bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fiber selection in subscriber optical loop
Authors: Member Eiji Maekawa, Regular 
Published: July 2007

AbstractThis paper considers the effect of the fiber selection method on transmission distances in subscriber optical loops. The fiber selection method divides the fibers in an optical line into two groups according to optical losses, and is an effective method since there is no problem of connections, etc., as in the test splice. First, the optical loss improvement effect is investigated in the case where the group with smaller losses is used as a standby fiber for dedicated optical lines of large‐demand subscribers. As a result, it is understood that the optical loss can be reduced considerably with a small number of standby lines. Next, we consider using the group with larger losses to subscribers in short transmission distances, and clarify the grouping method which can serve all the subscribers along the line. Using this and the previous results, it is clarified that the transmission distances in subscriber optical loops can be made longer and the coefficient utilization of fibers can be achieved.
Broadband characteristics of bodies of revolution
Authors: Kawakami Haruo , Sato Gentei , Harada Hisashi 
Published: July 2007

AbstractA monopole antenna consisting of a body of revolution is given by a set of simultaneous equations on the rotationally symmetric surface current of a conductor separated with respect to the variable of the envelope length on the surface of the body of revolution and the variable in the rotating direction. The structure is analyzed in detail by means of an extended moment method based on the present theory.As an application, this analysis is applied to a conical monopole antenna. Studies are performed to find body shapes providing broadband characteristics. It is found that antennas with cross sections approximated by straight lines, ellipses and circles have an impedance of 50 ω over a wide range of frequency. When these shapes are replaced with wire elements for analysis, 16 elements are found sufficient to provide the characteristics for the bodies of revolution. Theoretical calculations and experimental results are compared. Agreement is excellent and the method is found useful.
Piezoelectric ceramic filters using the edge‐mode vibration
Authors: Iseki Yuji , Shimizu Hiroshi , Watanabe Hiroshi 
Published: July 2007

AbstractFor a conventional MF‐band piezoelectric filter, the contour vibration has mainly been used in which the whole of the vibrator body vibrates, and the vibrator is supported at its nodal point by a spring or a soldered wire. This degrades the characteristics of the filters, widens their manufacturing deviations, and limits their reliability and miniaturization. This paper proposes a new type of piezoelectric ceramic filter for the MF‐band using the edge‐mode vibration. This type of filter has a simple shape and a small size, and can be supported by vibration‐absorptive means such as a trapped‐energy type vibrator. The three‐terminal single‐mode filter is presented in which the electrode is divided with a gap into two parts to be used for the input and output. The relationship between the width of the gap and the fractional bandwidth of the filter is calculated theoretically, and the upper limit of its bandwidth is given. By using Pb(Zr, Ti)O3 pieaoelectric ceramics, two types of 455‐kHz filters having the 3‐dB fractional bandwidth of 1.3% and 1.6%, respectively, have been produced experimentally. By connecting 3 or 4 units of either type of the filters in cascade, a filter having the out‐of‐band attenuation greater than 50 dB over the wide frequency range up to ten times the center frequency has been produced successfully. To widen the bandwidth of the edge‐mode piezoelectric filter, the double‐mode filter consisting of two acoustically coupled resonators is also proposed. Experimental results confirm the practical usefulness of this type of filter.
Digital filter realization based on simulation of the node equation of lc filters
Authors: Kitamura Tadashi , Hayahara Etsuro , Konishi Masayuki 
Published: July 2007

AbstractOne method of synthesizing a digital filter involves the simulation of an LC analog filter. This method retains the low element sensitivity that is characteristic of an LC filter and is generally attractive in that it requires only a small number of bits in the multiplier that is used to produce the filter coefficients. The web digital filter is a typical application of this design method and is known to possess low‐element sensitivity, but it involves a somewhat complex configuration and the transfer functions which can be realized are therefore limited. This paper discusses a method of designing digital filters by simulation of the node equation of LC filters. Using this method, the transfer function of an analog filter which can be implemented by means of LCR elements, including transformers, can always be realized. With this method, we first transform the LC filter into an equivalent circuit and determine the applicable node equation. Then bilinear transformation is used to transform the s‐variable into the z‐variable and, to prevent the occurrence of a delay‐free loop within the circuit, after rearranging the circuit equation it is realized as a digital filter. In addition, a study is made of methods reducing the number of multipliers without degrading the coefficient sensitivity. Finally, the effectiveness of this design method is verified by means of computer simulation.
Methods of controlling sound image distance by varying the cross‐correlation coefficient between two‐channel acoustic signals
Authors: Kurozumi Kohichi , Ohgushi Kengo , Nikaido Seiya 
Published: July 2007

