bluuebunny/crossref_metadata_2025_split huggingface dataset:
A high‐speed high‐density array‐multiplier‐accumulator for digital signal processing
Authors: Minami Toshihiro , Kasai Ryota , Matsuda Hiroaki , Kusaba Ritsu 
Published: July 2007

AbstractThis paper discusses the downsizing and speed improvement of short‐word multiplier‐accumulators, which are frequently used in digital signal processors. As a first step, the optimal configuration for an array‐type carry‐save adder is considered where the shortest path in the full‐adder is used to propagate the sum signal and the carry signal is sent to the full‐adder of the two lower stages by skipping a stage. A configuration of the full‐adder suitable for the structure is proposed. The case of eight partial product additions shows that the delay can be reduced by 22 percent compared to a simple array‐type carry‐save adder. Then the short‐word carry look‐ahead adder using the pass‐transistor logic is considered. It is shown that a single‐stage carry look‐ahead circuit with a four‐bitwise iterative structure exhibits nearly the same delay as a two‐stage carry look‐ahead circuit. In other words, the former is better suited to downsizing. This paper intends to examine the effectiveness of the foregoing new array‐type carry‐save adder and the single‐stage carry look‐ahead circuit using the 0.5‐μm CMOS technology. A 16‐bit X 14‐bit + 31‐bit multiplier‐accumulator has been designed and is evaluated for cases where the array‐type carry‐save adder is used to handle accumulation as well as partial products. The resulting area and delay are 0.77 × 0.78 mm2 and 6.8 ns, respectively. The effectiveness of the approach used in this paper is evaluated by constructing a multiplier‐accumulator, but the method is also useful in constructing a multiplier.
A time A‐D converter LSI for accurate measurement of multitime‐interval by digital processing
Authors: Watanabe Takamoto , Ohtsuka Yoshinori , Akita Shigeyuki , Hattori Tadashi , Agatsuma Syuuji , Isomura Hirofumi 
Published: July 2007

AbstractThe authors previously have reported on the “ring gate delay” system which digitizes the infinitesimal time interval with the delay time of the inverter as the resolution, without using the high‐speed reference clock [1]. A problem then is the improvement of the accuracy since the delay time of the inverter depends on various conditions such as the ambient temperature, the supply voltage, and the fabrication condition. To remedy this point, an LSI is constructed and the delay time of the original circuit is monitored continuously using the quartz oscillation clock of a relatively low frequency as the reference, and the time to be measured is digitized with a high accuracy based on the delay time. In this system, it is not necessary to control the delay time, which makes it possible to utilize the shortest delay time.By a single measurement process using a single input port, up to four pulses can be measured consecutively. If the pulse interval to be measured in less than the specified time, the pulses are combined into a single pulse and an incorrect operation is prevented.In this study, a sample device is constructed by a 1.5‐μm CMOS process. The measurement range of 2200 ns (12 bit) with the time resolution 0.5 ns is achieved using the supply voltage of 5 V. The minimum pulse interval that can be measured is 55 ns (at 25°C). The reference clock used is 2 MHz. The number of transistors is 15, 000 and the chip size is 3.5 mm × 3.8 mm. The constructed LSI is composed totally of digital circuits. The operation is robust against the environmental condition, and a stable operation is realized for the ambient temperature of −35 to 140°C.
Low‐profile filter using open disk dual‐mode dielectric resonators
Authors: Ishikawa Youhei , Hidaka Seiji , Ise Tomoyuki , Matsui Norifumi 
Published: July 2007

AbstractIn this paper, a low‐profile filter using an open circular dual‐mode dielectric resonator is proposed as a filter for a mobile communication base station. The basic configuration of the dielectric resonator consists of two dielectric disks with electrodes on both sides stacked in the axial direction; they are installed in a shielded cavity. The doubly degenerate fundamental mode has an electric field parallel to the axial direction of the dielectric disks, and the resonator can be made low profile without significantly changing the resonant frequency. The equivalent circuit of the dual‐mode resonator is given in terms of a ring‐shaped transmission line with its electric length of 2°. The equivalent circuit of the multistage filter using this resonant circuit can be designed by the Chebyshev filter design method. A six‐stage filter with the center frequency of 985 MHz and the passband width of 10 MHz was fabricated. The results agreed well with those of the simulation. The insertion loss at the center frequency is 1.3 dB, and the external dimensions are 158 × 54 × 23.5 mm.
Bleustein‐Gulyaev‐Shimizu wave resonators formed on ceramic substrates and their applications
Authors: Morozumi Kazuhiko , Kadota Michio 
Published: July 2007

