bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study on satellite circuit assignment and dimensioning methods for a domestic telephone transit network
Authors: Member Kou Miyake, Regular 
Published: July 2007

AbstractIn applying satellite circuits to a large domestic telephone network, it is necessary to study channel assignment and dimensioning methods that take advantage of broadcast communication features. This paper shows that for a large‐scale telephone transit network which has hierarchical structure, in order to absorb traffic fluctuation, it is attractive to apply satellite circuits to high‐usage trunks in combination with terrestrial final trunks, by taking the Japanese telephone toll network as an example. Assuming this network construction, this paper considers three different satellite channel assignment schemes—Pre‐Assignment, Timed Pre‐Assignment, and Demand Assignment–and introduces a circuit capacity dimensionsing method to minimize the total network cost for each assignment. Finally, a comparison of channel capacity and network cost is made among these assignments under some traffic variation patterns. It was found that Timed Pre‐Assignment is the most effective and economical scheme. Demand Assignment is a future technology and its application field is clarified in comparison with other schemes, with the cost increase for realizing Demand Assignment as a parameter.
A study on system fluctuations based on the nondeterministic operator theory
Authors: Horiuchi Kazuo 
Published: July 2007

AbstractThis paper considers the nondeterministic operator G defined on the direct product space of a completely matrizable linear space × and a metric space Y; G is introduced as a projective set G (x, y) ⊂ × for arbitrary × ϵ × and y ϵ Y. Relating to the completely continuous operator f(x) with Y as the range, a fixed‐point theorem is given for the generalized operator equation × ϵ G (x, f(x)). This mathematical theory is applied to the analysis of deviation of the output response when a nondeterministic fluctuation is imposed on the internal structure, internal parameter or input signal of a system. As a result, clear definitions are given for the tolerability and quasitolerability of the system fluctuation, the stability and quasistability of the system, and the tolerability and quasitolerability of the system model and simulation by it. An aspect of the system's sensitivity analysis is also discussed. Of particular importance in this paper is the new proposal of the new concepts of quasitolerability and quasistability, which suggests that these concepts should be utilized more widely the notions of the system and its model by developing the computing abilities.
Arma spectral approximation methods with weighting functions
Authors: Watanabe Hiroshi , Miyanaga Yoshikazu , Miki Nobuhiro , Nagai Nobuo 
Published: July 2007

AbstractThis paper presents an approximation method of the ARMA model using frequency weighting functions that are represented by the ARMA models. The parameters of the approximate ARMA model are calculated with the order update recursion. By selecting the weighting function appropriately, the spectral approximation method weighted the polezero frequency of the original model can be obtained. The relation between the proposed approximation method and the spectral distance measures is also considered. The behavior of the proposed method is illustrated by simulation results.
A maze running router and its wirability for single‐layer printed wiring boards
Authors: Member Takashi Shimamoto, Regular , Sakamoto Akio , Members Akio Ushida, Regular 
Published: July 2007

AbstractAs the integration in electronic equipment progresses, CAD technology becomes more and more necessary. Single‐layer wiring is one of the CAD technologies and some procedures have already been proposed. Primarily, the maze running‐type algorithm is used in them and the shortest path obtained by the algorithm is used for the routing path. In this paper to check the appropriateness of the shortest path selection policy, we present a new maze running‐type algorithm which gives near‐shortest path routes, and compare its wirability with other existing maze methods. One of the features of our algorithm is that if some obstacles exist between two vertices to be connected, a path along the obstacles is found. The path may not be the shortest one, but it becomes easy to implement the succeeding routing since the path along the obstacles preserves the force area as wide as possible. Furthermore, the computation time is shorter than existing maze methods because of a simple stack operation. As a result, the proposed maze running router is expected to give a high wirability with small computation time.
Mic linearizer for satellite communications
Authors: Member Gunkichi Sato, Regular 
Published: July 2007

AbstractThis paper describes the trial production results for two linearizers, one being a compact, lightweight MIC linearizer developed to improve the input‐output nonlinear characteristics of an earth station HPA and the other being a new soft‐limiter linearizer (SL‐LRZ) followed by an amplitude limiter. The symmetric construction of the MIC linearizer is easily implemented with MIC techniques, operates over a wide frequency band and its nonlinearities can be controlled electrically. Also, the transfer characteristics of a TWTA with SL‐LRZ are such that its amplitude response is linear up to saturation, it maintains constant output level beyond saturation and phase shift is not likely to occur. The TWTA with SL‐LRZ can reduce intermodulation products due to nonlinearities of the TWTA in amplification of multiple carriers and can improve transmission performance when a band‐limited PSK signal is amplified at close to saturation. The test‐fabricated SL‐LRZ is sufficiently small and lightweight for on‐board application.
Channel multiplexers for broadcasting satellite transponders in the 12 Ghz band
Authors: Member Toshihiro Nomoto, Regular 
Published: July 2007

