bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bipolar monolithic very‐wideband amplifier
Authors: Kamoto Tsutomu , Ohara Mamoru , Kobayashi Yoshiji , Aiki Mamoru 
Published: July 2007

AbstractAnalog basic amplifier ICs (e.g., differential amplifiers, parallel feedback amplifiers, gain control amplifiers) and equalizing amplifier ICs for repeater circuits of high‐capacity optical transmission systems are designed using high‐speed bipolar technology (e.g., SST‐2). Particular consideration is given to reduction of base resistance, optimization of current density and pattern layout and improving breakdown voltage in applying this technology to analog circuits. Moreover, a peaking technique is applied to wideband amplifiers and a gain control amplifier is constructed which has wide linearity and can be directly connected to other differential circuits because of its constant dc level. For a differential amplifier with peaking, a gain of 15 dB and bandwidth of 1.4 GHz are realized. Expansion of bandwidth by peaking is also applied for the gain control amplifier and a gain of 28 dB, bandwidth of 630 MHz and a variable gain range of 30 dB are obtained. In addition, an equalizing amplifier with transimpedance of 70 ∼ 620 dB and bandwidth of 410 ∼ 620 MHz is constructed. Thus, it is evident that integrated repeater circuits for use in high‐capacity optical transmission systems can be realized.
A time‐series analysis method based on the directed transinformation
Authors: Kamitake Takashi , Harashima Hiroshi , Miyakawa Hiroshi 
Published: July 2007

AbstractIn a previous paper we presented procedures of analyzing causality between a time series based on information theory and information flow between time series based on a concept of directed transinformation, which is an information quantity with a direction. In principle, the directed transinformation is defined based on joint probability density between time series. As the length of the time series becomes larger, however, the volume of computation needed also increases exponentially. In this paper, we will discuss efficient computation algorithms. First, we assume Gaussian properties with the time series to present the “correlation function method” as a means of computing of the directed transinformation from correlation function. Second, we present a “linear production model method” in which the information quantity is computed by means of impulse response of a linear production model of the time series. Also, we proved that the linear production model can easily be composed by auto‐regression if the time series is steady. Finally, we discussed the validity of time‐series analysis based on the directed transinformation through analysis of an artificially produced simulated series. We have concluded that the proposed computation method can provide correct analysis even if the causality of the time series can not be analyzed correctly based on the correlation function.
Pattern synthesis of array fed reflector antennas
Authors: Mano Seiji , Katagi Takashi , Tsutsumi Takashi 
Published: July 2007

AbstractPhased array reflector antennas are used in practice for beam scanning in a limiting range of angles. Compared with the complete phased array systems, these antennas have a simple structure and can be constructed with a smaller cost. These arrayss fed reflector antennas can be replaced with generalized array antennas by considering the secondary radiation pattern of each feeding element of the array element pattern. This paper is a theoretical study of the maximization of the gain and suppression of the sidelobes for this generalizeed array. These problems are important for pattern synthesis. From the study, it was found that the computation time of the synthesized secondary pattern can be reduced for the array fed reflector antenna due to exploitation of the secondary element patterns. Also, the array excitation distribution optimum for the desired pattern can easily be determined from the theory of the generalized array. These findings have been confirmed experimentally by means of an X‐band linear array fed reflector antenna.
Analysis and control of reattempt phenomenon
Authors: Shinohara Masaaki 
Published: July 2007

AbstractThe hysteresis phenomenon caused by the reattempt process can be observed in overloaded communication networks and the intensity of this phenomenon is affected by the reattempt parameters, such as reattempt probability, reattempt interval, etc. This paper proposes a macroscopic analysis method for the reattempt system model and clarifies the mechanism of the hysteresis phenomenon by introducing the concept of stability index which characterizes the transient behavior of the system. Moreover, the optimum control strategies of the number of repetitions for two different service models are discussed.
Stress birefringence in YIG and Bi:YIG thin films
Authors: Mizumoto Tetsuya , Tsuchida Manabu , Banno Junichi , Naito Yoshiyuki 
Published: July 2007

