bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interpolated Z‐transform of the S‐parameter in the transient analysis of electrical networks
Authors: Kato Masami 
Published: July 2007

AbstractEarlier, the author proposed a method for transient analysis of the RLC passive electrical network. In that method, fundamental circuit elements constituting the electrical network such as lumped RLC elements, a branching point and a voltage source are represented in terms of the S‐parameter by introducing a fictitious transmission line. The S‐parameter which is a function of complex frequency s is then operated by the interpolated z‐transform, through which the network is expressed by the recursive equation in the time domain. However, this method has a drawback in that a fictitious transmission line which causes a time delay equivalent to one calculation time step must be introduced to interconnect the fundamental circuit components. This leads to errors in the calculated response waveforms, degrading the effectiveness of the proposed method. This paper reveals that by applying the matrix operation to the proposed analyzing method, the undesired time delay introduced by the fictitious transmission line can be eliminated completely. The method for determining the value of characteristic impedance of the fictitious transmission line which affects significantly the calculation accuracy is presented also. The relations between the various interpolated z‐transforms and difference equations, as well as the stability of each, are discussed.
Symbolic analysis of linear networks using matrix partition method and FFT algorithm
Authors: Takamura Hideo , Ohta Yuzo , Matsumoto Tadashi 
Published: July 2007

AbstractThis paper proposes an efficient method for calculating network functions of linear networks. It consists of an FFT algorithm to determine the coefficients of network functions and matrix partitioning to improve the efficiency of computation. As a measure of computational efficiency the number of multiplications σ for the method is introduced and it is shown that a considerable improvement can be made in reducing σ by permutations of rows and columns of the network coefficient matrix by using its canonical form.
Phase regeneration effect in mutual synchronization of oscillators
Authors: Kouno Tsutomu , Tanaka Mamoru 
Published: July 2007

AbstractMany reports have been published on the mutual synchronization of several oscillators. Most of them, however, deal with the case of oscillators of the same frequency, and no reports are known for the case when an external signal is supplied to synchronizing oscillators having different frequencies. This paper discusses the mutual synchronization and stability of two oscillators with frequency ratio of 1:2. Synchronization is discussed when a signal of almost the same frequency as the lower of the two oscillators is injected together with the phase response of the oscillator when a PM signal is injected. It is shown that mutually synchronizing oscillators exhibit a phase regeneration effect. Furthermore, it is shown experimentally that there is a phase regeneration effect and an accompanying noise suppression.
A study of reflected light effects on the modulation characteristics of semiconductor laser module for single‐mode fiber transmission
Authors: Sugie Toshihiko , Saruwatari Masatoshi 
Published: July 2007

AbstractOperation of a laser diode (LD) module for a single‐mode fiber (SMF) is affected by reflection from coupling elements, in particular, from the SMF endface. For an LD module employing a cylindrical lens method, it has been determined that the phase of the reflected beam fluctuates with temperature, which causes fluctuation in the modulated waveform. It was also found that LD modules are easily subject to fluctuation if an external cavity constructed by the LD and SMF endface has a larger mode spacing than that for the LD cavity. LD modules with anti‐reflection characteristics have been fabricated using a combination of two confocal‐lenses with large separation between the LD and the SMF. These modules exhibit stable operation against temperature variation.
Analog source digitization—effects of sampling and quantizing
Authors: Iikura Yoshikazu 
Published: July 2007

AbstractThe theoretical limit of data compression concerning an analog source is given by Kolmogorov's ϵ‐entropy. But in practical systems in which analog signals are transmitted digitally the sampling and quantizing processes are indispensable. In this paper the ϵ‐entropy of the band‐limited stationary Gaussian signal is obtained and it is shown by use of sampling theorem that it has the same value as in the case of a uniformly sampled signal (stationary Gaussian series). By adding the error due to band‐limiting (sampling error) and the redundancy residue to the quantizing to the ϵ‐entropy and under the restrictions of sampling and quantizing, the relation between mean‐square‐error and transmission rate (speed) can be formulated. By adjusting sampling and quantizing intervals, the data compression limits to such a system become clear.
High‐speed continuous‐phase FSK modulation and demodulation system
Authors: Morihiro Yoshiteru , Furuya Norio , Fuketas Hiroaki 
Published: July 2007