AbstractThis paper describes the design and development result of high‐power (over 100 W) channel multiplexers for broadcasting satellite transponders in the 12‐GHz band. The input multiplexer which requires steep attenuation characteristics consists of two light‐pole canonical dual‐mode filters with an orthomode T‐shaped junction suitable for waveguide manifolds. Attenuation at adjacent channel edges AP is 40 dB, insertion loss at channel center A0 is 1.4 dB, and amplitude variation AV = 0.6 dBP‐P. The output multiplexer which requires low insertion loss consists of four‐pole longitudinal dual‐mode filters. To decrease insertion loss, several considerations are applied such as use of the TE113 mode, optimization of coupling apertures and materials of tuning screws. The characteristics of a fabricated four‐channel multiplexer (A = 15 dB, A0 = 0.6 dB, AV = 0.3 dBP‐P) are shown to be unchanged in the thermal test. These multiplexers can satisfy the necessary characteristics required to channel multiplexers for high‐power broadcasting satellite transponders in the 12‐GHz band.
Arrangement of sources in the charge simulation method–the case of e‐wave scattering by one perfectly conducting cylinder of convex cross section shape
Authors: Komiyama Akira 
Published: July 2007

AbstractThe charge simulation method has the following characteristics compared with other approximate methods for the scatteirng problems: (1) Only the zeroth and first‐order Hankel functions are used; (2) no processing of the singularities on the boundary is needed; (3) no numerical integration is necessary. As a result, it is an extremely simple method. However, the arrangements of the sources and contour points are arbitrary and such arrangements affect the accuracy of the approximate solutions. Previously, the source arrangements by the boundary contractions have been used in the charge simulation method. This choice provides good results if the shape of the scatterer is close to a circle or is a circle itself. The accuracy becomes poorer as the shape deviates more from the circle. Also, it is not possible to determine beforehand the arrangement that provides the best result. Hence, the boundary contraction is an important arrangement method. In this paper, arrangement of the sources and contour points is determined by means of the conformal mapping that transforms the boundary to a circle. Numerical calculations have been performed for typical convex shapes. It is found that the charge simulation method based on the present arrangement has the following properties. It exhibits much better accuracy than the arrangement by boundary contraction. The arrangement minimizing the error is found from the conformal mapping. Scatterers with edges on the boundary cannot be analyzed.
Cascade‐connected echo canceller
Authors: Takahashi Kenzo , Members Takashi Sakamoto Regular 
Published: July 2007

AbstractEcho cancellers are used in telephone channels with long propagation delay to prevent speech quality deterioration due to echoes. The circuit structures of conventional methods tend to be redundant to meet the various cases of near‐end delay predicted in a real channel and to correct impedance mismatching at 2/4‐wire transform points. This paper proposes an echo canceller composed of m cascaded echo canceller units. It can accommodate an echo path delay m times the maximum near‐end delay accommodated by a unit circuit. By adapting the size of the circuit unit to VLSI fabrication and choosing the proper value of m, an echo canceller composed of single‐kind units and with little redundancy can be constructed. As a result, miniaturization and economization are achieved. This paper discusses the construction method of a unit circuit, the procedure of cascade connection, the operation principle and its performance. The experimental results are also shown.
Nonstationary analysis by bpes (backward prediction error space)
Authors: Kiryu Tohru , Iijima Taizo 
Published: July 2007

AbstractThis paper describes a method of non‐stationary analysis based on the geometrical orthogonal projection with least‐squares estimation for a linear model. In the past, local stationary analysis and adaptive methods which successively estimate the parameters have been used for this purpose. However, in application to the nonstationarity case as in biomedical signals these methods have the disadvantage that it is difficult to see the physical significance of the parameters. In consideration of this, the present paper defines the backward prediction error space (BPES) consisting of the backward prediction error vector in each dimension and proposes to handle the nonstationarity by expanding the property into the orthogonal states in each dimension. The backward prediction error vectors constitute an orthogonal system in the least‐squares estimation and the reflection coefficient is the parameter directly related to this system. The orthogonality can be interpreted in direct relation to the independence of physical functions. As a measure of the nonstationarity, the angle between the vectors is adopted in the BPES. When the parameters which were optimum in the stationary interval are applied to an arbitrary interval, the angle is an exact expression of the discrepancy due to the nonstationarity. By an example of analysis of biomedical signals it is verified that the angle is useful in evaluation of the nonstationarity, especially of that arising from the change of orders. Thus, it is anticipated that the deterministic nonstationary analysis by BPES will provide new information about biological systems.
Differential companding PCM (DC‐PCM) by removed bit accumulation
Authors: Takahashi Susumu , Tanaka Masanori , Kameda Hiromi , Kanzaki Hiroyuki 
Published: July 2007

