bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insertion loss and TTE of SAW filter using 3‐transducer configuration
Authors: Setsune Kentaro , Wasa Kiyotaka 
Published: July 2007

AbstractThe use of a 3‐transducer SAW element configuration gives complete suppression of the triple‐transit effect (TTE) at the frequency at which the external circuit is electrically matched to the central transducer. But when designing such an element as a filter it is necessary to deal with TTE at all frequencies within the filter band. This paper discusses the TTE within the filter band for an element with a 3‐transducer configuration, assuming negligible SAW reflection. The significance of the impedances of the external circuit and the interdigital transducer, the electromechanical coupling coefficient of the substrate and the relation between bandwidth and insertion loss in obtaining 40 dB or better TTE suppression in the main signal is demonstrated. In particular, a TV‐VIF filter with the regular 3‐transducer configuration prepared on a thin‐film ZnO substrate gave 40 dB of TTE suppression in the filter band and had 11 dB insertion loss. A device with a proportional band for use in a TV‐VIF filter was prepared in order to test the theoretical calculation. The TTE and main response signals were separated by means of a pulse modulation set‐up. The TTE frequency response within the filter band was observed directly, and the 3‐transducer configuration was found to be capable of producing the low‐loss filters needed for band design without alteration of commonly‐used design methods, and is an effective method of achieving TTE suppression.
The Runge‐Kutta method with Arcs of equal length and its applications
Authors: Fukuda Kaoru , Nagashima Hideyo 
Published: July 2007

AbstractThe Runge‐Kutta method, a popular numerical procedure for solving a differential equation, is based on Taylor series expansions of the solution. It provides the solution if the function is single‐valued. However, it is difficult to obtain the solution in the case of a multivalued function. In this paper, a coordinate system that follows the shape of the solution is introduced for developing a numerical solution of a differential equation with a multivalued functional solution. For a step describing accurately the shape of the function, the arc length of the solution function is used. the Runge‐Kutta method with arcs of equal length is proposed in which the arc length is kept identical. From the error formula for the Runge‐Kutta method, the condition is shown under which the solution by the proposed method is more accurate than the one by the conventional Runge‐Kutta method. Next, a numerical method for a differential equation with a multivalued solution function is given by combining the new Runge‐Kutta method and the coordinate transformation. This transformation is applied not only to numerical values but also to the differential equation itself. This process can eliminate the points at which the function on the right‐hand side of the differential equation becomes singular and provide solutions even when the solution function is multivalued.
Selection of state variables for locally solvable nonlinear networks
Authors: Suzuki Yoshihiko 
Published: July 2007

AbstractThis paper considers the necessary and sufficient condition for the state variables for locally solvable nonlinear networks to be capacitor currents vector iC and inductor voltages vL, (iCT, vLT), instead of capacitor charges vector q and inductor fluxes vector ψ (qT, ψT). the condition is given by the regularity of matrix K and |ta, vj|→∞ as |e, j|→∞ in the resistance network where all the capacitors and inductors are replaced by voltage sources e and current sources j, respectively. Here, ie and vj are the voltage source current and current source voltage, respectively.As a result, in the networks where (qt, ψt) can be transformed into (iCT, vLT), the network dynamics can be described in the same way as in a linear system and global consideration on networks can be done only by investigating the property of matrix KA. For example, the sufficient condition for the equilibrium point to be globally asymptotic‐stable is given comparatively easily, the consideration on eventual passivity can be done easily, and, in general, there exist various analysis methods such as in the case where (qT, ψT) are used as state variables.
Analysis of the M/G/1 and GI/M/1 queueing systems by the supplementary variable approach
Authors: Nogami Shinya , Komota Yasuo , Hoshiko Yukio 
Published: July 2007

