bluuebunny/crossref_metadata_2025 huggingface dataset:
The correlation effects on service control point response time
Authors: Wey Jyhi‐Kong , Sun Lir‐Fang , Yang Wei‐Pang
Published: July 2007

As the centralized database for the integration across multiple wireless tiers and wireline access, traffic design considerations for SCP performance measurement are of great important in the personal communications era. By neglecting the effect of disk access time, the SCP response time R includes the SCP processing time P and signalling link delay L only. A bivariate normal distribution has been proposed for modelling (P, L) such that some statistical estimations of L given P can be conveniently obtained in different combination of SCP processing load and link utilization. Further, the correlation effects of (P, L| P=p) on R are investigated. After a Tukey one degree of freedom test with one observation of μL|P=p per treatment (n=1) under different normalized processing times and correlations, the two‐factor ANOVA model becomes an interaction model without pure error effects due to the computed F* values being significantly greater than the critical F (0.95; 1, 11). Besides, rejection threshold criteria of SCP response time with minimum loss rate (0.01 per cent) of messages are proposed to ensure a good service quality of SCP.
Congestion detection based on rate and buffer occupancy measurements
Authors: Cheng T. H. , Cheah K. L. , Oh S. H.
Published: July 2007

Based on traffic simulation studies at an FDDI/BISDN gateway, this paper evaluates the relative merits of using rate and buffer occupancy measurements in the detection of congestion and the use of such measures to provide simple bandwidth management. In addition, a detection scheme based on using both rate and buffer occupancy measurement is recommended as it combines the advantages of both schemes and provides more reliable performance over a range of bursty traffic.
Analysis of acoustic prism couplers for rayleigh and lamb waves
Authors: Takeuchi Masao , Shimizus Hiroshi
Published: July 2007

The prism coupler has long been used for excitations of Rayleigh and Lamb waves. Since analysis is lacking in the leaky wave phenomenon on the guided wave path due to the prism perturbation, many problems are not explained. In this paper, the solid and liquid prism couplers are analyzed by the leaky wave concept and modeconversion theory, the following problems are clarified: the mode conversion efficiency expected to be obtained in theory, the coupling length between the prism and the guided wave path as related to the mode‐conversion efficiency, the difference between the p‐ and sv‐wave in the solid prism coupler, the effect of the liquid couplant, and the effect of the absorption loss in the prism material. Three of the universal diagrams are also provided. It is confirmed that the measured and theoretical available conversion efficiency for the Rayleigh wave transducer consisting of the bulk wave transducer are in good agreement.
Deficient decoding for convolutional codes
Authors: Hashimoto Takeshi , Arimotos Suguru
Published: July 2007

Tree codes are so important that they often appear in information theory. Highly reliable coding systems may be realized in view of their sequential decoding. While a number of analyses have been made of the probability of error in sequential decoding and of the amount of calculation required for decoding only a few analyses are presently available on the various characteristics when sequential decoding is applied to convolutional codes. Here, we shall evaluate the so‐called deficient decoding that occurs when convolutional codes are sequentially decoded by decoders with finite decoding speeds. The evaluation will be based on the findings of recent studies on the amount of calculation required for the sequential convolutional codes.
Theoretical analysis of a grounded monopole antenna
Authors: Nakagawa Kinsaku , Inagaki Naoki
Published: July 2007

The grounded monopole antenna without earthing used as a basic ground antenna is analyzed by the moment method. Its current distribution, input impedance, directivity and antenna efficiency as functions of earth dielectric constant and conductivity, antenna height and frequency are obtained. The generalized impedance can be made calculable even for the case of nonzero current at the end of the antenna. Numerical results show that the current distribution varies subtly with the earth electrical properties. The small‐area effect of earth is clarified. For the quarter‐wave monopole antenna, the efficiency increases with decreasing frequency but it is below 50% for typical earth conditions when the frequency is above 0.1 MHz. For large antenna height, the antenna efficiency is large, the maximum directivity becomes closer to the horizon, but at 0.6 wavelength the radiation along the sky direction is strong, and the fact that at 0.53 wavelength it is used as an end‐firing antenna can be explained. It is shown that the antenna efficiency becomes lowest when the earth displacement and conduction currents are equal.
Analysis of tapered optical slab waveguides with hypothetical boundaries
Authors: Sawa Shinnosuke , Onos Kazuo , Odaka Hironobu , Sakuma Masaki
Published: July 2007