AbstractTo obtain a mode converting optical isolator it is necessary to achieve phase matching of the TE and TM modes propagating through the magnetic film, such as a rare‐earth garnet, etc. One of the methods of phase matching employs the birefringence induced by a lattice parameter mismatch between film and substrate. This paper presents measurement of the birefringence in YIC and Bi:YIG films grown on a GGG substrate using liquid phase epitaxy. Moreover, birefringence evaluated from the optoelastic effect and the stress calculated using a bimetal model agree well with the measured values. From these results, the birefringence induced in YIG and Bi:YIG films can be obtained theoretically. It is established that a phase‐matched magnetic waveguide can be obtained using Bi:YIG thin film. Further, by using such films nonreciprocal mode convertors and isolators can be realized.
A method to obtain the specified N‐port networks from voltage and current graphs and its application to the topologically minimal realizations for generalized immittance converters
Authors: Matsumoto Tadashi , Hibino Kazuhisa 
Published: July 2007

AbstractA report was previously made on problems, for given port characteristics of a functional resistive two‐port, to determine the lower bound for the number of elements needed in the topological realization of the characteristics with nullors and resistors, or to determine the voltage and current graphs GV and Gi. The algorithm to determine the two‐port in the nullor model from Gv and Gi has also been published for simple cases [7, 8]. This paper describes, for given Gv and Gi for an Nth order real square matrix, a generalized algorithm to determine the nullor model N‐port with specified port characteristics. The algorithm is applied to the topologically minimal realization of the generalized immittance converter (GIC) to determine all possible minimal GIC realizations. The algorithm forms a basis for the proposed topological network synthesis, which is a kind of structured system synthesis. Various applications of the idea as well as the determination of Gv and Gi from an Nth order real square matrix are also discussed.
SAW‐resonator stabilized voltage‐controlled‐oscillator for PLL‐FM modulator
Authors: Urabe Shuuji , Habuka Tatsuji , Matsuura Takashi 
Published: July 2007

AbstractA voltage controlled oscillator using a SAW resonator does not need multiplication and tuning in the 100 MHz ‐ UHF band so that miniaturization and circuit simplification can be achieved. It also has the feature that less power is dissipated than with a SAW delay line. In this paper the SAW resonator voltage‐controlled oscillator (SAWR‐VCO) is used as a modulator suitable for a phase locked loop (PLL) and its modulation sensitivity and distortion are analyzed. Tests confirm the analysis of SAWR‐VCO performance. Finally a PLL modulator structure and the modulator circuit for use in an automotive mobile telephone unit is described.
1‐GHz 2‐modulus prescaler MSI with a direct feedback loop
Authors: Yamashita Kiichi , Kaji Tadao , Kanouta Keiji , Sekine Yasushi 
Published: July 2007

AbstractThis paper describes the design and observed performance of a 2‐modulus prescaler MSI developed for a pulse‐swallowing variable frequency divider at 1 GHz. The output of the final stage is fed directly back to the first stage to achieve high‐speed operation. The operating speed is 1 GHz for a source voltage of 5 ± 0.5 V and ambient temperature from −40 to +85 C; the maximum speed is 1.3 GHz. The power consumption is 400 ‐ 450 mW. The frequency division ratio is 1/64 and 1/65. Series gate ECLs are used for the basic circuit and the logic amplitude is 0.5 V. The chip size is 1.78 × 2.08 mm2and includes 285 transistors and 170 resistors. Transistors with emitter size of 3 × 5 μm2and qualityn‐type resistors are used in the high‐speed circuit.
Fast convolution methods for hexagonally sampled two‐dimensional signals
Authors: Morikawa Yoshitaka , Kaneda Masahiro , Hamada Hiroshi 
Published: July 2007