AbstractIn a frequency range that is between 30 and 60 MHz, piezoelectric resonators have not been employed widely in consumer electronics due to their size and the difficulty in precisely tuning their frequencies. Thus, liquid crystal (LC) resonators have been extensively used instead.The authors of this paper have successfully developed and commercialized Bleustein‐Gulyaev‐Shimizu wave free‐edge reflection resonators made of piezoelectric ceramics lead zirconate‐titanate (PZT), which have both a small temperature coefficient (9 ppm/°C) and a large electromechanical coupling coefficient (k2 = 0.22).These resonators have been evaluated as additional traps for nonfrequency tuning resonators that replace both LC resonators requiring tuning and resonators needing autofrequency tuning (AFT). In the former application, the present resonators exhibit trap characteristics with steeper and larger attenuation than those of conventional LC resonators. In the latter application, the present resonators exhibited AFT sensitivity characteristics which are similar to those of conventional LC resonators. When the present resonators were incorporated into voltage‐controlled oscillator circuits, they exhibited a very wide adjustable frequency range of 3.7 MHz.
Spontaneous emission behavior and its injection level dependence in three‐dimensional microcavity surface emitting lasers
Authors: Hamano Tetsuko , Iga Kenichi , Baba Toshihiko 
Published: July 2007

AbstractVertical‐cavity surface emitting lasers (VCSELs) are expected to be used as light sources in two‐dimensional array optoelectronics because of their structure and probable characteristics. The control of spontaneous emission by wavelength‐size microcavities is effective in lowering the threshold of surface emitting lasers. The control of spontaneous emission using the spontaneous‐emission factor of three‐dimensional microcavities was presented by the authors in previously done work. This paper reports on further progress in the analysis of the spontaneous‐emission factor. The standing wave distribution inside a planar or three‐dimensional microcavity is first investigated. Increase in the spontaneous‐emission factor and control of the optical mode taken out of the microcavity are estimated under the increased optical confinement factor due to varied external boundary conditions of the distributed Bragg reflector (DBR). The variations of the spontaneous emission and output characteristics associated with injection level are discussed. It is shown that the spontaneous‐emission factor varies with cavity resonant wavelength and the injection level affects the output optical characteristics.
A coding and decoding method of track address with viterbi decoding
Authors: Hayashi Nobuhiro 
Published: July 2007

AbstractAs the recording method for the track address in the magnetic disk drive, the Gray code with redundancy (Gray‐like code) has been used so that nearly the correct value can be obtained even if the head is located close to the track boundary. This paper proposes a recording/reproducing method for the track address in the magnetic recording where the Viterbi decoding is applied to the Gray code record. The detection performance is evaluated by the theoretical analysis and the simulation. As a result, it is seen that the same or better performance compared to the conventional method can be obtained. By the proposed method, the area for the track address recording can be reduced to one‐half to two‐thirds the conventional method. This helps to increase the recording capacity and improve the maximum seek time.
An ultrabroadband monolithic lossy match power amplifier using prematching circuits
Authors: Itoh Yasushi , Mochizuki Mitsuru , Nii Masatoshi , Kohno Yasutaka , Takagi Tadashi 
Published: July 2007