It is proposed that the tapered optical waveguide be analyzed by the nonopen system treatment method in which hypothetical boundary walls (electric or magnetic walls) are added to the exterior of the open‐type waveguides. In addition, the step‐approximation method is used for analyzing the single‐mode slab optical waveguide taper. It is shown here that the basic properties of tapers, in which the TE mode propagates, for example, the radiation power and pattern as well as power distribution on the waveguide cross section, can be obtained. The conditions that allow the open‐type tapered waveguide to be treated as a nonopen system are investigated numerically. This paper shows that for long tapers, the hypothetical walls must be farther away from the waveguide, whereas for obtaining the radiation power and pattern, as well as the radiation field, these walls do not have to be separated considerably from the waveguide. Moreover, it is seen that not all the propagating modes need to be used in calculations; even if only about 10 modes are chosen, the radiation power and field distribution can be obtained without loss of accuracy and within a short computation time.
Active rc synthesis of arbitrary admittance matrix
Authors: Matsumoto Tadashi , Takahashi Tohru , Takahashis Shin‐Ichi
Published: July 2007

It is shown that any p × p admittance matrix can be realized using at most 4 p operational amplifiers regardless of the Mac Millan order by means of reactance extraction applied to comrade matrix and generalized Luenberger form. In the comrade matrix, there is a clear relation between elements and polynomial series of elements. Once a set of polynomial series and characteristic polynomials are determined, the comrade matrix can be determined uniquely. For oneport network, the conductance matrix obtained by reactance extraction can be related to the RC ladder‐type network with the current feedback if proper polynomial is selected. The realization method for the one‐port network can be extended to the multiport network by using the generalized Luenberger form in which the diagonal portion is a comrade matrix.
High‐order digital phase‐locked loop using integrators in pulse frequency modulation system
Authors: Iritani Tadamitsu , Kinouchi Yohsuke , Ushitas Tomiyuki
Published: July 2007

The carrier‐tracking loop that employs a digital phase‐locked loop (DPLL) can be made very stable in operation. From the signal with frequency offset or Doppler shift, carrier tracking without steady‐state phase error, requires the use of higher‐ (greater than second) order DPLLs. The first‐order DPLL published earlier provides a linear operation characteristic in a wide range besides being improved for digitalization of the past analog PLL. The output phase of this first order DPLL can be controlled externally. Combining the first‐order DPLL with a variable‐phase PFM integrator, and controlling the phase of each, higher‐order DPLLs are realized. Five types of second‐order DPLL's are built and analyzed. Comparison with analog PLL shows that the closed‐loop transfer function can be approximately linearly to that of an analog PLL. The range of synchronization and time of synchronization are of the same order in the case of perfect second‐order. However, in the case of imperfect second‐order systems, the DPLL is more superior. Further, third‐order DPLL's are analyzed and constructed and a method of realizing nth‐order DPLL is established.
Radar reflectors with controllable reflection
Authors: Onoe Morio , Hasebe Nozomu , Zamas Tomoyuki
Published: July 2007

Radar reflectors have been used to increase the reflectivity of small vessels and navigation guides for easy detection. If the reflectivity is controllable by some electrical or mechanical means, then a passive telemetry would be possible, which transfers some information from the site of a target to a radar station. This paper presents a controllable radar reflector, which consists of an array of resonant dipoles or slots combined with a reflecting plate. When the array of slots is placed at the focal plane of a Luneberg lens, an electrical or mechanical reflectivity modulation of more than 10 dB is obtained for wide angle of incidence in laboratory and field experiments.