AbstractStudies on the analysis of M/G/1 and GI/M/1 using the supplementary variable approach have already been reported. However, there has been no study which analyzed consistently the systems from the transient state to the steady state.Using the remaining service time of a customer being served in the M/G/1 and the residual interarrival time in the GI/M/1 as supplementary variables, we derive the basic equations of state probability density functions and state transition probability density functions which describe the behavior of the systems and the transient distributions of characteristic quantities, such as queue length, virtual waiting time, etc. the transient solution is derived as a solution of certain initial‐value‐ and boundary‐value problems. Using this solution, the transient solutions of the characteristic quantities (including queue length, virtual waiting time, mean queue length, mean virtual waiting time, etc.) are derived. Furthermore, by applying the final value theorem of Laplace transform to these results, we obtain stationary distributions of the characteristic quantities which equal those results obtained by imbedded Markov chain analysis.
A wiring problem on single‐layer printed circuit board without mounting modules upside‐down
Authors: Masuda Sumio , Kashiwabara Toshinobu , Fujisawa Toshio 
Published: July 2007

AbstractIn some cases of realizing a circuit on a single‐layer printed board, all modules are mounted on the same side of the board. This paper proposes an algorithm, assuming that a circuit contains modules which cannot be mounted upside‐down, to determine whether or not a single‐layer printed wiring is possible under the following two restrictions: (i) the modules can be mounted only on the specified side of the board; (ii) wiring should not be made under the module. the notion of PQ tree is extended as the data structure in the proposed algorithm, and the computational time is proportional to the total number of terminals in the circuit.
A surface current detector for high‐frequency currents on a metal surface
Authors: Nagasawa Yoji , Sato Risaburo 
Published: July 2007

AbstractIt is very important from the viewpoint of environmental electromagnetic engineering to detect vectors of high‐frequency currents on a metal plate (high‐frequency surface currents). In this paper, a high‐frequency surface current detector has been realized based on the coupling theory between an electromagnetic plane wave and a wire above the earth, and by modelling this arrangement. For the modelling, it has been considered that the electric field is approximately perpendicular to the metal plane in the space near its surface due to the surface currents flowing along the plate; and that the magnetic field is parallel to the metal plane. In practice, the pointing vector carried by the magnetic field is measured. It has been confirmed that the detector actually made can detect the vectors of surface currents by detecting progressing waves generated along a metal plane. the coupling coefficient between the surface currents and detector has been obtained experimentally by varying the parameters of the coupling line.
Formation of an evaporated thin‐film CdSe rectifying barrier by controlling the deposition rate
Authors: Yuasa Yasuhito , Ema Yoshinori , Hayashi Toshiya 
Published: July 2007

AbstractThe formation of a rectifying barrier using the variation with deposition rate of the resistivity of the evaporated thin CdSe film is described. Characteristics of the devices are measured and compared with the theoretical values.Substrate temperature is maintained at room temperature during the deposition. For a deposition rate of 11.5 Å sec−1, the film has an excess of Cd and therefore exhibits n+‐type characteristics with a resistivity of 0.05 Ωcm. On the other hand, for a deposition rate of 20.0 Å sec−1 the film exhibits n‐type characteristics with a resistivity of 0.25 Ω cm. the structure of the device is as follows: an Au film is first deposited on a glass substrate, and a CdSe film, 3200 Å in thickness, is then formed at a high deposition rate (n‐type) and, subsequently, CdSe of 4450 Å thickness is formed at a low deposition rate (n+‐type). Finally, an Au film is deposited on top of the CdSe film in the final stage of formation of the device. the forward‐bias voltage of the device rises at 0.25 V and the reverse‐bias voltage is 3.5 V. Further, the index number of the forward‐rectifying characteristics is calculated to be 1.99, indicative of a good device. Moreover, the capacitance and temperature dependence of the I‐V characteristics are measured and are used to explain the properties of the device, using diffusion theory. As a result, the barrier height from the metal side is 0.54 V, the diffusion voltage is 0.48 V and the depletion layer (at OV) is 895 Å.
Optronic controllable functions of S‐type negative resistance circuits using photocoupled FETs
Authors: Takahashi Haruo 
Published: July 2007