AbstractFor fast convolution operations on one‐dimensional signal sequences there is the fast cyclic convolution (FCC) method based on sectioning. Also, for a two‐dimensional signal sequence in the convolution operation of a rectangularly sampled signal sequence and a convolving sequence arranged in rectangular blocks, an FCC method based on rectangular sectioning has been reported. On the other hand, two‐dimensional signals band‐limited over a circular region are sampled hexagonally. This arrangement of the convolving sequence in hexagonal blocks to provide it with 12‐fold symmetry is most effective. This paper describes an FCC method based on sectioning for such types of hexagonally sampled signal sequence and convolving sequence arranged in hexagonal blocks, Presupposing the use of a fast Fourier transformation (FFT) of base number 2 in the discrete Fourier transformation in FCC, two types of FCC (hexagonal sectioning and parallelogrammatic sectioning) are proposed and overlap‐and‐save algorithms for these two are given. Also, it is shown that there exists an optimal sectioning block size for which the number of numerical operations becomes minimum in both methods. Next, for both types, the number of numerical operations are calculated and compared. Due to the limited memory capacity useable in FFT calculation, if convolution is not possible with optimal sectioning, the hexagonal sectioning method is advantageous. However, when the memory size is sufficiently large, it is difficult to say which of the two is better.
Line codes and repeater fault location schemes for optical transmission systems
Authors: Kitami Tokuhiro , Yoneda Etsugo 
Published: July 2007

AbstractIn this report, the line code structures of optical transmission systems are compared from the viewpoint of providing bit sequence independence (BSI). Repeater fault location schemes are also studied. Initially, we shall describe what considerations should be made to avoid consecutive identical codes as well as pseudo‐synchronism in accordance with the inherent meaning of BSI, and we shall show a specialized code pattern to be considered for protecting pseudo‐synchronism and a frame format to avoid pseudo‐synchronism. Furthermore, we shall show the repeater fault location schemes for the phase‐difference‐detection type of CMI code transmission system and the m BIP code transmission system with odd parity, and we shall indicate how simple they are to realize. Then the transmission line code schemes of the 100 Mb/s optical cable transmission system are compared, and it is concluded that the preferable frame format is that in which frame synchronization pulses are inserted at positions different from the parity bits based on the 7 BIP code. In addition, experimental studies of the characteristics of the timing system in the repeater of the DF‐100M system [1] will indicate the appropriateness of the design jitters and the selection of the frame format of the repeater.
A consideration on broadbanding of n‐way hybrid power dividers
Authors: Watanabe Hiroshi , Nagai Nobuo , Ono Koujiro , Hatori Kozo 
Published: July 2007

AbstractA method is presented for broadbanding an n‐way power divider in which an absorbing resistor is used in one section. In the conventional Wilkinson power divider, it is known that the waves, equally reflected at the terminations, are absorbed by a resistor at the center frequency if a quarter‐wave line is connected to one of the output ports. To construct a 2n‐way power divider from a combination of these two‐way power dividers, 2n sections of lines are needed. In this paper, we constructed a network, which absorbs reflected waves, by connecting a 1/4‐wavelength section to an n‐way one‐section power divider if the characteristic impedance of the line and the absorbing resistor are optimized by numerical calculation. The circuit shown in the text has a broadband VSWR characteristic if attenuation of the transfer at the center frequency is permitted. The transmission characteristics then become flat, and the isolation characteristics are also improved.
An untrimmed monolithic 14‐bit D/A converter
Authors: Maio Kenji , Hotta Masao , Kaneko Kenji , Yokozawa Norio , Nagata Minoru , Hanada Seiji 
Published: July 2007