AbstractThis paper describes the design, fabrication, and performance of wideband monolithic lossy match power amplifiers employing prematching circuits, which make the frequency‐dependence of input and output impedance of FETs small. First, it is shown theoretically that a wide bandwidth can be achieved by using prematching circuits in the design of lossy match power amplifiers. Second, a novel constant‐resistance network and a parallel resonant circuit are proposed as prematching circuits. Impedance matching methods using prematching circuits are also described. Finally, by employing these prematching circuits in the design and fabrication of a C∼K band‐power amplifier, it is experimentally shown that the impedance matching methods using prematching circuits are useful in the design of wideband lossy match power amplifiers. The amplifier exhibits a linear gain of 10 ± 2.3 dB, a saturated power of 28.3 ± 1 dBm, and a drain efficiency of 12.6 ± 2.2 percent over 5∼21 GHz. These measured performances are in good agreement with the calculated results. The prematching circuits, which make the frequency‐dependence of input and output impedance of FETs small, are useful for achieving a wide bandwidth of lossy match power amplifiers. In addition, the parallel resonant circuit, which comprises only reactive elements, is also useful in the design of output matching circuits for achieving high gain and high power.
Design of dielectric multilayer bandpass filters using fundamental thickness of layers
Authors: Wakabayashi Isamu , Miyauchi Kazuhiro 
Published: July 2007

AbstractThe general design principle of the dielectric multilayer bandpass filters proposed by the authors is applied to the case where only the fundamental thickness of dielectric layers are used. The actual design procedure, layer structure, necessary formulation in the design, conditions, and design examples are presented. Further, with respect to various combinations of the parameters, 900 filters are designed and their characteristics are verified to show the distribution of their design errors.In actual designs, the objectives are third‐, fifth‐, and seventh‐order Butterworth and Chebyshev filters (0.5‐dB and 1‐dB ripples) using SiO2 and TiO2 and the center wavelength of 1.3 μm. The percentage bandwidths are taken to be up to 10 percent with angles of incidence up to 30 deg with P or S polarizations.It is understood that, when the bandwidth is set to be less than 5 percent or when it is set in the range of 5 to 10 percent, it is possible to achieve designed filters with percentage bandwidth errors below 1 percent and 3 percent, respectively. In all Butterworth filters, the insertion loss at the center wavelength was below 0.04 dB. For the objective ripple in Chebyshev filters set at 0.5 dB, the maximum ripples of all filters distribute within 0.15 to 2 dB while, in the case of 1‐dB objective ripple, they are in the range from 0.4 to 2.3 dB.
The analysis of polarization‐insensitive characteristics for semiconductor optical amplifiers with tensile strained multiple quantum wells
Authors: Takaya Hironobu , Kambayashi Toshio 
Published: July 2007

AbstractIn this paper, the aims of our study are to analyze the gain of semiconductor optical amplifiers with tensile strained multiple quantum wells and to examine the structure for polarization‐insensitive characteristics for the purpose of showing the design guidelines. Since lasers with conventional lattice‐matched multiple quantum wells have large optical confinement coefficient and large gain coefficient for TE mode, they are not polarization insensitive. Since the modal gain is the product of the optical confinement coefficient and the gain coefficient, the elimination of polarization sensitivity requires increasing the gain coefficient for the TM mode by applying the tensile strain to the well layer in order to compensate for the difference in the optical confinement factor. Assuming a multiple quantum well structure, the analysis obtains the strain distribution over the structure and an envelope function of the wave function and calculates the gain using a density matrix method by electron relaxation effect. It includes the band mixing effect of valence bands. As a result, a structure with little modal gain difference over a wide range at 1.55‐μm wavelength has been designed. Also, as a result of examining the effect of deviation from the designed values, it has been found that the variation in the material composition (amount of strain) has a larger effect on the modal gain difference than the variation in the quantum well thickness.
High‐frequency analysis of radiation field excited by incident whispering‐gallery mode over concave‐to‐convex boundary
Authors: Goto Keiji , Ishihara Toyohiko 
Published: July 2007