AbstractThe photocoupler has been widely used as an interface element for circuit coupling functions. A light‐emitting diode is used on one side and the second side consists of an FET‐optocoupler. This combination of elements can be used as an optronit controllable device which exhibits optically controlled negative resistance characteristics.A negative resistance circuit consisting of a combination of two photocouplers is discussed and a reversible switch in this circuit capable of flip‐flop switching is experimentally demonstrated. A negative resistance circuit with bilateral characteristics that are independent of the polarity of the applied voltage is also proposed. This circuit can control the polarity selection of the negative resistance characteristics, depending on the external light. Phase control of the starting AC voltage, as well as oscillation control of a bilateral relaxation oscillator circuit are discussed on the basis of the experimental results.
Fundamental theory on regeneration of high‐quality image
Authors: Iijima Taizo 
Published: July 2007

AbstractIn many cases of image description, it is often required to maintain high distinctivity to deal with the dissolving ability of the human eye. However, since ordinary images contain high redundancy, in the processes such as storage, transmission and processing with which a human operator is not concerned directly, it is desirable to compress the image information into the least but necessary size to achieve efficiency. In this paper, we attempt to establish a rational theory when a high‐quality image containing redundancy is reconstructed from compressed image information. We have obtained a reconstruction theory for a high‐quality image as well as a concrete formula to reconstruct an image by an interpolating polynomial. Thus, it seems to be useful to apply the results of this paper to establish an image processing technique to make many practical images, such as TV images, facsimile images, CT images, of high quality.
Reliability of arc‐fusion spliced fiber with a reinforcing element
Authors: Matsumoto Michito , Haibara Tadashi , Miyauchi Mitsuru 
Published: July 2007

AbstractDue to the fact that optical fiber cable technology is entering the stage where it can be of practical use, the need to improve the reliability of the arc‐fusion spliced parts of fibers has become important. Although the improvement in the strength of the spliced parts of fibers has been studied and various methods of reinforcing them have been developed, to date, the breakdown mechanism of the fibers within their reinforcing elements has not been analyzed sufficiently. In this paper, the “pushing out” of a fiber from its “coat” and the transmission of torsion of a fiber within a reinforcing element have been examined. These have not been considered before as types of stress acting on an arc‐fusion spliced part of a fiber. It has been found that fiber breakdown is caused by the combined effect of a buckling stress due to fiber pushing out and a torsion stress. It has been found also that reinforcing the spliced parts of a fiber with a heat‐shrink tube is a highly reliable method having excellent characteristics for preventing the pushing out and torsion of the fiber. A spliced part of the fiber, which has been reinforced with a heat‐shrink tube, also has an excellent light transmission characteristic. For example, transmission loss at the spliced part is only 0.02 dB at −70°C.
Phase matched optical dielectric waveguide using the artificial anisotropic structure
Authors: Mizumoto Tetsuya , Naito Yoshiyuki 
Published: July 2007

AbstractBirefringent material in a thin film dielectric waveguide is used to realize phase matching of the waves with different polarizations. However, this method cannot be used exclusively due to lattice mismatch as happens in a mode conversion type isolator. This paper proposes an artificial anisotropic waveguide realizing phase matching with isotropic dielectric materials only. the structure is a slab waveguide loaded with dielectric strips parallel to the wave propagation direction. This structure can equalize the phase velocities of the Ex and Ey modes. A numerical analysis based on the mode matching technique is used to obtain the phase match condition. the effect of an artificial anisotropy is confirmed in a waveguide fabricated in experiments. A waveguide is realized in which difference of the propagation constants of the Ex and Ey modes is extremely small. It is believed possible that a thin film optical isolator can be reproduced with this waveguide.
Applications of wave digital filters to branching filters with low coefficient sensitivity
Authors: Suzuki Masatoshi , Wakabayashi Hiroyuki , Miki Nobuhiro , Nagai Nobuo 
Published: July 2007