AbstractRecently, a need has arisen for an economical untrimmed 14 ‐ 16‐bit D/A converter in the field of digital audio and precision metrological systems. However, the precision of the monolithic D/A converter is about 10 bits to date, which can be improved to 12 ‐ 13 bits by applying a special trim technique. In order to obtain the required high‐precision converter, a self‐correcting equation is established to treat the error involved. The result—a monolithic IC—has been studied experimentally.For the most part, this paper discusses the circuit structure and the test results of the monolithic 14‐bit, DAC developed on the basis of this self‐correcting equation. The monolithic DAC was prepared by combining the type I2L digital analog process and the two‐layer microwiring technique and exhibited a linearity of ±1/2 LSB (±0.003%) and a setting time of 1.2 μsec.
A method for measuring amplitude and phase of each radiating element of a phased array antenna
Authors: Mano Seiji , Katagi Takashi 
Published: July 2007

AbstractIn the phased array system, excitation amplitudes and phases based on the design are specified for each antenna element in order to synthesize desired beam scannings and radiation patterns. However, due to fluctuations of antenna and feed network characteristics, the amplitude and phase of each antenna element deviate from the desired values. To correct these deviations, the amplitude and phase of each antenna element must be accurately measured under specific operating conditions. In this paper, we employ variable phase shifters connected to the antenna elements and measure only the amplitude variation of the composite electric field of the entire array when the phase of each element is modified. The rotating element electric field vector method in which the measured amplitude variation is numerically processed for obtaining the amplitude and phase of the particular element is theoretically discussed and experimentally tested for its usefulness. The present method can be easily attained by simply adding software to the computer‐controlled phased array system.
On the interleaving for elimination of destuff errors due to 4B‐3T code transmission error extension
Authors: Ohue Kenji , Yoshikai Noriaki 
Published: July 2007

AbstractThe error extension of 4B‐3T code causes some problems to destuff error of the stuff indicating pulses. This paper investigates the characteristics of error extension associated with 4B‐3T code transmission, and proposes a method to eliminate the adverse effects of the error. Involved are the interlease and rearrangement of the stuff indicators, pulses in the binary code before conversion to ternary code. The optimum conversion method is described. An experimental 4B‐3T code transmission system is constructed to evaluate the characteristics of error extension and destuff error. Further, this system demonstrates that the proposed 16 bits interleave method results in a destuff error rate comparable to that of the AMI transmission method and only a few hundredth of that of the conventional 4B‐3T code transmission without interleave.
Probabilistic analysis of a heuristic graph coloring algorithm
Authors: Kawaguchi Tsuyoshi , Nakano Hideo , Nakanishi Yoshiro 
Published: July 2007

AbstractIn this paper a heuristic graph coloring algorithm as applied to random graphs is analyzed theoretically. The result obtained by expanding on the results of [4] is presented first: let x1(n, cnδ−1) be the random variable representing a solution obtained by applying the algorithm to a random n‐vertex graph having edges with probability p(n)=cnδ− (where c is a constant and 1/2≪δ≦1). Also let x1(n, cnδ−1) be the random variable representing the chromatic number of the graph. Then x1(n, cnδ−1)/x*(n, cnδ−1)≦(1+ϵ)2δ/(2δ−1)(pr.) holds. Here ϵ represents a value sufficiently smaller than 1. By contrast, it is important from the practical point of view to find an algorithm that is effective for an arbitrary random n‐vertex graph. In this paper the above‐mentioned algorithm is evaluated using models with p(n)≪ It is found that this algorithm is effective for all n less than N, where InInN is about the same as np(n).
A solution to a multi‐object decision problem for distributed‐parameter control system
Authors: Shimizu Kiyotaka , Katayama Ryu 
Published: July 2007

AbstractThis paper discusses the static multi‐object control problem for a distributed system in which more than one geographically distributed decision‐maker (control station) performs control based on their own object functions. The object function of the control station is given in an integral form, with the range of integration being limited to an interval which is of interest to the control station. Then the multi‐object control problem is formulated as an optimization problem for a vector functional, leading to the optimality condition. The paper further discusses the multi‐object decision problem to determine the unique optimal control input from the set of non‐inferior solutions of the multi‐object control problem. The problem is called the central decision problem, where there exists an upper‐level decision maker and his preferable solution is determined based on the global viewpoint and the central object function. The problem is called a set decision problem when such an upper‐level decision maker does not exist, and the solution preferable to the set members is selected for the benefit of the whole set. A method of solution with two steps is proposed using the restricted simplex method and internal point penalty method. The gradient method is used for numerical computation to optimize the system of partial differential equations.
On a hybrid network system of circuit switching and packet switching
Authors: Nakamura Yatsuka , Noda Akishige 
Published: July 2007