AbstractA new PCM transmission system is proposed. At present, near instantaneous companding is being considered as one of the PCM sound transmission methods for satellite broadcasts. Its quality performance and efficiency, however, are not satisfactory in every respect. The system proposed in the present article combines differential PCM with a near instantaneous companding capability. By combining the advantages of both methods, a very remarkable improvement is achieved in the lower frequency signal band and high transmission efficiency is realized at the same time. It is not enough merely to combine differential PCM with near instantaneous companding because bit removal during compression results in difficulties in transmission or signal restoration. This problem has been solved by the so called removed bit accumulation method. In this way, the two techniques can be united, resulting in a dramatical reduction of quantizing noise. This paper explains the principle of this system, describes its features and performance, based on the results of computer simulation and of measurements made on an experimental equipment, and discusses its operation. Comprehensive subjective tests have also been performed and the results demonstrate that high quality sound transmission is achieved even by an 8‐bit transmission channel. Also, the realization of the equipment is fairly simple.
Length dependence of cutoff wavelength for single‐mode fiber
Authors: Kitayama Yoshinobu , Tanaka Shigeru 
Published: July 2007

AbstractThe effective cutoff wavelength of single‐mode fiber cable cannot be completely determined because the bending loss, which prevents propagation of the second‐order mode, depends upon the bending distribution of the fiber as well as on the length and index profile of the fiber. By measuring the bending loss of the LPn mode of step‐index single‐mode fiber, it is found that the effective cutoff wavelength of reel‐wound fiber shifts to lower wavelengths along the distance. The length dependence is proved by experiment and agrees well with the theory. The length dependence of the cutoff wavelength of optical cable is estimated by experiment and it is established that the effective cutoff wavelength can be prescribed by the microbending profile and, compared with the value given by the conventional bend method of a 2‐m sample, the decrease in effective cutoff wavelength for 1‐m cable is estimated as 0.1 um. If this length dependence is used, it can be applied in long‐distance systems provided a fiber having longer cutoff wavelength and favorable.bending loss characteristics or low dispersion is used.
Tree encoding of images using a nonlinear smoothing filter
Authors: Handa Shiro , Tanaka Hatsukazu 
Published: July 2007

AbstractThe DPCM system is often used for encoding images, but particularly in low‐rate encoding methods, two types of noise of different nature (e.g., overload noise and granular noise) are introduced. In this paper a tree encoding scheme is applied to image signals and a design technique for an encoding filter is shown which is a combination of a least‐mean‐square filter derived from linear prediction theory and a nonlinear smoothing filter. The purpose of this nonlinear filter is to decrease the above‐mentioned noise. Its construction is like that of an adaptive quantizer in which one of the preassigned output levels is selected, keeping in view the previously encoded symbols. The linear smoothing filter used in tree encoding of speech is a special case of this sytem. Moreover, the conditional mean output level for the present encoding symbol matches the output level of the Lloyd‐Max quantizer for the Laplacian density function. The results obtained by applying this scheme to a head and shoulder image having clear boundaries are compared with the results without using a nonlinear smoothing filter and improvement of about 2 dB in SNR is obtained when the encoding rate is 1 bit/pixel.
A proposition of the load‐dispersion routing method in telecommunication networks and its evaluation
Authors: Kawarazaki Masatoshi 
Published: July 2007

AbstractThis paper proposes a load‐dispersion routing method as an improvement over the conventional alternate routing method. In this routing method, a part of the load is offered directly to the second route when the first route is overloaded and the overflow traffic of the rest of the load from the first route is offered to the second route. This is based on the property that the less bursty the offered traffic is, the less loss probability it experiences. It is shown that under this routing method the network throughput can be increased without any notable deterioration of first‐route traffic over the alternate route.The method of removing one out of K calls is considered and it is shown that the burstiness (peakedness) of dispersed traffic and overflow traffic is reduced. Furthermore, two traffic models used for the evaluation of this method are analyzed. That is, an accurate analysis is made of the overflow characteristics of the M‐Efe/M/S/S model (input to the loss system is Poisson with one out of K cells removed periodically) and the Eg + H2/M/S/S model (input to the loss system is a mixture of generalized‐Erlang and hyper‐exponential inputs).
Study of spurious solutions of finite‐element method in the three‐component magnetic field formulation for dielectric waveguide problems
Authors: Koshiba Masanori , Hayata Kazuya , Suzuki Michio 
Published: July 2007