AbstractAn asymptotic method of analysis is studied for the radiation field when the lowest‐order whispering gallery (WG) modes propagating from the concave side of the concave‐to‐convex boundary with a variable radius of curvature are radiated into the free‐space on the convex side. The modal ray congruences of the WG mode are radiated into the free space after being converted to geometrical rays. Both the caustics and the shadow boundaries are created in the space. As the expression of the radiated field near the caustic, the modal rays incident into the concave part are used for deriving the physical optics integral.By applying the high‐frequency asymptotic analysis in the case of two saddle points closely spaced to the evaluation of the integral, the uniform asymptotic solution was derived. Also, as the radiating field on the sufficiently shadow side of the caustic, the complex ray solution was derived. On the other hand, as the radiating field in the transition region near the shadow boundary caused by the convex region, an asymptotic solution was derived in the form of an extension of the conventional UTD (Uniform GTD) to the case where the geometrical ray converted from the modal ray is incident to the boundary. The numerical results obtained by various asymptotic expressions are compared with the reference solution and the geometrical optics figure drawn by the modal ray tracing. The effectiveness of the asymptotic solution and the propagation and radiation phenomena of the WG mode were derived.
Vibration mode analysis of piezoelectric‐ceramic cylinder vibratory gyroscopes with interdigital electrodes
Authors: Abe Hiroshi , Yoshida Tetsuo , Nakamura Kiyoshi 
Published: July 2007

AbstractUsing the deviation of vibration mode axes from their ideal positions, an equivalent circuit is introduced for bending mode‐based cylindrical piezoelectric ceramic vibratory gyroscopes which have interdigital electrodes for both driving and detection. By comparing experimentally determined impedance characteristics with numerically simulated impedance characteristics, it is possible to estimate shifts in a vibration mode axis of a resonator. Furthermore, it is possible to design a high‐performance vibratory gyroscope that produces no output voltage even when it is not subjected to an angular velocity by degenerating two vibratory modes. This degeneracy can be induced by laser machining a groove at the high‐frequency vibration mode axis.
Effects of deposition rate control process on the adhesion of evaporated aluminum films
Authors: Kobayashi Fumitoshi , Nomura Akio , Kano Tetsuo 
Published: July 2007

AbstractEffects of the deposition rate control process were investigated by measuring adhesion strengths of Al films using the scratch test method. The Al films tested were deposited on glass substrates. The results indicate that the adhesion strength depends strongly on the deposition rate and increased by a factor of three when the deposition rate was increased from 1 nm/s to 10 nm/s. When the deposition rate was accelerated at a constant acceleration rate of 0.01 to 0.05 nm/s2, the adhesion strength was constant regardless of the acceleration rate and the final deposition rate used. Effects of the two‐stage evaporation process also were investigated. In the two‐stage evaporation process, the initial deposition rate was set at a constant value of 1 nm/s. Subsequent deposition rates used were 3 nm/s, 6 nm/s, and 9 nm/s. The thickness ratio of the initially evaporated films to subsequently evaporated films was varied. The results indicate that the adhesion strength decreased with increasing thickness of the initial film. However, when the thickness of the initial film reached 50 nm, the adhesion strength was no longer affected by the subsequent films. Microstructural analyses of the evaporation film indicate that the films with higher adhesion strength had larger particle size.
orientation measurement of Al(111) planes in Al‐Si‐Cu interconnection layers by the image‐plating glancing‐angle x‐ray diffraction method
Authors: Kitamura Taira , Hara Tohru , Okuda Tomohisa , Shinada Kiyotaka , Kino Yosihiro 
Published: July 2007

AbstractThe orientation of Al(111) planes in Al‐Si‐Cu interconnection layers is determined precisely by the image‐plating glancing‐angle X‐ray diffraction measurement technique. Contrary to the results obtained by the conventional X‐ray diffraction method, the Al(111) planes are tilted randomly at axial angles between 0° and 16°. A 50‐nm thick layer has a large number of nuclei which were rich in Cu and has an average grain size of 0.12 μm. Furthermore, the Al(111) planes are oriented parallel to the substrate surface. However, the grain size increased with increasing film thickness and reaches a grain size of 1.10 μm. In addition, the Al(111) planes are determined to be tilted at random.
Blue‐light emitting vacuum fluorescent display using Te‐doped ZnS phosphors
Authors: Araki Hiroyuki , Kanie Hisashi , Nagano Mashiro , Sano Masatoshi , Yonezawa Yoshihisa 
Published: July 2007