Additional features, such as sturdy structure, slight scattering, wide bandwidth (more than 4 percent at the modulation of 10 dB), easy construction and adjustment, and the optional ability of mechanical control make the slots array practical.
Limited scan characteristics of short backfire dipole phased arrays for is radars
Authors: Tokumaru Shinobu , Nakanishi Hideki
Published: July 2007

The basic characteristics of short backfire dipole phased arrays for use in the IS radar are analyzed. The array must have the active independence 50 ω in the scanning range and element pattern less than ‐10 dB for the observation angle above 60°. Some of the arrays in a rectangular arrangement with element interval 0.75 λ, 0.8 λ, and 0. 85 λ satisfy the above requirement, but the arrays in a twisted rectangular arrangement can not satisfy this requirement. The frequency characteristics of phased arrays are also discussed.
Learning routing applied to large scale packet–switched communication networks
Authors: Kuribayashi Shin‐Ichi , Nakamura Tadao , Satos Risaburo
Published: July 2007

Learning routing is introduced to large‐scale communication network to compensate the lack of a priori information on the network behavior. Learning routing consists of learning automaton as a learning controller placed at each network node. This learning automaton makes decision on routes for packets which are the basic unit of data to be transmitted through the network. Using learning automaton we propose two routing methods, LRI and LRI, which are basically reinforcement methods for the learning automaton. The effectiveness of these proposed methods is shown by means of simulation on a concrete network topology.
An analysis of thin‐film resistance networks with two resistive materials
Authors: Iwakura Hiroshi , Arakawas Teruaki
Published: July 2007

In designing the planar resistor and attenuator using uniform resistive media, if the electrode and structural dimension ratio are extremely small or large, the design is not realizable. In such cases, the realizable design range can be enlarged by using two kinds of resistive media. However, the resistance value can be obtained by solving nonuniform boundary value problems. In this paper, we report an approximate method for evaluating resistances using two kinds of resistive media. Further, the design method for composite thin‐film resistance and three‐port attenuator is proposed based on the analysis result and conformal mapping. The result of the analysis agrees with the experiment within the practical accuracy.
Effect of the circuit of second‐harmonic frequency on impatt oscillators
Authors: Shindo Yoichi , Okamuras Sogo
Published: July 2007

The effects of a second harmonic resonance circuit on IMPATT oscillator characteristics have been investigated. The admittance of an IMPATT diode is measured using an injection locking method simultaneously at the fundamental and second harmonic frequencies. A computer analysis, approximating the p+nn+ IMPATT structure with a Read diode, is carried out and the results are compared with the experiment. The theory agrees well with the experiment and has revealed characteristics of IMPATT diodes in the presence of an ac voltage component at second harmonic frequency. It is found that the negative conductance at the fundamental frequency is increased by properly selecting the load admittance at the second harmonic frequency. Characteristics of an IMPATT oscillator with a second harmonic resonance circuit at microwave and millimeter wave frequencies then are examined based on the computer simulation. The output power at the fundamental frequency varies over 10 dB when the second harmonic circuit conditions are varied near the resonance condition. The output power at fundamental frequency can be made a few decibels higher for optimized admittance at the second harmonic circuit than under off‐resonance conditions. Considerable output power at the second harmonic frequency is obtained under the above resonance conditions, and is described in detail.
Superconducting cavity stabilized oscillators by self‐injection locking
Authors: Komiyama Bokuji , Yasudas Yoshiyuki
Published: July 2007

In the superconducting cavity stabilized oscillator (SCO), which has extremely high‐frequency stability, the power input to the superconducting cavity (SC) must be minimized since the energy stored in the SC causes a shift in the resonance frequency away from its value at zero stored energy due to the electromagnetic radiation pressure and nonlinear surface reactance. Therefore, in the SCO with self‐injection locking, a loosely coupled directional coupler is used to couple a free running oscillator to an SC. This paper describes the design of self‐injection‐locked SCO's.