AbstractThe continuous‐phase FSK system is a remarkably beneficial digital modulation and demodulation system due to its good transmission performance over satellite communication circuits and others which has some band restriction elements and nonlinear components. However, no report has been made yet on its practical circuit construction or design method. Here, studies are made on practical circuit structure based on the principle of modulation and demodulation in connection with the binary continuous phase FSK, sometimes called MSK, FFSK, etc., with 0.5 modulation index. Presentation is made for the circuit structures for a modulation system by using the off‐set‐bipolar‐modulation‐and‐synthesis, and for a demodulation system by using the synchronous‐detective‐wave‐coherent‐detection and 2‐steps‐up carrier synchronous system. These are applied appropriately to high‐speed modulation and demodulation over several hundred M bit/s in the radio frequency range in or beyond the microwave frequency. As for the coherent detection, quantitative study is made on impairment figures due to the optimum reception band restriction over the Gaussian transmission system, phase errors of regenerated carriers, and timing discrimination errors. It is concluded that its error characteristics are almost equal to those of the optimum detection system at the BT product of reception, 0.5‐0.6, and its phase error takes a deterioration figure of the two‐phase PSK system. Furthermore, experiments were conducted on modulation and demodulation at the carrier frequency of 1.7 GHz and the data transferring speed of 100 M bit/s to confirm the basic characteristics and theoretical results. The result showed that it could have satisfactory features for practical applications.
Low loss 4x4 optical switching network
Authors: Fujii Yohji , Minowa Jun‐Ichiro , Nagatas Yoichi , Aoyama Tsutomu , Dois Kikuo 
Published: July 2007

AbstractA 4 × 4 optical switching network was realized which has a low insertion loss and good switching repeatability. Practical optical switching networks are in great demand for optical fiber communication and information processing systems of higher grade and more versatility. This paper first classifies the application ranges of optical switches and then discusses the technical levels needed for realization of optical switches for each range. Also, the method for constructing the optical switching networks is discussed. Based on the discussions, the method is obtained for designing optical switches and switching networks which realize loss loss and high switching repeatability. Characteristics of the prototype 4 × 4 optical switching network are: (1) low insertion loss (0.3‐1.3 dB); (2) good switching repeatability (less than 0.06 dB); and (3) high cross‐talk attenuation (more than 55 dB). From the present results, it is found possible to realize a large‐scale optical switching network of 100 × 100.
Properties and synthesis of distributed‐parameter circuits composed of resistors and unit elements
Authors: Saito Kentaro , Nemoto Yoshiaki , Satos Risaburo 
Published: July 2007

AbstractThe circuit composed of alternatively cascaded resistors and unit elements is the most fundamental among distributed‐parameter circuits containing resistors. The necessary and sufficient conditions for realization of the driving point immittance in which element parameters satisfy given relations have been reported. As for R (resistor)‐terminated circuits composed of alternatively cascaded n resistors Rj's and characteristic impedances Zj's, there are three types of circuit configurations: 1) R1 > Z1, Rν+1 > Zν + Zν+1, R > Zn, 2) R1 = Z1, R̄ν+1 = Zν + Zν+1, R = Zn; 3) R1 < Z1, Rν+1 < Zν + Zν+1, R < Zn (ν = 1, 2, …, n‐1). For 1) the realization condition was reported. For 2) and 3), the circuit properties and synthesis methods have not yet been investigated. In this paper the driving point immittance for 2) is derived in case that the element parameters satisfy given relations. This immittance function is that for the RL or RC circuit which is degenerated with respect to Richard's variable p. A new synthesis method which differs from 1) is proposed.
Equivalent circuits of binomial‐form nonuniform transmission lines and their application
Authors: Kobayashi Kunikatsu , Nemoto Yoshiaki , Satos Risaburo 
Published: July 2007

