bluuebunny/crossref_metadata_2025_split huggingface dataset:
Considerations of SNR improvement characteristics of the optimum linear filter of systems with signal‐dependent noises
Authors: Kuwahara Ichiro , Takahara Mikio , Amemiya Masaki 
Published: July 2007

AbstractThis paper proposes a new expression model of signal‐dependent noises such as shot noise, multiplicative noise, etc., by introducing signal dependent index n. the optimum linear filter on the signal‐to‐noise‐ratio (SNR) criterion in transmission systems containing additive noise, some signal dependent noises, and intersymbol‐interference, is derived. the optimum filter can be regarded as an extended matched filter from the used criterion. By assuming Gaussian input signal waveforms, SNR improvements by the optimum filter are obtained through numerical calculation. We have shown that the SNR improvement increases as the signal‐dependent index n of the dominant noise of the system increases, the improvement of intersymbol‐interference is large, and the optimum filter operates so as to eliminate first the dominant noise of the system. Moreover, it is shown that SNR of the optimum filter varies according to the value of the standard deviation of a signal waveform and has a certain maximum value when the standard deviation varies under the constant signal energy. the SNR improvement characteristics by this filter are compared to those of the full cosine roll‐off filter and the advantage of this filter is shown quantitatively.
Influences of circuit design on the characteristics of soft error in MOS dynamic RAMs
Authors: Yoshihara Tsutomu , Mashiko Koichiro , Takano Satoshi , Nakano Takao , Nagayama Yasuji 
Published: July 2007

AbstractThe circuit design of MOS dynamic RAM has a great influence on its fsoft errors; effects of capacity of the dummy cell, the word line potential, sensitivity of the sense amplifier, and their mutual timing, on soft errors were observed in accelerated tests with radioisotopes. the ratio of the dummy cell capacity to the memory cell capacity determines critical charges for “1” and “0,” the smaller of which controls the soft error rate. the soft error rate was reduced to one‐tenth by rainsing the word line potential before operation of the sense amplifier is improved by preserving sufficient time for grounding of its flip‐flop terminal and that the soft error rate is proportional to the bit line floating time. the error is minimized by adjusting properly the operation time of the sense amplifier.
Coherent characteristics of superconducting closed loop composed of Josephson junctions
Authors: Kobayashi Tadayuki , Kondo Nobuyoshi , Hamasaki Katsuyoshi , Yamashita Tsutomu 
Published: July 2007

AbstractWhen the impedance of a Josephson junction is too low, the elements are connected in series. We connected two arrays with N series elements of Josephson junctions each (denoted 2N‐JJ loop) and tried to find conditions for it to operate coherently by investigating voltage‐current curves. the computer simulation showed that coherent operation is easier with this circuit than with a series connection of the elements when the elements have different junction parameters. Pb‐alloy tunnel‐type junctions were produced which have N = 2 and 3, and we found that voltage steps generated by application of rf current with frequency F have a voltige interval corresponding to NF. This agrees with the simulation results and indicates coherent operation.
A 256 bit 12L RAM with a high‐voltage analog circuit
Authors: Kaneko Kenji , Okabe Takahiro , Maio Kenji , Nagata Minoru , Matsumoto Keizo 
Published: July 2007

AbstractRecently, it has become desirable for the analog‐digital LSI to have ROM, PLA, or RAM in addition to the conventional random logic circuits: I2L described in this paper is suitable for these purposes with its capability to be on‐chip with high‐voltage analog circuits. to suppress the circuit area increase which is the largest problem in coexistence with the high‐voltage devices, this RAM has a simplified peripheral circuit by an extensive use of I2L devices. Also, it has a circuit configuration which minimizes the number of device isolation regions. As operating features, it uses the memory cell read‐out transistor in the reverse mode during the signal read‐out in association with the simplification of the circuit configuration. Thus, it is possible to set up the power consumption according to its use. As a result of the fabrication of 256 bit RAM using the process technology for high‐voltage analog circuits (epitaxial layer: 1 ω cm, 10 μm, device‐isolation distance: 20 μm), npn transistor breakdown voltage BVCEO of 22 V, RAM area of 1.7 × 3.4 mm2, minimum access time 600 ns, and minimum write pulsewidth of 440 ns have been obtained.
Optimal design for two dimensional recursive digital filters
Authors: Fukuzawa Junji , Shimizu Kiyotaka 
Published: July 2007