AbstractZinc sulfide (ZnS), which is one of the wide‐gap II‐VI compound semiconductors, has been used as the blue phosphor for vacuum fluorescent displays (VFD). Because the ZnS phosphor has a high resistivity, it is usually mixed with a conductive powder such as In2O3. ZnS crystals grown from Sb2Te3 solutions showed a blue emission at room temperature due to the Te impurities (the isoelectronic centers of the Te‐Te pair) and had relatively low resistivities (about 105 Qcm), due to the presence of Sb impurities. The VFDs prepared directly from these crystals as phosphors without use of conductive powder were investigated. The VFDs emitted light at an anode voltage higher than 15 V. The luminance increased linearly with the anode voltage. For VFDs employing crystals with 0.2 at.% Te, the luminance was 530 cd/m2 and the luminous efficiency was 0.30 lm/W at an anode voltage of 60 V. The emission had a peak at 460 nm and a chromaticity coordinate of (0.15, 0.15) that was independent of the anode voltage. The luminance decreased with increasing temperature and at 80°C was 3 percent of that at 25°C. The luminance and the luminous efficiency improved with increasing Te concentration in the phosphor crystal.
Analysis of electrical characteristics of anodic foils with tunnel pits for electrolytic capacitors
Authors: Nakamura Jin , Maeda Takao 
Published: July 2007

AbstractIn the electrolytic capacitor, the tunnel pits of the anodic foil provide most of the overall capacitance and it is important from the viewpoint of analyzing the essential characteristics of the capacitor to investigate the mechanism inside the tunnel pits. The purpose of this paper is to promote such an understanding and to present a new analysis of the principle and the actual situation of the tunnel pits. First, the internal state of the pit in the normal operation is assumed. Then, a new parallel distributed C‐R equivalent circuit is presented based on the path resistance concept related to the existence probability of the movable charge. By analyzing the characteristics of the equivalent circuit, the characteristics inside the pit can be estimated.It is shown that the path branch (1) of the charge moving between the infinitesimal oxide layer adjacent to the deepest part of the pit and the pit entrance has tan δ, which is approximately 1.5 times the reference * tan δ of the pit. It is proposed that the relation between tan δ, and the tan δ specification anticipated in the pit should be used in the decision of the limit f (frequency). The equation for the forementioned decision is simple in that it is composed of basic factors but meets most of the requirements, and it is expected to be useful in estimating the internal state.Next, the basic equation for the internal impedance Z of the pit is derived in a reasonable way, in comparison to the known typical expression for Z. It is shown that the existing expression has a complicated error. The relation between the decision expression for the limit f and the new expression for Z is clarified, and they are shown to complement each other. In other words, the framework for the analysis of the inside of the pit is now completed. The result also provides a new knowledge as to the analysis of the general distributed circuit.
Control of magnetostrictive vibration of amorphous ribbons by magnetic patterns
Authors: Asuke Naoshi , Namikawa Tatsuru , Yamazaki Yohtaro 
Published: July 2007

AbstractA contactless readable medium using a combination of amorphous magnetostrictive ribbon and semihard magnetic material has been investigated. The data are recorded onto the semihard magnetic material, whereas the readout utilizes the fact that the appearance of higher‐order resonant peaks of the magnetostrictive vibration of the ribbon by the application of an ac magnetic field can be controlled by the leakage magnetic flux from the semihard material.The effect of the leakage magnetic flux generated during longitudinal magnetic recording on the semihard magnetic material by MIG head as a localized bias magnetic field has been examined.The results of using a direct magnetic field from a pair of single‐pole heads as a localized bias magnetic field has been further examined; determination of wavelength recorded on the semihard magnetic material also has been done. As a result of observing the power spectrum in the ac magnetic field of the medium combining amorphous magnetostrictive ribbon (Metglas 2826 MB) of 80 × 5 × 0.04 mm3 and semihard magnetic material (CuNiFe alloy) of 100 × 10 × 0.2 mm3, the resonant peak of the amorphous magnetostrictive ribbon has been almost individually detected from the second to fifth orders corresponding to the recorded magnetization patterns.