The effects on frequency stability of the SC coupling factor and electrical line length between the SC and oscillating device are discussed. Oscillation frequency is given as a function of electrical line length. Optimum line length is discussed and the stability criteria for the oscillating device are derived. Based on this design consideration, an X‐band Gunn effect oscillator is stabilized. The SC is fabricated from solid Nb and has an unloaded Q‐factor of 6.7 × 106. The noise floor of frequency stability as low as 8.5 × 10‐11 has been obtained.
An improvement of the facsimile data compression factor by loosening the hardware complexity condition
Authors: Ueno Yutaka , Ono Fumitaka , Semasa Takayoshi , Ohnishis Ryoichi
Published: July 2007

In a previous paper, the authors introduced a predictive partition coding scheme—CLAPEL—for the optimization of facsimile data compression using the correlation of neighboring picture elements (pels). In the 'present paper the relationship between the design parameters associated with the hardware scale and the compression factor is investigated. The input documents used in the simulation are the eight test documents recommended by the CCITT. The design parameters are varied; and the corresponding variations in the conditional entropy, the (compression) preserving factor, and the coding efficiency are observed. It is found that within the practical range of hardware scale, the preserving factor depends only on the number of modes if the number of reference pels is increased, and that the adaptive processing is not necessary during the predictive transformation. Several new coding schemes are examined in the examples which indicate that the coding efficiency has a tendency to decrease as the hardware parameters grow. Thus, the relationship between the hardware design parameters and the compression factor is clarified. The objective of this paper is to investigate the data compression factor without considering the processing times of the input and output devices.
Computer simulation for self‐consistent eb proximity effect correction
Authors: Sugiyama Naoshi
Published: July 2007

This paper describes a computer algorithm to self‐consistently determine exposure correction for the proximity effect which has been recognized to be indispensable in electron‐beam exposure. The usefulness of this method is demonstrated by computer simulation. The previously proposed successive determination of proximity effect correction is not self‐consistent. However, the present method is not only self‐consistent, but also capable of maintaining pattern symmetry. Coupled equations for irradiation intensities to be directed to various figures must be solved. These equations are over‐determined in many cases, and therefore, the least‐square solution with the minimum norm is employed. Since the solution has to be discretized with upper and lower bounds, the problem constitutes a quadratic programming. A modified successive overrelaxation (SOR) method is used to consider the large sparse matrices.
Formulation for the equation describing a passive switched‐capacitor network
Authors: Tanaka Mamoru , Moris Shinsaku
Published: July 2007

The coefficient matrices of the describing equations for the passive switched‐capacitor (SC) networks consisting of periodically open/closed switches, capacitors and independent voltage sources can be obtained by using new topological formulas. These topological formulas are derived when the open/close resistances (R, r) of the switch are taken into account, by taking the limit of (R, r) → (χ, 0) for the coefficient matrices of the Laplace‐transformed differential state equations describing the networks. This method differs from the previously used nodal method, in that it does not need matrix inversion calculation so as to express the coefficient matrices in terms of powers of matrices which are simply obtained topologically. It is extremely useful for analysis of the large‐scale passive SC networks.
A digital phase‐locked loop with and filter
Authors: Kurita Taiichiro , Yokoyama Masaki , Mori Shinsaku , Ozawa Shinji
Published: July 2007

In general, it is known that if the stationary characteristics of a PPL, phase‐locked loop, are improved, its transient response characteristics are deteriorated, while if the transient response characteristics are improved, its stationary characteristics are deteriorated. The DPLL, digital PLL, is not an exception in regards to the features.

Here, we will realize a loop which is superior both in the effective phase error and the average transient response time compared with conventional DPLL with less deterioration of the average transient response time caused by improved effective phase error, due to inserting AND filter to the conventional binary quantized DPLL. The characteristics of the proposed loop are analyzed theoretically by use of the Markov chain and confirmed to be identical by computer simulation. These results prove that the proposed loop has better characteristics than the conventional ones.
Linbo3‐ge acoustooptic modulator at 10.6 μ m
Authors: Yasuoka Yoshizumi , Takahashi Terumasa , Miyatas Toyo‐O
Published: July 2007

