bluuebunny/crossref_metadata_2025_split huggingface dataset:
Operating frequency range reduction in a series resonant converter
Authors: Muroyama Seiichi , Sakakibara Kazuhiko 
Published: July 2007

AbstractA problem of the series resonant converter is the generation of audible noise under a light load since the operating frequency must be controlled approximately in inverse proportion to the load if a constant output voltage is desired. To reduce this operating frequency dependency on the load, this paper proposes the addition of an auxiliary resonant circuit to the output circuit of the conventional series resonant converter. The characteristics of the proposed converter have been analyzed and confirmed experimentally. It has the following features:

The proposed circuit can maintain constant output voltage by keeping the operating frequency in the range above the auxiliary resonant frequency. Therefore, no audible noise is generated if the auxiliary frequency is selected above the audio frequency range.
In the constant voltage control of the proposed circuit, the level of current necessary to maintain output voltage can be lowered by increasing the auxiliary resonant frequency.
In the range below the auxiliary resonant frequency, the output voltage increases despite decreasing operating frequency. Therefore, it is necessary to control and not operate the circuit in this range.
Characteristics of new types of quasi‐optical diplexers
Authors: Sha Kokusho , Kurashima Hiroyuki , Shoji Toshiaki , Suzuki Michiya 
Published: July 2007

AbstractThe quasi‐optical diplexer presently is considered to be as interesting as a special‐purpose filter, which divides or mixes the electromagnetic waves above microwave frequency in free space. This paper reports on the new types of diplexers: the gridded square, gridded square frame and gridded double square frame types. The feature of these new types is that various frequency characteristics from broad to sharp, can be realized by adjusting independent parameters, and the symmetry or linearity around the resonant frequency can also be realized. This has been difficult in past diplexers. By a systematic experiment, the frequency characteristics of the new types of diplexers are examined. Empirical formulas are derived for the resonant and anti‐resonant frequencies, as well as fractional bandwidth as functions of dimensional parameters. Based on these expressions of the characteristics, the design protocols are presented to meet various requirements. Although there still exists an error in the sense of reproducibility, which is less than 15 percent, the design for the proposed diplexers is established. Thus, the diplexers proposed in this paper have desirable characteristics, which have not been observed in the past. With the detailed design formulas for a wide range of frequencies from roughly 1 to 100 GHz, the diplexers can cope with various requirements, and a diversity of applications can be expected.
A new automatic equalizer for digital subscriber loops
Authors: Ono Shigeru , Kondoh Noriaki , Kobayashi Masaki , Hata Masayasu 
Published: July 2007

AbstractThis paper describes a new automatic equalizer for digital subscriber loops. The new equalizer is composed of a √f equalizer and a BT equalizer. The √f equalizer is a new type of linear equalizer which is based on the approximate theory of exponential orthogonal functions. The BT equalizer is a decision‐feedback equalizer. Subscriber loops can be closely approximated to RC‐dis‐tributed constant circuits. Since the new √f equalizer is composed of a linear combination of RC low‐pass circuits, the required hardware is small in scale. By adjusting the multiplication weights for both the √f equalizer and the BT equalizer, the equalizing characteristics can be controlled continuously. Moreover, since the multiplication weights of the √f equalizer are performed digitally by C‐2C ladder circuits and the main part of the BT equalizer is composed of digital circuits, the equalizing characteristics can be controlled by a digital controller and neither analog multiplication circuits nor analog delay circuits are required. As a result of our trial manufacture and performance tests that were conducted in a 320 Kb/s time‐division burstmode transmission system, it has been verified that this automatic equalizer has sufficient equalizing capabilities.
A numerical calculation method for nonlinear equations from geometrical viewpoints
Authors: Suzuki Yoshihiko , Ueno Satoshi 
Published: July 2007