AbstractA number of problems is involved in controlling sound image distance and such control has been realized only over a very limited range. This paper presents three methods of sound image distance control based on the knowledge that “if we vary the correlation coefficient continuously from 1 to ‐1, the sound image will move from a remote point to approach close to the observer's head.” Using one of these methods (the 90° phase shift method) in psychological tests, it has been found that the sound image broadening can be held almost constant while the sound image distance is varied. However, because the orientation of the sound image shifts within a horizontal plane with that system, it is necessary to employ an orientation‐correcting sound attenuator. As a means of automatically achieving this correction, we propose the α° phase‐shift system and it is shown that the approach of the sound is practically linear when α° is 70°. In addition, as a simpler circuit configuration, we propose the delay circuit system, which is shown to be effective for sound image distance control.
Measurement of lightning currents with different signs by magnetic links
Authors: Nagano Toshiharu 
Published: July 2007

AbstractIn regions experiencing intense thunderstorm activity, there are frequent failures of communication lines and equipment due to direct lightning strokes. For the effective application of lightning protection measures, it is extremely important that we have a good understanding of lightning current distributions. The magnetic link is known to be a convenient method of measuring lightning currents at a large number of grounding points. However, when currents of different sign are flowing, due to fluctuation in residual magnetism of the magnetic link, in regions experiencing concentrated lightning strokes it has not been possible to measure the lightning current by means of magnetic links.Using the nonlinearity of the magnetization curve, this paper examines the measurement of currents of different signs using magnetic links. We place magnetic links at two locations having magnetic fields of different strengths and when currents of different signs are present, from the measured values of the residual magnetism in the two magnetic links, we prepared a calibration curve from which we can determine the magnitudes of the currents in each direction. In addition, this method was used in the west central region of Africa to measure cable sheath currents, obtaining lightning crest value distributions which can be considered to be essentially the same as the distributions in Europe and America. This work has verified the effectiveness of this method of lightning current measurement.
Stable approximation methods by the interpolation of phase spectrum
Authors: Sakai Masayoshi , Member Nozomu Hamada, Regular 
Published: July 2007

AbstractThis paper proposes a method of stable approximation based on the phase characteristics, utilizing the properties of phase and the stability of discrete‐time all‐poletype transfer function. The feature of the method is that the characteristics to be approximated can be modelled by the ω‐coordinate (real‐frequency) of the interpolating points and a real coefficient parameter. When the method is used in the approximation in the time domain, the characteristics of the nonminimum phase system can also be approximated by the transfer function with zeros and by the processing using complex cepstrum. The extension of the method to the two‐dimensional signal processing is also discussed, although the discussion has to be limited to the separable case.
Chromatic temporal frequency response–appearance at retinal location under the superthreshold condition
Authors: Member Haruo Sakata, Regular 
Published: July 2007

AbstractThe chromatic temporal frequency response of human vision under the isoluminant condition has been measured psychophysically by using a color‐television monitor. The following results were obtained.(1) Under the superthreshold condition, the chromatic frequency response shows the lowpass filter type pattern.(2) The periphery between 5 to 10 degrees eccentricity is more sensitive than the fovea under 5 Hz.(3) In the fovea, the (y ‐ b) channel has the lower sensitivity similar to a tritan. In the peripheral retina, the (r ‐ g) channel has sensitivity lower than the (y ‐ b) channel similar to a deutan.
Boundary element analysis of polarization holding fibers
Authors: Matsuhara Masanori 
Published: July 2007

AbstractThe boundary element method has drawn wide attention as a novel numerical method of the boundary integration equation, and it has already been applied to the electromagnetic initial value problems. In this paper, we apply the boundary element method to the electromagnetic wave eigenvalue problems and establish a numerical method which is applicable to analyze the guided modes of waveguides with arbitrary structure. Then as an application example of the present method, we make numerical calculation of the elliptical core optical fiber, which is the typical polarization holding optical fiber, and clarify the cutoff frequencies of the first‐ and second‐order higher modes of the fiber. Also, the propagation constant and the geometrical anisotropy of the fundamental mode of the fiber are obtained. Again, the maximum anisotropy of the elliptical core fiber is shown to be obtained for the normalized frequency of 1.85 and ellipse factor of the core equal to 0.8. From these results we conclude that the boundary element method has high accuracy of calculation, is easy to apply, and has highly stable solution.
Dc stability of nullator‐norator‐modeled resistive networks realized with practical electronic devices
Authors: Member Yoshinobu Kato, Regular , Member Tadashi Matsumoto, Regular 
Published: July 2007