AbstractTechniques are proposed for the design of two‐dimensional recursive filters approximating simultaneously prescribed specifications of magnitude and group delay. By treating the coefficients of the transfer function as decision variables, these approximation problems are formulated as (1) preference optimization problem and (2) optimization‐satisfaction problem, in order to obtain optimal transfer functions. In Case (1) an optimal preference solution is selected by a designer interactively from among a set of non‐inferior solutions of a 2‐object optimization problem for two performance indices of magnitude and group delay. In Case (2) the performance index for magnitude is optimized under the satisfaction condition so that the index of approximation error of group delay is always within a specified value. Finally, design examples from these two techniques are given.
Monolithic crystal filters exhibiting improved symmetric passband characteristics by means of two‐dimensional electrode arrangement
Authors: Sekimoto Hitoshi 
Published: July 2007

AbstractMany one‐dimensional arrangements have been used with only unilateral elastic coupling for electrode arrangement of a monolithic crystal filter (MCF). However, such an arrangement has the disadvantage that disturbance occurs within the passband and asymmetry of the characteristic increases with the specific bandwidth of the filter. to remedy this, the present paper proposes an MCF with two‐dimensional electrode arrangement to allow the bridged coupling to be zero. First, confirming that the bridged coupling between nonadjacent electrodes is a main factor disturbing the passband characteristic, a method of achieving zero bridged coupling between electrodes is provided by means of two‐dimensionally arranged electrodes. A design procedure for an MCF with two‐dimensionally arranged electrodes MCF is then introduced based on the M‐coupled equivalent circuit. Furthermore, a tandem arrangement with electrodes of different length is shown to be valid for suppression of skew symmetric modes necessarily excited in the two‐dimensional arrangement. Lastly, design of a 9‐resonator, tandem crystal MCF with 0.5% specific bandwidth is presented to decrease disturbance of the in‐band ripple and asymmetry of the passband and rising characteristics. Moreover, undesired response caused by the skew symmetric mode is seen to be suppressed sufficiently without difficulty in practical use.
Numerical analysis of plane wave scattering from a cylindrical scatterer with edge points by the mode matching method—the h‐wave case
Authors: Okuno Yoichi , Matsuda Toyonori , Yasuura Kamenosuke 
Published: July 2007

AbstractA mode matching algorithm with a second‐order smoothing process is proposed for accurate and efficient analysis of H‐wave scattering from a cylindrical body with edge points in the resonant region. the smoothing process is a method for transforming the boundary condition for the wave function to a smoother one by way of an indefinite integral. Since the smoothed condition can more easily be satisfied than the original boundary condition, convergence of the approximate wave function series by modal expansion can be accelerated by the smoothing process. In H‐type scattering problems, the first‐order indefinite integral can be evaluated by the conventional smoothing process without considering the existence of edge points. However, since convergence of the mode matching solution with the smoothing process is not fast enough, accurate solutions are difficult to obtain. Hence, second‐order smoothing is used in this paper. In this case, even for H‐type problems, the algorithm has to rely on the singular smoothing technique considering the edge point. Therefore, the algorithm becomes a mode matching technique in which the conventional smoothing and singular smoothing are combined. to find the effectiveness of the method, the problem of plane wave scattering by a conducting rectangular cylinder is numerically calculated. It is found that significant improvement is achieved in accuracy of the solution.
Burst‐error‐correction capability of cyclic codes
Authors: Tokiwa Kinichiroh , Kasahara Masan , Namekawa Toshihiko 
Published: July 2007