By use of LiNbO3 and Ge, a 10.6 μm CO2 laser acoustooptic modulator device is fabricated and its acousto‐ and optical‐modulation characteristics are investigated. When epoxy‐type conductive adhesive is applied to LiNbO3 and Ge and the device is annealed thermally at 100° C for more than 20 hours, and the acoustooptic modulator device gives the diffraction efficiency predicted in theory according to the device material and shape. The device yields 8% diffraction efficiency at a driving power of 1W, and 0.11 μs rise time for the case of 1 mm laser beam diameter; when operated below 2W driving power it yields stable operation for a long time.
Algorithm for finding the zeros of very‐high‐degree fir filters using the finite bit method
Authors: Yoshikawa Toshinori , Mitani Masaaki
Published: July 2007

The communication FIR filters are used in a cascade configuration of several ten degrees to several hundred degrees which require the solution of very‐high‐degree algebraic equations for the analysis. The conventional algorithms enable algebraic equations of about 200 degrees to be solved. This paper proposes a novel algorithm which solves accurately and effectively very‐high‐degree algebraic equations. This algorithm utilizes the finite bit method and is not subject to overflow and underflow. This algorithm is independent of the initial values and can solve algebraic equations of as high as 1000 degrees. The computation time is proportional to the square of the degree.
Analysis of the simultaneous transmission system for a picture and narrowband signals
Authors: Morimoto Sei
Published: July 2007

Systematic investigation is made on the noise generated in an FM transmission system for the simultaneous transmission of wideband picture signals and narrowband voice and data facsimile signals. In thermal noise analysis, tradeoffs are carried out between the noise characteristics resulting due to the methods of modulation and multiplexing of narrowband signals. Methods of handling the cross noise and distortion noise, caused by narrowband signals are described. As far as the methods of modulation of the subcarrier wave which corresponds to the narrowband signal are concerned, AM, FM and PSK are considered. The FM and PSK are taken as the focus of present discussion. As far as the distorition noise is concerned, besides the noise of narrowband signal, it is necessary to account for the noise that drops into the picture signal band. The reason for the former is considered mainly to be the differential gain (DG), and the reason for the latter varies depending on the dropping frequency of the noise. The computed values agree very well with the experimental characteristics.

For the medium of transmission of multiple signals that include wideband picture signals, the frequency modulation formula has an advantage and the probability of its future development is large.
A new method for enhancing the output energy of pulsed hf chemical lasers
Authors: Fujimoto Haruo , Udagawas Masakazu , Obara Minoru , Fujiokas Tomoo
Published: July 2007

The HCl chemical laser is extremely useful because of its output wavelength 3.5‐4.0 μm (transparent window of the atmosphere) and its easiness in handling a gas. However, its output is smaller by one digit than the HF laser output. This paper proposes a use of a vibrationally excited H2 as a H donor of HCl and presents the computer simulation result using the equal‐gain model. It is found that the output can be increased considerably if H2 of 10‐2 (1%) is vibrationally excited to v = 1. The laser characteristics (output energy, power, pulse duration, etc.) are calculated under various operating conditions such as initial ignition (the initial H and Cl concentrations), the gas (H2/Cl2) ratio, etc.
Optical heterodyne detection of an airy signal field with a gaussian local‐oscillator field
Authors: Takenaka Takashi , Saga Nobuhiro , Fukumitsus Otozo
Published: July 2007

The heterodyne efficiency in the optical heterodyne detection of an Airy signal field with a Gaussian local–oscillator field is analyzed with consideration of the effect of wavefront of both fields. The analysis is made for the case where both fields are normally incident on the detection plane. The beam parameters of the local oscillator field which maximizes the heterodyne efficiency are derived for given signal field. When the detection plane radius Γ0 is very large, the effect of the wavefront becomes apparent as F increases for given less aperture and as the effective aperture decreases for given F. The effect of finiteness of the detection plane on the heterodyne efficiency is investigated numerically. The maximum heterodyne efficiency is obtained when Γ0 = 1.13Fλ. The deterioration of the heterodyne efficiency in cases of oblique and off‐axis incidences of the local oscillator field is examined numerically.
Memory mechanism in floating si‐gate tunnel injection mis structure
Authors: Hirose Masataka , Osakas Yukio , Yukitomo Kazuo
Published: July 2007