AbstractAmong various nonuniform distributed‐parameter transmission lines, the exponential line and binomial line can be analyzed by obtaining the rigorous solutions of the telegraph equation. The exponential line in which the line parameters change exponentially has been studied in the past, but the binomial line has not yet been studied systematically because the rigorous solutions for the voltage and current distributions differ depending on the characteristic impedance. In this paper, the rigorous solution of the telegraph equation for 2nth‐order binomial lines is derived and its equivalent circuit is constructed by a cascade connection of uniform distributed‐parameter lines, lumped reactance elements and ideal transformers. Further, the binomial line is made equivalent to the exponential line by equating the characteristic impedances of both lines at the input and output terminals and by letting the order n of the binomial line be infinite. Finally, as an application example, the high‐pass filter consisting of the series lumped capacitance and uniform distributed‐parameter line is constructed by the quadratic binomial lines and series lumped capacitances.
A simulation‐type RC active filter using a negative impedance converter
Authors: Ishibashi Yukio 
Published: July 2007

AbstractThe LC simulation‐type active RC filter has a lower element sensitivity than the cascade active RC filter. This paper proposes a method of realizing the LC simulation type active RC filter which is suitable for the bandpass filter with finite number of poles. The resistor is converted to a parallel circuit of ‐L, ‐C and ‐R by the frequency‐dependent NIC composed of two resistances, two capacitances and one op‐amp. Then the LC filter is realized by converting all elements to negative elements. The sixth‐order simultaneous Chebyshev filter is constructed. The test result indicates the effectiveness of the present method. The present method requires smaller number of elements (particularly, active elements) than any other methods.
Analysis of loop antenna with circular reflector and its properties
Authors: Iwashige Jiro 
Published: July 2007

AbstractThe method of equivalent edge currents is applied to derive diffraction fields by an edge of a cone conductor. Geometrical‐optical fields (direct wave + reflected wave) are added to the diffraction fields and both fields are Fourier analyzed to find current distirbutions and input impedance. Radiation pattern and power gain are obtained in terms of diffraction coefficients derived by Kouyoumjian et al. Calculations are made mainly for a one‐wavelength loop antenna and the effects of the disk reflector diameter and wedge angle are clarified. The power gain is 1 dB larger than that of an infinite plane reflector. Theoretical results generally agree with observations.
A validation method of communication protocols free from data block loss and duplication
Authors: Yoshida Yutaka , Nomura Masayuki , Tanakas Yoshikazu 
Published: July 2007

AbstractThis paper presents a validation method of communication protocols. Many validation methods of communication protocols have been reported, mostly aiming at validating only the deadlock. The method will provide a means of discriminating the deadlock, data loss and duplication. First, the operation of two terminals which are communicating with each other according to a protocol with one block sending at one time (the most widely applied procedure) is defined as an automaton of two sets of terminals or terminal automaton. Second, the communication system is described as another automaton (communication automaton) composed of the former automations, with due regard to error characteristics of transmission paths caused by noise. Third, the state transition diagram of the communication automaton is utilized to provide the discrimination method. We will apply it to the JIS standard basic procedure and demonstrate its usefulness.
Magnetostatic wave delay lines using an inhomogeneously magnetized Yig Slab
Authors: Masaoka Yoshihiko , Tsutsumi Makoto , Ohira Takoshi , Kumagais Nobuaki 
Published: July 2007

AbstractA new delay line for magnetostatic wave is proposed. The line consists of a ridge magnetic pole piece. Theoretical results are compared with observed ones for a (110)‐cut YIG slab. Dispersion of group delay is improved by a factor of 2 to 3 compared with an ordinary delay line using a planar pole piece, and the propagation loss is as small as 25 dB, that is, close to loss of bulk propagation in YIG.
Difference‐frequency generation in three‐dimensional linbo3 optical waveguide
Authors: Uesugi Naoshi 
Published: July 2007