AbstractPreviously, the algebraic error‐correcting codes have usually been investigated independently for each error type [random, burst or compound]. the demand for high‐performance error‐correcting codes, however, has increased considerably due to the remarkable progress on many fields of digital communication. to meet this demand, a new research direction has been adopted by Matt‐Massey, Wang and the authors, reevaluating the burst‐error‐correction capability of the cyclic codes.In this paper an algorithm based on the generator matrix is proposed to analyze the burst‐error‐correction capability of cyclic codes. This algorithm appears particularly efficient in terms of the amount of computation. to apply the method in practice, a number of burst‐error‐correction cyclic codes has been investigated, and this paper presents some of the results obtained. Finally, a very interesting conjecture is given, which relates to the burst‐error‐correction capability of the maximum‐strength sequence codes.
A fast calculation algorithm for a parameter estimation of autoregressive and moving‐average model
Authors: Miyanaga Yoshikazu , Watanabe Hiroshi , Miki Nobuhiro , Nagai Nobuo 
Published: July 2007

AbstractLevinson's algorithm is one of the fast algorithms for estimating the parameters of an auto‐regressive model. Since this algorithm is recursive with respect to the order of a model, it is an effective method to obtain models of various orders when the true order is unknown. This paper proposes a fast algorithm to estimate the parameters of an autoregressive and a movingaverage model. the parameter estimation can be accomplished using a criterion based on the least square method. the problem of estimating autoregressive and moving‐average parameters from the criterion is reduced to that of solving a 2 × 2 block Toeplitz matrix. This method is an algorithm to solve this block Toeplitz matrix rapidly and it does not require the calculation of the inverse matrix. Also, it is recursive with respect to the order; the orders of an autoregressive model and a moving‐average model can be changed independently of each other. This method is an expansion of Levinson's algorithm and this paper shows the relationship between this method and Levinson's algorithm. Furthermore, properties of this method are discussed and as an example of its application, an experiment of model reduction is performed.
Frequency keeping algorithm for atomic reference frequency and clock supply
Authors: Kihara Masami , Jumonji Hiromichi 
Published: July 2007

AbstractA high‐accuracy cesium atomic oscillator is used as a clock for a digital communication network, in which, for instance, three cesium oscillators are used to take statistical average with the aid of a reference clock. We will discuss the algorithm for monitoring the frequency error by assuming a step frequency deviation. It has been confirmed that the algorithm satisfies the CCITT Time Interval Error requirements and that it switches to a normal cesium oscillator when frequency error is detected.
Separating capacity of a cascaded network of threshold elements
Authors: Takiyama Ryuzo 
Published: July 2007

AbstractThis paper discusses the information processing ability of the cascade network of threshold elements, which is a fundamental structure to realize a piecewise‐linear machine. the upper bounds for the number of dichotomies and the separating capacity are determined for that type of network, where theory of equivalent transformation from cascade network to two‐layered network is utilized positively. As a result, it is shown that the upper bound for the separating capacity of the cascade network consisting of k threshold elements is given by 2k(n + 1), where n is the dimension of the patterns to be classified.
Constitution of satellite switched TDMA network
Authors: Akiyama Minoru , Hirose Masatoshi 
Published: July 2007

AbstractIn constituting a satellite switched TDMA network with a multispot beam satellite it is necessary to determine an on‐board switching scheme and access scheme from an earth station, taking account of traffic intensity and number of stations in a beam, and to design an efficient system. This paper discusses the optimal design method, assuming that the satellite has both a microwave switch and a baseband switch. First, a traffic analysis method is shown for each switching scheme and access scheme, and the applicability of each scheme is investigated using the cost of an on‐board switch, etc., as criteria. Next, it is revealed to be about 20% effective in switch cost to use baseband switch channels as the final circuit to absorb overflow traffic from microwave switch channels.
Reversible predictive coding of continuous‐tone picture signals using block adaptive variable‐length codes — A scheme of reversible coding for picture data base
Authors: Saitoh Takahiro , Harashima Hiroshi , Miyakawa Hiroshi 
Published: July 2007