AbstractThe cause of spurious solutions, which are included in the earlier finite‐element formulation of the three magnetic field components, is discussed. To eliminate these spurious solutions, a new functional is proposed. In the finite‐element analysis using this new functional, earlier spurious solutions do not appear but new ones appear. Reasons are given for these phenomena. The new spurious solutions are equivalent to the TE modes of “hollow” waveguides and their appearance is limited to the “fast‐wave” region. Therefore, if one is interested only in the solutions in the “slow‐wave” region which correspond to the surface‐wave modes of dielectric waveguides, the appearance of new spurious solutions is not a serious problem. The finite‐element program based on the new functional is coincident with that based on a Galerkin procedure. This fact proves the validity of both finite‐element programs.
A state equation approximation for a multi‐input/multi‐output system
Authors: Tomiyama Shigenori , Kojima Norio , Matsuura Takenobu , Shinozaki Toshio 
Published: July 2007

AbstractThis paper discusses the problems associated with the state equation approximation of linear shift invariant systems when a multi‐input/multi‐output system is given. First we present the approximation method to obtain the state equation for the system and then we present a method for stabilizing a rational function which is not physically stable. By iterative application of the approximation method we can always obtain a controllable, observable and physically stable system.The approximation method presented in this paper first considers a system which has multiple inputs and one output sequence and then makes minimum‐order estimates of the sequences to the desired precision and arranges the output sequences in increasing order. We then approximate the state equations which satisfy the output sequence of lowest order and the multiple input sequences. This is a method of approximating the state equation for the second and subsequent output sequences by effectively employing the state variable already obtained. If at the approximation stage a physically unstable rational function is obtained, one can use the technique of first shifting the pole to form a stable function and then determine the coefficients of the numerator polynomial so as to minimize the squared sum of the errors in the output sequence.
Outer electromagnetic field of helical coaxial line with regard to earth effect
Authors: Suzuki Mitsunori , Chiba Jiro , Hosono Toshio 
Published: July 2007

AbstractThis paper describes theoretically and experimentally the outer electromagnetic field of the two‐layered helical coaxial line which is constructed on the ground. First, the relationships between a transmission constant, material, and the structural parameter of the two‐layered helical coaxial line were formulated. Then the outer electromagnetic field was presented with a coupling impedance defined in each E and H mode. Although the effect of earth conductivity can be expressed with an equivalent current image of the earth, this paper proposes a new approximated formula, which can be applied to a surface wave mode having a large effective wavelength ratio. The H‐mode has a smaller effect due to the earth conductivity compared with the E‐mode. Thus it is obvious that large magnetic permeability of a magnetic core which excites the H‐mode is effective in the enhancement and stabilization of an electromagnetic field. The convergence of an electromagnetic field along a line which is the feature of the two‐layered helical coaxial line and the effectiveness of the approximated formula in this paper, were confirmed by the experiments taken for an externally constructed long line.
Characteristics of quasi‐monomode fibers
Authors: Yamauchi Ryozo , Sugawara Yasuyuki , Murayama Toshiyuki 
Published: July 2007

AbstractIn monomode fiber the attenuation of higher order modes is much larger than that of the dominant mode near the cutoff wavelength. Therefore, in practice, the wavelength region in which only the dominant mode propagates is extended toward the shorter wavelength. A fiber used in the region in which two LP modes can theoretically propagate is called quasi‐monomode fiber. This paper investigates the characteristics of the quasi‐monomode fiber for application to communication channels. The behavior of the two modes near the cutoff wavelength is studied. The transmitted pulse waveforms, the effective cutoff wavelength and microbend loss are investigated. Based on the results, conditions for effectively preventing multimode dispersion are found even when coupling exists between these two modes. These conditions include the difference in loss factors, the coupling coefficient between the two modes and the relation between the fiber junction distance and the transmission distance. A measurement method is proposed for the coupling coefficient. It is shown that coupling of the two modes due to microbends, which are important for cable fabrication, creates increased loss not strongly dependent on the wavelength. Dependence of the effective cutoff wavelength on fiber length is clarified. It is shown that the effective cutoff wavelength of an entire length of cable can be estimated from a short sample.
A 3‐port ferrite resonator circuit using slot line
Authors: Ohwi Koichi , Okada Fumiaki 
Published: July 2007

AbstractThis paper proposes a magnetically tuned 3‐port circuit having simultaneously a resonant characteristic and a nonrecriprocal property. In this circuit, a ferrite resonator is placed on the metal conductor side of a slot line on a dielectric substrate and an additional port is created that couples with the resonator. The S matrix of the circuit is derived. The relation between the electromagnetic field and the external Q of the resonator is found and the electromagnetic field distribution of the slot line is calculated. From the calculated results, it is found that there exists an optimum location for the ferrite loading and that the present circuit can be used in a broadband operation. The frequency characteristic and the nonreciprocity are experimentally confirmed. The present circuit has a simple configuration and can be used for a magnetically tuned oscillator that does not require an isolator to eliminate the effect due to load variation.