By analyzing the writing characteristics of the poly‐Si floating‐gate tunnel injection MIS as a nonvolatile memory device, the memory charge storage site and its density will become clear. A memory diode is fabricated in which the first oxide thickness ∼30Å, the undoped poly‐Si floating gate thickness ∼260Å and the second oxide thickness ∼260Å. Measurement of the flat‐band shift based on constant capacitance tracing method and measurement of the writing charge are conducted simultaneously. Results show that the writing charge centroid on the floating gate varies with the writing time. The memory charge storage sites are seen as the trap states in the poly‐Si so that the charge centroid shift is controlled by the charge‐discharge time constant of the traps. Also the trapping state density is estimated to be 8.3 × 1017 cm‐3.
30/20‐ghz band earth station for domestic satellite communication
Authors: Inoue Takeo , Kuramoto Minoru , Kato Haruhiko , Tanakas Kashio , Kaji Masatake
Published: July 2007

A design method, configuration and experimental results using a medium‐capacity communications satellite for experimental purpose (CS) for 30/20‐GHz band earth station are presented. The main features of earth stations are as follows. (1) The system will operate in the 30‐GHz band for up‐path and in the 20‐GHz band for down‐path to avoid interference from and to terrestrial microwave systems. (2) As a low‐noise amplifier for the 20‐GHz band, the helium gas‐cooled unit with noise temperature of 80 K and that of Peltier‐cooled unit with noise temperature of 220 K over the 2.5‐GHz bandwidth have recently been developed. (3) As a 30‐GHz band air‐cooled high‐power amplifier with the output power of 300 W, a traveling wave tube unit and a klystron tube unit both small in size, have recently been developed. (4) The earth stations were designed so as to reduce transmission loss between the antenna and transmitting or receiving RF (radio frequency) equipment.

The earth station has high performances. The effective radiation power (EIRP) is greater than 92 dBW and the receiving figure of merit (G/T) is 44 to 45 dB/K. Good transmission characteristics through the satellite link for TDMA with clock rates of 64 Mbps and FM‐TV communications were obtained. The earth station is of practical use.
Detection times and errors of returned optical pulses for satellite ranging
Authors: Suzaki Yasuzi , Tachibanas Atsushi
Published: July 2007

Due to the recent advancement of the peripheral technology, accuracy of satellite ranging by pulsed lasers is approaching the order of centimeters. However, to obtain such accuracy on the absolute distance btween the ground where the ranging equipment is located and the reference point on the satellite, more accurate evaluations are needed for corrections of various delays contained in the measured values and their errors. This paper discusses the detection time of the weak and distorted reflected wave from the satellite, the delay with respect to the reference point on the satellite, and the detection errors based on the threshold detection. As an example, we studied the case of a spherical satellite of radius 5 m loaded with many uniform reverse reflectors on the surface (corresponding to the ranging satellite GS‐1). It is shown that the error can be reduced to less than the minimum resolving power 0.4 ns (corresponding to 6 cm of the system if more than 15 receivable photons are obtained in the system made of a laser with a pulsewidth 200 ps.
A digital processing for modulation with a sampling rate conversion
Authors: Sue Hiroshi , Hoshiko Yukio
Published: July 2007

This paper describes a digital processing method for modulation which consists of sampling rate matching and digital filtering. Processing in a digital modulation system consists of spectrum shifting, filtering and orthogonalization of signals, etc.

Because of several sampling rates existing within a modulation system, matching of these sampling rates is vital. Depending on the variation of the sampling rate, the amplitude and higher harmonic distribution of the spectrum of the time‐sequence signal obtained by sampling vary. By utilizing higher harmonics produced by conversion for sampling rate matching, and filtering these harmonics by means of a digital filter, it is possible to shift the spectrum to any arbitrary frequency and orthogonalize the signals.