AbstractSince an optical waveguide can carry the light wave of high power density, very efficient nonlinear optical devices may be realized using the optical waveguide. Second harmonic generation in an optical waveguide has been reported. However, little has been known on difference‐frequency generation. This paper discusses generation of difference‐frequency signal in a three‐dimensional LiNbO3 optical waveguide which utilizes temperature variations of birefringence of LiNbO3 as a phase matching mechanism. From calculations of phase matching conditions, tuning characteristics and conversion efficiency of the difference‐frequency generation, it is found that the phase matching condition can be satisfied readily over a wide wavelength region and that the conversion efficiency in a 1‐cm long optical waveguide reaches a few percent with 100 mW pumping input. Further, using a three‐dimensional Ti‐diffused LiNbO3 waveguide, we generated difference‐frequency signals of a Rhodamine 6 G dye laser and a Nd:YAG laser. By changing the wavelength of the dye laser and the temperature of the optical waveguide, we generated difference‐frequency signals from 1.035 μm to 1.19 μm. At 1.035 μm wavelength, we generated 2.4 μW signals from the dye laser input of 70 mW and the Nd:YAG laser input of 1.7 mW.
Minimax design of model‐following control system
Authors: Yahagi Takashi 
Published: July 2007

AbstractThis paper presents a method for the design of linear regulators subject t o minimum performance. This regulator is designed such that it follows the reference model which exhibits desirable transient response. If the quadratic performance function is used for the transient response errors of the control system and the reference model, the optimum solution depends on the in it ial state of the control system. Such initial ‐ state dependency must be eliminated in the design of regulators. A minimax design for the model‐following control system i s described for cases with and without compensators with performance functions, the calculation for obtaining the optimum solution becomes complicated, i. e, it becomes impossible to obtain the minimax solution by directly solving the necessary condition of the optimum solution. This paper proposes a numerical algorithm by which the minimax solution can readily be attained.
Improvement of front‐to‐back ratio by choke loaded at edge of parabolic antenna
Authors: Kaneki Toshiyuki 
Published: July 2007

AbstractWhen the parabolic antenna is loaded in its periphery with a choke, the electric current inside the reflector can be suppressed so as to improve the front‐to‐back ratio. This paper establishes the function of the choke and presents qualitatively its effect. A primary radiator used is a shot radiator and the practical antenna is represented by a two‐dimensional model to simplify the treatment in which the function of the choke can be represented by a single integral equation. After solving the integral equation, the choke function and its equivalent magnetic current are obtained, the pattern of the antenna loaded with choke can be calculated from the combined fields due to the magnetic current and the primary radiator, and the results are compared with the measurement. For example, for the case of an antenna 40 cm in diameter loaded by a 3 mm choke at 12 GHz, 5 dB improvement in front‐to‐back ratio can be achieved. Also shown is that the magnetic field component of the slot contributes about 1 dB to the effect.
A finite element model for the inverse problem in electrocardiography
Authors: Murai Tadakuni , Kagawa Yukio 
Published: July 2007

AbstractA finite element model suitable for solving the inverse problem of electrocardiography is proposed. The body field is divided into two regions, the region without current source which is exterior to the heart and the cardiac region where the current sources are present. For the former region, the finite elements are so constructed that the discretized transfer matrix between the body surface nodes and the epicardial nodes can be uniquely determined. For the cardiac region, the treatment is basically the same as the former in the sense that the number of nodes assigned to the cardiac current sources within the heart is taken to be identical to that of the epicardial nodes. This arrangement provides a unique solution, though special devices for high‐order elements must be carefully arranged. Transfer characteristics that relate the surface potentials to the current sources are thus achieved.
Photo‐excited DLTS: Measurement of minority carrier traps
Authors: Takikawa Masahiko , Ikoma Toshiaki 
Published: July 2007