AbstractWave digital filters made to imitate the behavior of doubly terminated lossless filters (resistance terminated reactance circuits) are a class of digital filters with low coefficient sensitivity. A wave digital filter can realize not only an input‐output transfer function, but also an input reflection coefficient of the doubly terminated lossless filter. However, so far, almost no consideration has been given to the realization of the reflection coefficient by wave digital filters. This paper shows that wave digital filters can be applied to branching filters, narrowband eliminate filters and multibranching filters by utilizing two transfer functions of wave digital filters. Some examples show that these filters composed of wave digital filters can be realized with fewer multipliers and have low coefficient sensitivity properties.
A design method for low‐pass filter using nonuniform transmission lines
Authors: Kobayashi Kunikatsu , Nemoto Yoshiaki , Sato Risaburo 
Published: July 2007

AbstractThis paper presents a design method for the low‐pass filter using nonuniform transmission lines. First, two kinds of nonuniform transmission lines are considered‐parabolic and exponential lines. the strict and low‐frequency approximate solutions are determined for two kinds of nonuniform lines and the mixed lumped and distributed circuit consisting of parallel capacitors and uniform transmission lines. By equating those two kinds of solutions, an approximate expression is obtained for the nonuniform line made up of mixed lumped and distributed circuit. Then by using this approximate equivalence relation, sections of pre‐designed lumped and distributed circuits are approximately replaced by nonuniform lines. Due to the replacement by approximate elements, the resulting circuit has characteristics different from the original lumped and distributed circuit. It was seen from several numerical examples that the circuit made up of nonuniform lines has steeper roll‐off characteristics and larger attenuation in the stop‐band than the lumped and distributed circuit and are suited for a low‐pass filter. It is observed also that the circuit made up of nonuniform lines can reduce the number of lumped capacitors more than the lumped and distributed circuit.
Coated optical fiber for high strength splice
Authors: Kukita Shigezo , Kimura Takao , Nihei Fumihiro , Sakamoto Akira 
Published: July 2007

AbstractIntroduction of optical fibers into subscriber loops requires further improvements in the structure of coated fibers presently in use. Further improvements are required also in a splice technique which ensures simple installation and reliable system performance in various environments. the present coated‐fiber structure rquires removal of all coatings in the splice which degrades splice strength. This paper describes a new coated fiber structure which allows splicing without removal of the primary coating. This has improved the strength by a factor of two as well as splice time by a factor of three. This structure also showed optical transmission characteristics which are comparable to the conventional coated fiber.
Numerical analysis of the horizontal antenna above a lossy ground
Authors: Nakagawa Kinsaku , Inagaki Naoki 
Published: July 2007

AbstractSince the electric field integral equation for the horizontal antenna above a ground contains a kernel of the form δ2/δxδz f (x, z) derived from the vertical Herz potential, its numerical integration is difficult. In this paper, it is shown that this kernel can be transformed to the form δ2/δx2 g(x, z) so that the moment method can easily be introduced without approximation of the kernel by the reflection coefficient method (RCM). Numerical calculations have been performed for the input impedance and the radiation pattern of a half‐wave antenna above a typical lossy ground at 60 MHz in terms of height, relative dielectric constant and conductivity as well as the thickness parameter ω. the resistive part of the computed input impedance agrees almost with the value by the RCM, whereas the discrepancy between two methods increases in the reactance for a fatter antenna if the antenna height is less than about 0.4 times the height. the input impedance vs. the ground conductivity varies abruptly near the transition σ = ωϵ0ϵs from capacitive to conductive nature in the ground. If the height is half wavelength, the H‐plane pattern has the main radiation direction at 62 degrees and hence long‐distance communication is possible by ionospheric reflection. In the case of the ground, about ‐9 dB of the electric field in the maximum direction remains near the zenith and the beam is different from that for perfect conductor cases.
Digital delay locked loop
Authors: Kuroda Akihiro , Nakagawa Masao 
Published: July 2007