It is shown that a modulation system can be constructed without carrier multiplications. Further, modulation systems that can be processed by this method and processing methods for practical realization are illustrated.
Relations between types of t‐s‐t tdm switching networks and dynamic steps of path hunting
Authors: Saito Tadao , Ogino Nagao , Inoses Hiroshi
Published: July 2007

Most of the optimization methods for the design of switching networks aim at optimizing the efficiency of the switch, while paying very little attention to the complexity of the central procedure. It is possible to attain an extremely high switching efficiency in a PCM switching network at the expense of an increased number of steps in path hunting. Since the complexity and the number of steps in path hunting increase with the amount of traffic load, conventional method for the evaluation of path hunting procedures becomes inadequate. This paper describes and evaluates a relatively complex but efficient path hunting procedure. Using this procedure, high switching efficiency can be achieved without a significant increase in the number of hunting steps. Results of the evaluation of the path hunting procedure for some typical T‐S‐T types switching networks are presented.
Electromagnetic scattering by a conducting cylinder located near the conducting plane
Authors: Tabata Kenichi , Kozakis Shogo
Published: July 2007

Radar detection of an airplane flying near the ground is not possible. To solve this problem, we analyze electromagnetic wave scattering by a conducting cylinder located near the conducting plane. The backward and omnidirectional scattering patterns and field distributions (E and H wave) near the cylinder are derived for the plane wave incidence. A similar analysis is made for a cylindrical wave. The theory is confirmed by a model experiment using a linear current source at 9.6 GHz.
Experimental observation of invariant curves of mapping on forced oscillatory system described by Duffing's equation
Authors: Abe Minoru
Published: July 2007

The mapping method is applied to electrical circuits described by Duffing's nonlinear differential equation and the invariant curves are observed under various circuit parameters. The conventional circuit which is described by Duffing's equation consists of a series resonant circuit containing reactors. This circuit has difficulty in realizing nonlinear characteristics because nonlinear terms depend on the magnetization characteristics of the core. It is also difficult to evaluate accurately the attenuation constant of the equation because the eddy current loss and hysteresis loss of the core affect the circuit loss. From the viewpoint described above, this paper proposes a method of constructing nonlinear capacitors with any nonlinear characteristics using operational amplifiers, where the capacitor in the series resonant circuit has nonlinear characteristics. Using this experimental circuit and the invariant‐curve display device proposed previously by the authors, the invariant curves are observed experimentally. The existence of oscillation which correspond to double asymptotic solutions is confirmed.
Microprocessor implementation for bandwidth compression of continuous tone facsimile picture and a proposal of differential plane coding
Authors: Saito Tadao , Yanaka Kazuhisa , Inoses Hiroshi , Nakagawa Hiroshi , Sano Fumio
Published: July 2007

The research on applying the flexibility of a microprocessor into facsimile has been progressing. In general, it has been considered difficult to realize encoding and decoding processes by a general‐purpose one‐chip microprocessor due to the limitation of its processing capability. However, it is desirable to use flexible software processing for efficient encoding of a tone image or a mixed image between a tone image and characters. In this paper, we show a qualitative limit of an image decoding process by software using a one‐chip microprocessor based on experimental investigation. In addition, we propose differential Plane Coding which is an implementable coding system within this limitation. Especially, it has been proved that an efficient encoding of a mixed image is possible by changing the encoding system in the first differential plane depending on the nature of the image.
Threshold analysis and design of an FMFB demodulator through quasi‐linear approximation
Authors: Iwanami Yasunori , Nemoto Yoshiaki , Satos Risaburo
Published: July 2007

The FMFB (FM feedback) demodulator with the threshold extension capability is now very important in satellite communications.

Despite many works on the FMFB, practical design methods of the FMFB seem to have been greatly dependent on experimental results.

In this paper, the FMFB model in which both the open‐loop threshold and the feedback threshold are considered is introduced through the quasi‐linear approximation.