AbstractIn the picture data base the allowable distortion is dependent on the various uses for each picture signal. an efficient reversible coding for continuous‐tone picture signals, which does not increase the distortions of PCM original picture signals, is necessary to construct the picture data base efficiently. In most of the former proposed reversible coding schemes, the compression characteristic deteriorates remarkably as the number of picture signal gradations is increased. In this paper, a scheme of reversible predictive coding using block adaptive variable‐length codes is proposed for 8 bit/6 bit PCM continuous‐tone picture signals. A simple method of selecting the appropriate variable‐length code in every block based upon threshold logic, which is designed by means of numerical calculation, is shown to be able to achieve almost the same efficiency as in the optimum selection scheme. Besides, a method of adapting its block size is introduced to cope with the block size dependency of the compression characteristic. This coding scheme yields a performance advantage of approximately 0.2 ‐ 0.4 bit/pel for 8 bit PCM picture signals and 0.11 ‐ 0.17 bit/pel for 6 bit PCM picture signals over Rice Machine 1.
Experimental study of the relationship between the propagation distance and the polarization characteristics of whistlers
Authors: Okada Toshimi , Tanaka Yoshihito , Hayakawa Masashi , Iwai Akira , Shimakura Shin 
Published: July 2007

AbstractWideband (0‐8 kHz) measurements were performed for VLF whistlers at Moshiri (geomag. lat. 35°N) in Hokkaido in January, 1983 to investigate the relationship between polarization characteristics of whistlers and their propagation distance after the ionospheric transmission in the Earth‐ionosphere waveguide. the phase differences of the two signals of whistlers detected by orthogonal (E‐W and N‐S) loop antennas have been measured and the following results found: (1) the polarization of whistlers which penetrate the ionosphere close to the observing station is righthanded over a wide frequency range; and (2) some whistlers are found to have propagated over a distance of ∼1500 km. These whistlers exhibit a right‐handed polarization at some frequencies and a left‐handed polarization at other frequencies. However, the averaging of the observed polarizations over a wide frequency results in a nearly linear polarization; this agrees qualitatively with previous theoretical calculations by Crary.
Improvement of K‐band satellite link transmission capacity and availability by the transmitting power control
Authors: Egami Shunichiro 
Published: July 2007

AbstractTo cope with the rain attenuation in K‐band (quasi‐millimeter waveband) satellite communication, the effect of a transmitting power control scheme which controls adaptively the onboard transponder transmitting power toward each earth station according to the downlink rain attenuation, is clarified quantitatively. Also, the design of the FDMA satellite communication system with transmitting power control is made possible. Probability distribution of the downlink rain attenuation is used to represent each FDMA carrier transmitting power. the total transmitting power of the transponder is obtained as the sum of these FDMA carrier powers by using the central limit theorem. By the probability density function of this total power and the upper limit of this total power which is determined by the transponder maximum transmitting power and the output backoff, the maximum allocatable FDMA channels per transponder is derived. Further, the channel capacity of the overall system is calculated, taking account of rain attenuation distribution, regional differences of satellite antenna gain, and regional distribution of earth stations. By these procedures, the allocatable number of channels and the link availability are derived, and the design of the FDMA satellite communication systems with transmitting power control is made possible. As an example, considering Japanese CS‐2 satellite, the number of channels and link availability for 64 Kbps and 1.544 Mbps earth stations with antenna diameter 3 mø, are shown.
A synthesis of an active RC filter with reduced GB effect of operational amplifier
Authors: Watanabe Hiromichi , Hoshi Hideaki , Kikuchi Hisakazu 
Published: July 2007

