bluuebunny/crossref_metadata_2025_split huggingface dataset:
Picture quality of different pixel arrangements for large‐sized matrix displays
Authors: Hara Zen‐Ichiro , Terazaki Nobuo , Shiramatsu Naoki , Iwata Shuji 
Published: July 2007

AbstractThe image information theory is introduced to the study of pixel arrangement for flat displays which has been based mainly on subjective evaluation tests. the objective is to make a theoretical elucidation of the relations between different pixel arrangements‐particularly pixel arrangements of light‐emissive elements for large‐sized matrix displays‐and picture quality.First, the factors determining picture quality are identified using a picture model incorporating the sampling of the original picture. As a result, the Nyquist limits are shown to be essential.Second, the Nyquist limits of different pixel arrangements are evaluated. the areas surrounded by the Nyquist limits are shown to consist of colored and discolored regions. This observation is used to relate the Nyquist limits to visual limits and picture quality.Third, the picture quality of typical pixel arrangements for large‐sized matrix displays is examined. the quality of still and motion pictures displayed by the RGB‐trio and RGGB‐mosaic arrangements are compared by means of subjective evaluation tests and three‐dimensional spectrum analysis. the comparative analysis gives the following conclusions:
In displaying still pictures, the RGGB‐mosaic arrangement has the effective number of pixels about twice the real number of pixels because of the overlaps of adjacent pixels, but the RGB‐trio does not have this effect.
In displaying motion pictures, the RGGB‐mosaic arrangement provides better picture quality than in the case of still pictures but the RGB‐trio arrangement does not.
Diffraction of electromagnetic waves from a line source by a conducting strip
Authors: Kinoshita Teruhiro 
Published: July 2007

AbstractThis paper considers the problem of scattering of electromagnetic waves by a strip conductor when the source is a line current source or a line magnetic current source. the problem is analyzed as a two‐dimensional boundary value problem when the strip conductor thickness is negligibly thin and the distance from the center of the strip to the source is larger than one‐half its width. the expansion functions of the current are selected to satisfy the edge condition. By means of the spectral domain method, the simultaneous equations for the expansion coefficients and the specific expressions for the coefficients are derived. the current distributions and the scattered far field are computed numerically. In the analysis process, it is shown that the coefficients derived are identical to those of the simultaneous equations in the analysis for the plane wave incidence making use of the Weber‐Schafheitlin discontinuous integral.
Optical imaging characteristics of direct‐contact type linear‐image sensor
Authors: Nagata Tatsuya , Shimizu Hiroya , Watanabe Michihiro 
Published: July 2007

AbstractAn analysis program is developed to evaluate the readout ability of the direct‐contact type linear‐image sensors that do not possess the image‐forming optical systems. It is used exclusively to evaluate the readout characteristics of the direct‐contact type linear‐image sensors. the program deals with the sensors with multi‐layer structures parallel to the XY plane of the 3‐D (and mutually orthogonal) XYZ coordinate system. the optical path of the illuminating light emerging from the source, attenuations at the boundaries between different materials and the lights blocked by the electrode and the receiver are calculated if they are used in determination of the illumination distribution in the XY plane. the calculation procedure comprises two parts: the illumination on the document plane due to emerged light from the source, and the reflected light from the document onto the sensor. This program takes not only document plane reflections into account but can also factor in the reflections caused by light penetrations into the document paper (Yule‐Nielsen effect). Investigations using this program show that the resolution of the read‐out function of direct‐contact type sensors strongly depends on the distance from the document to the receiver and the quality of its paper.
Frequency divider based on miller integral‐type SC astable multivibrator
Authors: Sasaki Hirofumi , Yahara Mitsutoshi , Kawahara Keiji , Zhu Hong‐Bing , Ueno Fumio 
Published: July 2007

AbstractIn a conventional‐type astable multivibrator, the upper limit of the division ratio for stable dividing operations is at most 1/20. In this paper, we propose and analyze a frequency divider based on the Miller integral‐type switched capacitor (SC) astable multivibrator that maintains stable operation even with a large dividing ratio.This divider has a circuit configuration in which the state reversal occurs at a point during the straight fall of the output voltage waveform of the Miller integrator in a stepwise fashion. Therefore, the divider is not affected by either supply voltage or external noise. the dividing ratio can be varied in a much larger range than that of the conventional type simply by changing the value of the capacitor. the mathematical formula can be expressed simply with only circuit parameters. the computed values and the measured values agree well.Also, since no trigger generator is needed (as is the case with a conventional type), the dividers can be cascaded easily. the resultant dividing ratio is the product of the individual dividing ratios. Further, by using two sets of modifications of this divider and by using one of them as the feedback circuit, a pulse number converter can be realized in which the ratio of the input pulse number and the output pulse number can be varied arbitrarily.
Performance of partial response system in perpendicular magnetic recording
Authors: Osawa Hisashi , Okamoto Yoshihiro , Kurihara Yoshitake , Nishida Yasutaka , Muraoka Hiroaki , Nakamura Yoshihisa 
Published: July 2007