AbstractThis paper describes the architecture of a hybrid switching network employing both circuit switching and packet switching. The network usually operates in a packet switching mode, but, depending on the traffic conditions, it can use special control packets to temporarily change certain lines to a circuit switching mode. The change between the two switching modes is performed dynamically depending on the traffic load of the network. Also described in this paper is the concept of metapacket which can be employed in some relatively small‐scale networks to average the load of packets and to reduce data transmission time.
An optimization method of super‐synthesis observation by “number of weighted holes”
Authors: Morita Koh‐Ichiro , Ishiguro Masato 
Published: July 2007

AbstractIn radio astronomy by a super‐synthesis array the element antennas are rearranged and the rotation of earth is also used. By such arrangement, the spatial frequency components of radio source distributions are measured and are subsequently Fourier transformed for radio photographs. Spatial frequency components detected are determined by the element arrangement. Therefore, the element arrangement is important for effective tive use of the array. This paper discusses the number of weighted holes, which is proposed as a criterion for evaluation of the characteristics of element arrangement. As a method for analysis, we use random number trial experiments by computer and show from the results that the number of weighted holes becomes a good indication of the peak sidelobe level under an appropriate condition. Further, we propose a method of optimizing the element arrangement using this evaluation criterion. Its usefulness is confirmed by a simulation of super‐synthesis.
Speech recognition by polarized linear predictive error coding—POLPEC method
Authors: Akagi Masato , Iijima Taizo 
Published: July 2007

AbstractThis paper describes the polarized linear predictive error coding method (POLPEC), which is a new scheme for speech recognition. Although the residual waveform power method, which is a method of speech recognition using an inverse vocal tract filter, has the advantage that the processing for recognition is simple and is suited to parallel processing, it has the drawback that it is sensitive to deviation of the input waveform to the inverse filter (i.e., the speech waveform). From such a viewpoint, this paper introduces the polarized linear predictive error coding method, which is a recognition scheme, in which it is assumed that deviation in the speech waveform is due to change in the pole of the transfer function of the filter for speech generation (called vocal tract filter) and, by improving the residual waveform power method, the sensitivity to the change of poles is decreased. The POLPEC method has the effect of decreasing the residual power by subtracting from the residual waveform sequence the component which is due to the deviation of poles. It is verified by experiment using synthetic speech that this reduces the sensitivity to the predetermined deviation of poles.
Four‐terminal circularly polarized self‐complementary antennas
Authors: Kasahara Takeshi , Mushiake Yasuto 
Published: July 2007

AbstractCircularly‐polarized high gain antennas are needed for communication via broadcast or maritime satellites. With a view to developing a wideband circularly‐polarized antenna, we discuss experimental results for a structure consisting of a planar four‐terminal self‐complementary antenna on a core. The four conductors have a toothed shape which improves linear polarizability. The entire antenna structure is such that the sizes of the gaps and conductors are either equal or slightly modified. First, coupling between two opposing plates is qualitatively studied by measurement of the impedance and the radiated electric field. The self‐complementary nature of the antenna is confirmed. Next, the directivity, beam width and axial ratio of the circular polarization are studied. When the sizes of the conductors and gaps on the core are identical, the coupling between two orthogonal terminal pairs is small and the self‐complementary nature is practically preserved. This antenna has highly constant impedance and excellent directivity. The axial ratio of the antenna system, including the hybrid feed structure, is less than 0.8 dB over a large bandwidth.