The theoretical design method is established using this model, and the design examples are given in the case of Enloe's loop filter to compare with Enloe's design method.
Automatic teg measuring and data processing system
Authors: Kotani Norihiko , Kawazu Satoru , Mitsuhashi Junichi , Yamano Tsuyoshi , Komoris Shinji
Published: July 2007

With the increase in integration and density of LSI, it has become necessary to control design and fabrication more precisely than before. In particular, for the precise control of the wafer process, a thorough analysis of element characteristics using test elements group (TEG) is essential. This paper describes a TEG measuring system which is capable of evaluating LSI composed of many elements. This system performs automatic measurements and data processing of wafers utilizing a minicomputer. Since the inputs required for the automatic measurement and data processing are performed in a conversational mode, it is possible to determine the next measuring condition of data processing method while the measured result is being analyzed. By these means, data collection and data processing of various TEGs at the development stage of the LSI can be carried out at a sufficiently satisfactory level. Moreover, by paying careful attention to the man‐machine interface it is possible for those people who are not used to a computer to perform the measurement and data processing easily. By realization of this system the various quantities and different kinds of measuring data required during the LSI development can easily be analyzed within 3 to 30 minutes. This results in a change of the development method of the LSI itself and enables us to perform precise control of the wafer process efficiently.
Analysis of the ferrite image waveguides using a mode matching method
Authors: Yamanaka Yutaka , Araki Kiyomichi , Naito Yoshiyuki
Published: July 2007

Ferrite is a non‐reciprocal material which is used in non‐reciprocal devices such as isolators or circulators for the microwave and optical bands. Waveguides containing ferrite, are usually analyzed by 2‐dimensional approximations but not by 3‐dimensional analysis. This paper utilizes a mode‐matching method to analyze ferrite image lines, and the analysis is compared with experiment. First, the mode‐matching method is applied to the mode analysis of a ferrite slab and we find its dispersion and field distribution. These modes are then used to analyze the image waveguide, especially its field patterns, which are quite different from those for the dielectric case; finally its validity is confirmed by experiment.
Microstrip line slot‐array antenna with reduced beam‐tilt
Authors: Nakaoka Kaijiro , Itoh Kiyohiko
Published: July 2007

Microstrip line slot‐array antennas consisting of slots placed on the ground plane on both sides of the microstrip line may be classified into resonant‐ and nonresonant‐types. Both types exhibit a beamtilt—namely, the main beam direction shifts as the operating frequency is changed away from the center frequency. This beam‐tilt causes the gain in the specified direction to degrade rapidly, which is a serious drawback in a system for receiving a signal with a given bandwidth from a fixed direction. To overcome this deficiency, a method available for waveguide slot‐array antennas is used and a design procedure is developed. Further, it is shown experimentally that beam‐tilt is almost nonexistent over a relatively broad frequency range and constant gain is obtained. The gain is higher than that of conventional antennas. Sidelobes are suppressed, especially for nonresonant arrays. The usefulness of the microstrip line slot‐array antenna with a reduced beam‐tilt is demonstrated.
Mnos memory degradation model and its lifetime
Authors: Mizusawa Takeshi
Published: July 2007

The large change in the characteristics of MNOS memory results from the variation of the trapping level charge in the interface of SiO2 and SiN with time. Thus, MNOS memory has the drawback of short life. It is difficult to understand the change in the aging characteristics by means of functional tests, but for digital LSI the operation‐limited supply voltage variation method can be used to characterize the variation of intrinsic device characteristics.

In this paper the above‐mentioned method is actually applied to the MNOS memory, and a capacitor charging and discharging model is proposed to quantify the aging‐caused changes. The agreement between the test results and the model, the activation energy for the changes, as well as the calculation method for the lifetime are presented.

It is shown that the MNOS device change can be estimated by the operation‐limited supply voltage test method, the magnitude of the change in the characteristics due to aging is modeled as an exponential function exp (‐t/τ) with respect to the time t and time constant τ, which can be shortened with an increase in temperature. Its activation energy is found to be 0.2 eV and the life is proportional to τ.
Interpolated Z‐transform of the S‐parameter in the transient analysis of electrical networks
Authors: Kato Masami
Published: July 2007

Earlier, 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

This 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

Many 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

Operation 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

The 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

The 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

A 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

The 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.