AbstractThis paper discusses the stability problem when a network is realized by using practical elements such as operational amplifiers and transistors for the nullors of the given nullator‐norator‐modeled resistive network. In other words, determination of the polarities of input and output terminals of the practical elements as well as the combination of nullators and norators is discussed. The stability of the network realized using practical elements is determined from the return difference matrix of the associated controlled source representation network. First, the first‐order phase‐delay ki/(1 + sTi) is assumed for the practical element and dc stability is defined as the asymptotic stability when the time constant Ti approaches zero. It is shown that the necessary condition for dc stability is that the determinant of the return difference matrix is positive when the phase‐delay of the practical element is ignored. Then, depending on the process of activation of the practical elements and their possible ranges of dc amplification factors ki, the absolute sequential, finite‐gain, equal‐gain and conditional dc stabilities are considered. The necessary and sufficient (or sufficient) condition is derived for each dc stability in terms of the expansion coefficients with respect to the dc amplification factors of the determinant of the return difference matrix. These results are useful in deriving the stable realization network using the practical elements from the nullator‐norator resistive network.
A synthesis method for the integrator of noninteger order in the continuously variable form
Authors: Matsuda Tsukasa , Kawakami Atsushi , Takahashi Shin‐Ichi 
Published: July 2007

AbstractThis paper proposes a method to synthesize an (differential) integrator of non‐integrator order applicable to a number of engineering problems in the continuously variable form. First, we approximate the desired characteristics by rational transfer functions which contradict two variables, the complex frequency s and the variable parameter λ corresponding to the order. These transfer functions have an approximation accuracy which is good enough for practical applications. The obtained approximated transfer function can be constructed by active networks consisting of a minimal number of dynamical elements and variable elements. It is also shown that the proposed method in this paper is applicable to a synthesis problem of a variable equalizer.
An analysis of repeated call model with a finite number of sources
Authors: Ohmura Hiroyuki , Takahashi Yoshitaka 
Published: July 2007

AbstractRepeated call model is one of the queueing models which appear in various communication systems. Repeated call model has been studied, but there has been little study on the finite source repeated call model. This paper deals with a single‐server service system with a finite number of sources and with repeated calls. Assuming that the arrival process is quasi‐random, the service time is drawn from an arbitrary distribution and the repetition interval is exponentially distributed. Traffic measures such as mean waiting time and mean number of waiting calls are derived by using the supplementary variable technique and the discrete transforms. A numerical example for the traffic characteristic is shown. The effect of repetition interval distribution is also studied by computer simulation. An application to disk memories in the Facsimile Intelligent and Communication System is given and the process waiting time is quantitatively analyzed. This evaluation is compared with the evaluation by the existing theory.
A test of the stability of the two‐dimensional recursive digital filter
Authors: Miura Hiroki , Koga Tosiro 
Published: July 2007

AbstractA test for the stability of a two‐dimensional recursive digital filter is proposed. Bilinear transformation reduces the stability test outside the unit circle in the complex plane to a test in the right half plane (i.e., to a test of a two‐variable Hurwitz polynomial for a continuous system). Conditions for a two‐variable polynomial to be a Hurwitz polynomial are given. The necessary and sufficient conditions for a two‐variable rational function to be a strict‐sense positive real function are given in a theorem. It is shown that a strict‐sense two‐variable positive real function can be found for each two‐variable Hurwitz polynomial. From the theorem it follows that the test of a two‐variable Hurwitz polynomial reduces to a test of a Hurwitz polynomial of a lower order with respect to one variable and to a sign test of a real two‐variable polynomial. The test of the two‐variable Hurwitz polynomial reduces to tests for signs of a set of real two‐variable polynomials. This is an extension of Sturm's test for the roots of a one‐variable algebraic equation.
Control algorithm and traffic analysis of PRT grade‐separated interchange
Authors: Satou Kousei , Kurihara Masahlto , Kaji Ikuo 
Published: July 2007

AbstractA control algorithm and a probability‐theoretical traffic analysis of a grade‐separated intersection model of the personal rapid transit (PRT) systems under the quasi‐synchronous scheme is presented. At the intersection, vehicles diverge from the less preferential subline and merge into the preferential mainline. To realize efficient cell‐assignment, this algorithm makes a slot‐slipping decision before the diverge point and performs the actual slot‐slipping after it on the off line. Even a diverge‐minded vehicle is forced to go straight (be adopted) when the number of maneuvering cells exceeds its limit and passes the intersection without the maneuver. The behavior of this algorithm under the random arrival assumption is formulated as a Markov chain, the analysis of which leads to the explicit expressions for the delay distribution, the average delay, and the abort rate.
Fundamental theory on natural observation of waveform
Authors: Iijima Taizo 
Published: July 2007