AbstractIn synthesizing RC filters by simulation of LCR filters, the advantages are simplicity of synthesis and low element sensitivities. Ordinarily, the operational amplifiers used in this synthesis method are all considered to have ideal characteristics which hold only at low frequencies. Researches on the effect of the frequency characteristics of the operational amplifiers on the filter characteristics have been done for Biquad circuits in several cases but none at all for higher‐order active RC filters. In this paper, first, a synthesis method different from the conventional method is shown for a filter with finite zeros. Then a method for reducing the effect of the finite GB product on active RC filters is shown by contradicting the unnecessary phase‐rotating component of the operational amplifiers with the entire circuit, assuming that all operational amplifiers used in the filter have the same GB product. Furthermore, actual circuits are synthesized and experiments are performed. As a result, the effectiveness of the proposed compensation technique is shown by the fact that the frequency range for possible synthesis is extended. Finally, a synthesis method and experimental results are shown for a filter with all poles.
New planar magnetron system for ferromagnetic targets–Magnetic field distribution near the target surface
Authors: Takahashi Takakazu , Yoshida Junsaka , Takeda Fumio 
Published: July 2007

AbstractA new exposed pole‐type planar magnetron system for sputter deposition from ferromagnetic targets is proposed. Because the system uses a washer‐shaped target, both magnetic poles are exposed at the target surface. This allows great increase in the tangential magnetic field component at the target surface. We used three targets herein: the new washer‐shaped ferromagnetic (Fe), conventional nonmagnetic (A1), and ferromagnetic (Fe) targets. the magnetic field distribution over each target was measured as a function of the current through a field confinement solenoid coil. the tangential component of the magnetic flux density over the washer‐shaped Fe target was much larger than over the conventional ferromagnetic target, showing clearly the effect of the exposed poles. However, when compared with the nonmagnetic target, the tangential component is still small and the effect of the solenoid coil weak. the tangential component of the magnetic flux density is changed by the vector addition of the horizontal component of the solenoid coil field.
Interactive fuzzy decisionmaking for multiobjective nonlinear programming problems
Authors: Sakawa Masatoshi , Yumine Toru , Nango Yuji 
Published: July 2007

AbstractThis paper presents an interactive fuzzy decisionmaking method for the solution of multiobjective nonlinear programming problems. Considering the imprecise nature of the decision maker's judgments, we assume that for each of the objective functions, he has fuzzy goals expressed in words such as “x should be somewhat larger than a,” “y should be substantially less than b” or “z should be in the vicinity of c.” to quantify the fuzzy goals of the DM by eliciting the corresponding membership functions, we propose five types of membership functions: linear, exponential, hyperbolic, hyperbolic inverse and piecewise‐linear functions.Through the use of five types of membership functions, the fuzzy or imprecise goals of the decision maker are quantified. Then by selecting one of the three possible fuzzy strategies, the compromise solution of the decision maker can be derived from among (local) Pareto optimal solutions. On the basis of the proposed method, a time‐sharing computer program is written in FORTRAN and an illustrative numerical example is demonstrated together with the computer outputs.
Influence of an interfering second target on a certain amplitude‐comparison monopulse radar system
Authors: Endo Tetsuro , Suzuki Toshiaki 
Published: July 2007

AbstractThis paper examines angular tracking performance in an amplitude‐comparison non‐pulse tracking radar employing both AGC and phase synchronization (PLL) for the case where an interfering target as well as the main target are present within the beam of the tracking radar. the interfering target causes generation of an incorrect error output signal and the antenna boresight cannot be held on the main target. the effects of the interfering target are quite complex as they are dependent on the difference in Doppler frequencies of the two targets and on the bandwidths of the AGC and PLL systems. In this paper we calculate the error output using both the harmonic balance method and Galerkin's method for an arbitrary PLL bandwidth in combination with a narrowband AGC and a wideband AGC. From these results, we find that when the PLL has a comparatively narrow bandwidth the approximate analysis using the harmonic balance method gives sufficiently accurate results for practical application.