AbstractThe “photo‐excited” DLTS using light with energy less than the bandgap gives different spectra from the majority carrier DLTS spectra. This is because the transient response magnitude P(T) depends on temperature and the conventional DLTS analytical method cannot give correct activation energy Et and capture cross‐section σt for the deep levels. Herein the temperature‐dependence of P(T) is considered and the methods for obtaining Et and σt for minority carrier traps from the photo‐excited DLTS spectra have been proposed. These methods have been applied and found suitable to the derivation of Et and σt of the Fe‐level in a GaAs p+n junction and by comparing the results with those from the injection DLTS, its appropriateness is confirmed. Also the detection sensitivity and measurable levels are given as functions of the incident light energy. When these are compared and checked with the conventional DLTS method, the photo‐excited DLTS has been established as a measurement approach of minority carrier traps.
A new switched‐capacitor transformer and its analysis
Authors: Inoue Takahiro , Ueno Fumio , Oota Ichirou 
Published: July 2007

AbstractIC realization of a switched‐capacitor transformer with in integer turn ratios, based on alternating and switching series and parallel‐connections of capacitors is presented. The circuit consists of n capacitors and 3n+1 MOS FET switches. This circuit is advantageous in that it has monolithic IC capability, DC voltage step‐up and step‐down are possible and non‐grounding can be achieved. It is thus useful for the integration of difficult circuits containing transformers. In this paper theoretical analyses are given for the case of ideal capacitors and switches, and for the case of non‐zero stray capacitance and on‐resistance. The effects of the on‐resistance of switches on the transfer characteristics of the transformer on the operating frequency range, allowable input level, element sensitivity and temperature characteristics are shown both theoretically and experimentally. As an example of applications, the test of a first‐order all‐pass filter is presented. The test used two 1,000pF capacitors and MOS FET switches; voltage step‐up and step‐down in the range from DC to 100 kHz were demonstrated. In this case the maximum allowable input level is about 0.5V and stability is ensured at temperatures from −20 to 80°C.
Experiment of a hybrid‐type implementation of an adaptive array under directional constraint
Authors: Takao Kazuaki , Kawamura Osamu , Komiyama Koji , Hashimoto Kozo , Kimura Iwane 
Published: July 2007

AbstractThe VHF 2‐channel adaptive antenna system was constructed by means of the output minimization under directional constraint, and its performance was evaluated. In the field experiment, the preservation of the desired signal and elimination of the interference wave were confirmed. The system adopts a hybrid‐type implementation of the analog processing part and digital processing part. The correlation between the input and output is calculated by the analog portion and the remaining computation is made by the digital portion. The time variation of the desired signal and the interference component, the frequency spectra of the output and the antenna directivity were measured in the laboratory. When the desired signal and the interference wave have the common frequency band, the interference wave can be suppressed sufficiently by this system if their incoming directions differ. The signal‐to‐interference ratio was above 30 dB. In the field experiment, we obtained 20 dB.
Circuit design of large scale dynamic MOS RAM with scaling relationships
Authors: Nagayama Yasuji , Yoshihara Tsutomu , Nakano Takao , Gamou Yoshimi 
Published: July 2007

AbstractFurther integration of the dynamic MOS RAM (MOS(D)RAM) depends on improvements in fabrication and in device and circuit techniques. To attain better operating characteristics and stable operation for large‐scale integration, it is necessary to establish a design approach that combines all of these techniques. This paper describes such an approach. First, the coefficientmdefining the sensitivity, read‐voltage and the operating region of the sense circuit is established and the design guidelines of the sense circuit are then derived. Analysis of the coefficientmshows that variations in device parameters attributable to processing accuracy significantly affect the stability of the large‐scale MOS(D)RAM operation. To obtain a wide operating region for the 64K MOS(D)RAM, the 128 refresh method is shown to be advantageous. Next, based on the design guidelines it is shown experimentally that 64KMOS(D)RAM can be fabricated with wide upper‐ and lower‐operating limits and that the design approach to large‐scale MOS(D)RAM using the fine‐pattern fabrication technique presented here is indeed valid.