AbstractObservation of the waveform is a fundamental problem common to the problem treating various waveforms such as the voice. This paper attempts to provide a rational answer to this problem. Originally, the theory has been developed with the assumption of a simple condition called the natural observation condition. As a result, a simple and complete observation system has been developed which consists of only one original function and two observation types.Traditionally, the concept of a running spectrum has been known for the observation problem of waveforms. In such a concept, the temporal transition of the short‐term spectrum is studied. From this viewpoint, the present method is an extension of the concept and places a new theoretical foundation in a rational manner so that unclear points and self‐contradictions of the previous theory are corrected.
ARMA digital lattice filter with white gaussian input
Authors: Miyanaga Yoshikazu , Nagai Nobuo , Miki Nobuhiro 
Published: July 2007

AbstractThis paper presents a new synthesis method for ARMA digital lattice filters. These filters are obtained by a fast algorithm for estimation of ARMA parameters. Some fast algorithms for such estimation have already been proposed in which approximation models are derived using the input and output signals and can be applied to arbitrary input signals. Among these methods, the Mullis‐Roberts algorithm estimates the parameters by the autocorrelation coefficients and impulse response of observed signals. The method is similar to the parameter estimation using white Gaussian process for the input signals. Though the Mullin‐Roberts algorithm can estimate the parameters with less calculation cost than other algorithms, it is not suitable for designing different orders of the AR and MA parts. The fast algorithm proposed in this paper estimates the parameters with the same calculation cost as in the Mullis‐Roberts algorithm when the input signal is restricted to a white Gaussian process and obtains the ARMA parameters as the AR and MA orders are independently increased.The new ARMA lattice filter is synthesized by three prediction errors defined in the new algorithm and consists of a simpler structure than the usual filters of this type. By processing time series signals using the algorithm and the lattice filter, we show the feasibility of estimating the minimum realization for an ARMA model.
Indirect lightning surge at office terminal point on subscriber loop
Authors: Deguchi Fumihiko 
Published: July 2007

AbstractWith the objective of providing basic data for the design of lightning protection for communication devices connected to subscriber loops, this paper presents experimentally determined lightning surge characteristics of the office terminal point on subscriber loops or aerial and underground cable, covering such items as equivalent internal impedance, current and voltage distributions between lines and current additivity.The initial step in this effort was the assembly of a high‐precision multichannel lightning surge measuring equipment (80 channels) and, after verifying the equipment performance characteristics, measurements were made at the office terminal points on subscriber lines in actual use. As a result of the measurements it is shown that the lightning surge as seen from the office side of the subscriber loop can be modeled as a constant‐voltage source with the dc resistance of the underground cable subscriber loop wire as its internal impedance. In addition, it is verified that with a multiplicity of on‐premises terminations at the same point on the subscriber loop, regardless of the termination conditions, the lightning surge will be practically the same and will reach the office termination point with the same phase. Further, this study clarifies the nature of the lightning surge voltage and current distributions and the surge current additivity and also defines a detailed lightning surge model.
Theoretical and experimental study on rectenna array for microwave power transmission
Authors: Shimanuki Yasushi , Adachi Saburo 
Published: July 2007

AbstractIn using the rectenna array as a receiving antenna in microwave power transmission it is necessary to prevent spurious radiation of higher harmonics and from interfering with wireless communication paths and to achieve high efficiency in conversion of microwaves to dc energy. In this paper the conversion efficiency and spurious radiation of higher harmonics are examined by solving circuit equations which are transformed to difference equations with the use of Newton's method. The input impedance of the antenna is obtained by assuming an infinite planar array on a perfectly conducting plane. Consistent with the theoretical analysis, an experimental rectenna array is constructed and its performance is confirmed experimentally. The rectenna array is fabricated by mounting the diode and other components in a thin‐film LC circuit with soda‐glass substrate using MIC technology and by connecting it to a 69‐element half wave dipole array above an aluminum sheet.
Markovian model and analysis of a PRT 2‐berth station
Authors: Nakamura Takashi , Kurihara Masahito , Kaji Ikuo , Yoneyama Tadaaki 
Published: July 2007

AbstractVehicle behavior of a PRT (Personal Rapid Transit system) multiberth station has already been analyzed as a continuous time system under the assumption of Poisson vehicle arrival and exponential passenger loading and unloading time [2]. However, it is more realistic to model it as a discrete time system considering a widely used point‐follower control. Thereby a general passenger loading and unloading time can be easily treated. An off‐line station with two berths in PRT, in which vehicles move on a guideway under point‐follower control, is modeled and analyzed as a discrete‐time Markov chain in this paper. The state quantity is defined based on the physical state of two berths at the arrival instance of a cell. First it is shown that the inter‐entrance time can be calculated numerically for a general passenger loading and unloading time. Then, several measures of the station behavior such as mean inter‐entrance time, entrance frequency and entrance factor are analytically obtained for the case of fixed passenger loading and unloading time, the opposite of the exponential distribution. The differences between two berths and one berth are discussed by showing numerical examples.