AbstractIn spread spectrum communication systems, Delay Locked Loops (DLL) are used widely for synchronizing the spreaded signal, which is the most important part at the receiver side. However, the conventional DLL's are all analog ones. Considering reliability, compactness and programmability, the DLL's are well worth digitalizing. In this paper we propose a new digital DLL. This loop has concise constitution and good performances.
Analysis of strip‐line circuit by planar circuit approach—Application of higher‐mode impedance concept
Authors: Hsu Jui‐Pang , Anada Tetsuo 
Published: July 2007

AbstractTriplate‐line circuit and strip‐line circuit are the circuit structures used frequently at microwave and millimetric wave frequency bands. In these frequency bands, the strip‐line width is not negligible compared with the wavelength. Also, the presence of electromagnetic field disturbance at junction and the mutual interaction of the frequency bands has strong effects on frequency characteristics. In this paper, to treat this kind of problem, the strip transmission line circuit is modeled and it is shown that the electromagnetic field distribution in this model is determined by the planar circuit equations. In solving these planar circuit equations, the circuit is separated into transmission line and junction circuit, and the mode impedance for each circuit is derived. It is shown that the input/output characteristics of the strip‐line circuit are obtained by making analogous circuit equations conventional equations and solving them. This method of analysis is applied to a simple triplateline circuit and its wideband frequency characteristic is calculated for dc 18 GHz. Furthermore, the corresponding circuit is constructed and its frequency characteristic is measured for 4 ± 18 GHz. Since the calculated results based on this method of analysis agrees well with the measured results, the validity of this method of analysis is confirmed.
A new maximum likelihood decoding of high rate convolutional codes using a trellis
Authors: Yamada Takahiro , Harashima Hiroshi , Miyakawa Hiroshi 
Published: July 2007

AbstractMaximum likelihood decoding of convolutional codes by Viterbi decoding method is an effective error correcting technique. However, little study on Viterbi decoding of high rate codes has been done since the number of paths entering each trellis state increases as the code rate increases. This paper presents a new maximum likelihood decoding of convolutional codes of rate (n ‐ 1)/n using a trellis. the trellis is drawn according to the state transitions of the syndrome former of the code, and has only one or two paths entering each state rather than 2n‐1 paths as in the case of conventional trellises. Thus, we can replace the 2n‐1‐ary comparisons at each state needed in the conventional Viterbi decoding for the code of rate (n ‐ 1)/n by binary comparisons. the implementation of maximum likelihood decoders for high rate convolutional codes is simplified greatly by this approach. Moreover, this decoding method shows the same performance as that of conventional Viterbi decoding method from the viewpoint of selecting the maximum likelihood code sequence.
Characteristics of microwave power absorption in an insect exposed to standing‐wave fields
Authors: Fujiwara Osamu , Goto Yoshiyuki , Amemiya Yoshifumi 
Published: July 2007

AbstractIn the study of microwave biological effects, microwave irradiation experiments with pupae of insect (Tenebrio molitor) are performed actively. Experiments of this kind showed that the developmental anomalies produced by microwave irradiation on the pupae can not be explained simply by only the thermal effect. As a result, there has been considerable discussion on the nonthermal effects of microwaves. Among the many experiments, Olsen's 6‐GHz band standing‐wave irradiation experiment is noteworthy because it ignores the above nonthermal effects in that developmental anomalies depend only on the absorptive ability of the pupa. In a standing‐wave experiment performed using the 2 GHz band, the result differed from that in the 6 GHz band. Thus we observed that the heating pattern distribution within a pupa is related to developmental anomalies. Using this prospective, this paper analyzes the absorbed power in a pupa exposed to microwave standing‐wave electromagnetic fields and clarifies the characteristics of the absorbed power to the frequency as it relates to exposure locations. the results showed that a pupa can be exposed to an approximately uniform electromagnetic field separated into individual components of the fields in the 2 GHz band; however, this does not hold in the 6 Hz band. Moreover, distribution of heating potential (absorbed power per unit volume) within a pupa differs remarkably between the two frequency bands.