AbstractThe error‐rate performance of the partial response maximum likelihood (PRML) system combining the partial response (PR) system with the Viterbi decoding, which is a type of maximum likelihood (ML) decoding, is investigated in perpendicular magnetic recording using a multilayered main‐pole head. Waveform approximation is carried out with regard to the isolated reproducing waveform obtained by experiment; and, based on this, the bit error rate is determined by computer simulation.First, taking into account the noise increase due to equalization, the signal‐to‐noise ratio (SNR) at the discrimination point and the bit error rates of bit‐by‐bit decoding of several PR systems using the characteristics of the multilayered main‐pole head are determined. Next, the bit error rates of the PRML system are determined for these PR systems and then compared with those for the conventional PR system. Then it is clarified that the best performance is obtained by the PR(1, 0, 0, 0, ‐1) system among these PR systems, and the improvement of SNR compared with the conventional PR system is about 1.9 dB in the case of the bit‐by‐bit decoding system and 4.1 dB in the case of the PRML system at an error rate of 10−4.
Analysis of radiation characteristics of a polyhedron‐approximate reflector antenna using the aperture integration method and the current distribution method
Authors: Hanayama Eiji , Takano Tadashi 
Published: July 2007

AbstractIn this paper, the radiation characteristics and its analysis method are discussed for a polyhedron‐approximated reflector antenna in which the reflector is made of several planar facets as in a large deployable antenna. Based on the current distribution method considering the law of reflection and the effect of diffraction, the aperture integration method using the ray tracing containing an approximation in the law of reflection is used for the electric field distribution of a polyhedron‐approximated antenna. It is found that the electric field of the present antenna becomes maximal at the joint between the facets. It is shown that the far‐field characteristics of the antenna derived by the aperture integration method based on the approximate ray tracing and by the current distribution method are identical. the relationship was found between the equivalent aperture plane where the field distributions derived by the two methods are identical. Further, by means of the rigorous ray tracing method, the three dimensional ray behavior is shown. It is found that the aperture integration method based on the rigorous ray tracing method is inappropriate for the calculation of the radiation characteristics of the present antenna.
Equivalent impedance of building columnc and girders against lightning surges
Authors: Sato Masaji , Kuramoto Shoichi 
Published: July 2007

AbstractIf a telephone center building is subject to a direct hit by lightning, lightning surge currents flow in the columns, girders, and walls and, hence, the equipment may be damaged or may malfunction due to induction into the communication cables and power lines. Studies on the current and voltage distributions in the building by the direct lightning hit have been carried out. One of the fundamental subjects is the method of estimating the equivalent impedance of actual columns and girders. There has been no sufficient understanding because the dimensions of the steel frames are large and the shapes are extremely complex.In this paper, scaled‐down models of the columns and girders are constructed first and the impedance measurement method for these models is discussed. It is found that the current distributions in the model become almost homogeneous if several return wires are placed around the scaled model of the column so that a measurement close to an actual situation can be carried out.Next, by means of this measurement method, a simple cylindrical conductor rod and the scale model of the column are compared. Hence, it is proven experimentally that the resistance and the inductance of the columns and the girders can be estimated from the computational equation for the cylindrical conductor rod with identical surface area to those of the steel frame and the steel rod, even if the shapes are complex.Finally, the actual columns of a reinforced concrete building are measured and agreement is confirmed between the estimate from the scale model and the actually measured values.
Analytical solutions of the scattering properties of h‐plane junctions in rectangular waveguides
Authors: Widarta Anton , Kuwano Shuzo , Kokubun Kinchi 
Published: July 2007

AbstractThe scattering properties of the H‐plane waveguide discontinuities such as the cross junction, T‐junction, and right‐angle bend are analyzed taking their symmetry into account. the solutions are synthesized in two new and simple expressions. These solutions are treated rigorously by the mode‐matching method in which each junction section is divided by a circular region and the electro magnetic fields are matched with the scattered waves into waveguide regions at the boundaries. By means of the accurate numerical results obtained in a wide frequency range, the scattering properties of the H‐plane junctions in a standard waveguide and an oversized waveguide are examined in detail. the latter is believed to be useful for an approximnte estimation of the scattering properties of crossing roads in underground shopping centers.
LiNbO3 optical waveguide modulator for bidirectional transmission
Authors: Ishikawa Tadasu , Furuta Hiroyuki 
Published: July 2007

