a mathematical model which is in good agreement with the experimental results and develop a theory for derivation of the required storage battery capacity as well as the power to be applied by the Diesel generators. Then, applying this design method to various systems, we present a quantitative analysis of the complementary relationship between wind power and solar illumination and show that the triple hybrid system is most economical.
An analysis of wiring performances of a routing system for high density printed wiring boards
Authors: Asahara Shigeo , Odani Masayasu , Ogura Yasunori , Shirakawa Isao , Ozaki Hiroshi 
Published: July 2007

AbstractRecent advances in the technology of microelectronics have changed the design rule for printed wiring boards, allowing the number of wiring tracks between consecutive pins of an ordinary dual in line package (DIP) to be two or more. When the wiring density augments to that extent, conventional routers are confronted with various difficulties.To cope with this situation, the single‐row router which has topological fluidity can be employed in conjunction with the line‐search router. We have already developed a new routing system constructed of a line‐search router combined with a single‐row router and of a maze‐running router. However in each routing process there are many parameters, the combination of whose values have much influence on the wiring performance of the whole system.In this paper we outline this routing system, describe some experimental results in order to determine values of these parameters, and show that the analysis of implemented results suggests high performance for high density printed circuit boards (PWB's).