AbstractA new bidirectional external optical modulator using Fresnel reflection light has been proposed and developed. Since weak light reflected from the end of a crystal can be modulated in this modulator, no laser source is required if the modulator is intended for home use. This modulator also has no significant effect on a video signal in the downstream. In the external modulator designed for trial use, insertion loss was less than 3 dB, the half‐wave voltage was 10 V, and the half‐wave voltage difference and phase difference between the two modes were 2 percent and 5 degrees. A small module of the present device was created for use in a home optical terminal station of a demand access‐type Hivision CATV system. In this bidirectional transmission experiment, stable channel selection and good Hivision receiving image with C/N > 20 dB were confirmed. For the uplink 64 kbit/s NRZ signal, bit error rate (BER) of less than 10−8 was obtained.
Precise formula for calculating spot size in optical waveguides and its accuracy
Authors: Kokubun Yasuo , Tamura Shuichi 
Published: July 2007

AbstractSpot size is a fundamental parameter that expresses the degree of spreading of the transverse electric field distribution of a guided mode. This quantity is used when there is offset loss between different guided wave elements. It is extremely important to determine an accurate spot size value in the design of an optical integrated circuit containing a number of guided wave devices. the goal to derive a highly precise spot size requires a least square approximation of a transverse electric field distribution of the guided wave in terms of the electric field of a Gaussian beam.The transverse electric field distribution of the fundamental mode propagating in an optical waveguide was expanded orthogonally in terms of Hermite‐Gaussian functions. With a 0th‐order expansion coefficient as the maximum, an approximate equation suitable for highly accurate numerical computation was derived. the present equation does not change its equation form by Fourier transform and has mathematical validity. Fur ther, when the approximate equation is used in the present study, the junction loss of the offset axes of the waveguides can be approximated best by that of the Gaussian beam waves.This paper uses as an example the TE mode in a three‐layered slab waveguide in studies of approximation accuracy for the defined spot size value. With the present approximate equation, the spot size can be derived accurately by a successive approximation. It was demonstrated with an actual successive approximation that accuracy improves significantly and is better than the one obtained from a conventional equation.
Quantum energy control of multiple‐quantum‐well structures by selective area mocvd and its application to photonic integrated devices
Authors: Aoki Masahiro , Suzuki Makoto , Sano Hirohisa , Taniwatari Tsuyoshi , Tsutsui Takayuki , Kawano Toshihiro 
Published: July 2007

AbstractQuantum energy control is proposed in the form of a multiple‐quantum‐well (MQW) structure fabricated by selective metal organic chemical vapor deposition (MOCVD) growth to obtain high‐performance multiple‐function semiconductor photonic integrated devices. Its fundamental principle and the applied photonic integrated device are discussed. In general, semiconductor photonic integrated devices require semiconductor layers with different bandgap‐energy states for each structural device having a different function formed on the same semiconductor substrate.In this paper, the position‐dependent growth speed and the growth‐layer compositions on the substrate are controlled by selective MOCVD growth so that the quantum energy levels of the InGaAs/InP MQW structures grown simultaneously are varied over the substrate surface. As a result, a controllable range of the quantum energy level spanning over 200 meV and a high‐quality crystal configuration of selectively grown layers comparable to that formed by conventional growth processes have been confirmed.Application of this new integration method required that we design a monolithic integrated device of a distributed feedback laser diode and an electric field absorption‐type modulator, as well as a multiple‐wavelength distributed feedback laser array. Despite the simple design method, good crystal quality of the selectively grown layers, good optical coupling between the devices, and good device performance were observed.
Surface operating optoelectronic devices and applications to optical parallel processing
Authors: Hara Kunihiko , Ohta Jun , Nitta Yoshikazu , Kyuma Kazuo 
Published: July 2007

AbstractSince, in surface operating semiconductor optoelectronic devices, signal reception and transmission are carried out in the direction perpendicular to the device surface, numerous parallel processes can be achieved using two‐dimensional arrays of these devices.To realize image processing systems, massively parallel computing systems and high‐speed/high‐capacity communication systems, there has been considerable research on surface operating optoelectronic devices.This paper describes the operating principles and present status of typical surface operating optoelectronic devices and discusses the electrical and optical connections in a three‐dimensional (3‐D) parallel optoelectronic system using two‐dimensional operating optoelectronic device arrays. Finally, applications to optical switching networks, direct image processes and optical neural networks will be introduced.
Hybrid optical integration technology
Authors: Kobayashi Morio , Kato Kuniharu 
Published: July 2007

AbstractThe combination of hybrid integration technology with guided‐wave optical technology is expected to provide more functional optical devices with high performance, compactness, and high productivity.This paper reviews recent developments in the hybrid integration of optical and electronic components with a silica‐based planar lightwave circuit on silicon. First, edge‐hybrid, surface‐hybrid, and film‐hybrid integration technologies are described. Next, basic technical issues concerning optical component integration, electronic component integration, and packaging are discussed. Emphasis is placed on optical alignment, component fixing, mode‐field matching, and antireflection techniques in the optical component integration. Finally, examples of fabricated hybrid‐integrated optical devices are presented.
Improvement of reconstructed images with binary digital phase holograms using error diffusion methods
Authors: Tanaka Ken‐Ichi , Shimomura Teruo 
Published: July 2007

AbstractSome error diffusion methods have been reported which are applied to amplitude quantize holograms, kinoforms, and trinary digital phase holograms. However, there is no method which is applied to binary digital phase holograms.This paper discusses improving reconstructed images with binary digital holograms using error diffusion methods in computer simulation. Consequently, it is clarified that error diffusion methods are effective, in general, in the range of reconstructed images not in contact with the diffused noise and the maximum ratio of an input domain is approximately 1:8.In the range of reconstructed image that does not contact with diffused noise, the error diffusion method gives a superior reconstructed image compared with any other encoding methods. Further, reconstructed images by computer simulation are verified and the deterioration factor in optical systems using optical experiments is eliminated.
Planar lightwave circuits based on silica waveguides on silicon
Authors: Suzuki Senichi , Kawachi Masao 
Published: July 2007

AbstractOptical communication systems are expanding from the conventional point‐to‐point system to the mesh‐type network systems for subscribers. As a result, the requirement for passive circuits such as optical divider, optical combiner, and optical switch is increased. Since optical waveguide‐type circuits have superior stability and mass producibility, they are considered important for construction of future optical communication systems.This paper describes development of the planar lightwave circuit (PLC) technology using the silica‐based waveguide on a silicon substrate. In the first half, the design technology of the silica‐based waveguide, the design and production examples of PLCs, and the system experiment examples are introduced. In the latter half, the latest tendency of high‐density integrated PLCs is emphasized based on the use of the high relative refractive index difference (high‐Δ) with a view to large‐scale PLC, and the characteristics of the high‐Δ waveguide and examples of its applications to high‐density integrated optical circuits are presented.
Er‐doped silica‐based planar ring resonator
Authors: Hattori Kuninori , Kitagawa Takeshi , Oguma Manabu , Hibino Yoshinori , Ohmori Yasuji , Horiguchi Masaharu 
Published: July 2007

AbstractA new configuration of a ring resonator is proposed by using an Er‐doped silica‐based waveguide. Its laser oscillation and variable finesse were realized. to determine the Er concentration suitable for the Er‐doped waveguide ring resonator, the Er concentration dependence of the threshold pump power for laser oscillation in an Er‐doped waveguide ring resonator is analyzed numerically. It was found that an optimum Er concentration is in the range of 0.3 fc 0.5 wt.%. Further, from the actual measurement, it is confirmed that the gain of the silica‐based waveguide with Er doping concentration in this range is larger than the loss of the ring resonator. Then, an optimum coupling condition of the directional coupler is studied. It is found that a maximum value of 91 percent is obtained as the coupling ratio at a wavelength of 1.533 μm for a coupling length of 1.0 mm. Based on these investigations, an Er‐doped waveguide ring resonator with a circumferential length of 9.2 cm is fabricated. As a result, an Er‐doped waveguide ring laser is realized that has an oscillation center wavelength of 1.533 μm, a threshold value of 93 mW for the pump power and a slope efficiency of 0.3 percent. the oscillation modes of the realized ring laser are longitudinal multimodes with its free spectral range (FSR) of 2.2 GHz. the narrow line characteristics of an average line width of 200 kHz are found. From the results of the transmission spectral measurement, it is confirmed that the Er‐doped waveguide ring resonator works as a stopband‐type optical frequency filter. In addition, it is found that the finesse can be varied by controlling the pump power. Maximum finesse is 36.
Frequency dispersion and modulated signal distortion characteristics of gaas power MESFETs at large signal operation
Authors: Miyatsuji Kazuo , Furukawa Hidetoshi , Ueda Daisuke 
Published: July 2007

AbstractIn the search for a cause of modulated signal distortion of a GaAs power FET, an analysis is made for the frequency dispersion caused by the surface trap. First, the frequency dispersion characteristics of the Vgs‐Id relationship of the FET under a large signal operation are measured. It is found that the Vgs‐Id characteristics at high frequencies are very different from the one at dc. It is found that the drain current decreases near Vgs = 0 V. Further, simulation is carried out for the intermodulation distortion using the Vgs‐Id characteristics at the high‐frequency region. It is found that an increase in the nonlinearity of the Vgs‐Id characteristic due to frequency dispersion is the cause of increased modulated signal distortion. From the measured temperature dependence of the frequency dispersion of the drain current, energy levels related to the dispersion are found to be 0.56 and 0.19 eV. Further, a comparison is made between SiN and SiO2 surface passivation films. It is found that frequency dispersion is small and a low distortion characteristic can be obtained with the SiN film.