AbstractNumerical solution of nonlinear equations is studied from a new viewpoint. That is, the concept of conventional solution methods of nonlinear equations which are based on mainly algebraic points of view is derived from the geometrical point of view. In this way, it is shown that various solution methods of nonlinear equations can be unified as determining a one‐dimensional path in the space spanned by the unknowns of the equation. As a result, it was made clear that the differences of various known solution methods come from different choices of this path. By the properties of the rank of the Jacobian matrix Fx of the equation F(x) = 0, the solution algorithms are classified into three types. The proposed solution technique contains a multiple number of parameters in the nonlinear equation. The case of a unique solution is illustrated by a control problem of a multiple‐joint robot arm and the case of a multiple number of solutions is illustrated by a problem that calculates operating points of a nonlinear resistive network.
Synthesis of switched capacitor filters using voltage and charge variables
Authors: Ishikawa Masayuki 
Published: July 2007

AbstractThe switched‐capacitor filter is distinguished by low temperature dependence and small aging effect. In realizing those features in actual filter implementation, the element sensitivity is a problem. In previous construction of the switched‐capacitor filter only the voltages have been considered, which results in limitation of the derived low element sensitivity. In order to improve the circuit with respect to element sensitivity, this paper proposes a construction method using both voltages and charges as the network variables. It is shown first that the basic SC circuit composed of a capacitor and a switch has both the differential‐input property with respect to voltage and the differential output property with respect to charge. By applying these properties, four kinds of integrators are derived. It is shown by computer simulation that the proposed construction, permits enlargement of the range of element sensitivity in cases such as scaling the output of the operational amplifier in the leapfrog switched‐capacitor filter, which has been known as a filter with low element sensitivity. Integrators in which the effect of parasitic capacitance of the original filter is compensated are also discussed.
A frequency–domain design of two–dimensional recursive digital filters
Authors: Hinamoto Takao , Akeno Kazuhiko , Maekawa Sadao 
Published: July 2007

AbstractThis paper presents a technique for the design of two‐dimensional recursive digital filters in the frequency domain. The filter consists of the denominator being structurally stable and the numerator being a mirror‐image polynomial. To find the denominator, a stable two‐dimensional all‐pole filter is designed first so as to approximate the constant group delay specified in each direction. This is done by using the Davidon‐Fletcher and Powell algorithm. The numerator is then designed so that the whole rational transfer function approximates the desired magnitude response under the assumption that the denominator is fixed. This is done by solving a linear equation. The present technique has the advantage of always ensuring the stability of the resultant filter. Two examples are given to illustrate the utility of the proposed technique.
Some location problems on grid graphs
Authors: Yamaguchi Tadashi , Kaji Ikuo 
Published: July 2007

AbstractNumerous works have been reported on the facility location problem to minimize or maximize various objective functions for the locations of one or more facilities on graphs. A general approach to these problems is algorithmic, but solutions are seldom found in an explicit manner. By restricting the object graph to grid graphs, this paper gives solutions in an explicit manner to the center problem and the median problem which are fundamental in facility location problems.Strictly speaking: (i) we derive the relationship between the center and median of general graphs G1 and G2 and the center and median of the product graph G1 x G2; then (ii) we find a multicenter and multimedian of the path graph Pn on n vertices and from the results, solve a kind of multicenter and multimedian problem for grid graphs; and (iii) we solve a distance minimization problem on grid graphs.
Electronic switching system software structure considering virtualizing technique and software components
Authors: Soga Tomiji , Kubota Teruhiro , Ohta Tadashi 
Published: July 2007

AbstractThe stored‐program control system presently forms the main‐stream of the switching control system because of the flexibility in function modifications, compared with the wired‐logic hardware. One of the problems which has manifested recently is the large number of steps of the software modifications, which accompany with the modifications of the switching system architecture and the additions of functions. One of the major reasons for the large number of modification steps is the traditional modularisation, where the switching system architecture and the signaling systems are assumed to be retained. Because of this assumption, the modifications have to be made at various scattered points in the software systems, or have to be made at unexpected points, thereby increasing the number of steps in the modifications. This paper aims at improving the versatility of the software, and describes the modular breakdown, where the modification is localized by making the switching system architecture and the signaling system implicit and virtualized. By the same idea as in the hardware architecture, the software component technique is realized, where the program‐unit is subdivided into a set of units depending on the starting conditions of the programs and a set of units not depending on the starting conditions, and the module is composed by combining those two sets of units. By an example, it is shown that the proposed software architecture is useful.
Phase regeneration characteristic of a three–mode oscillator with second and third harmonic resonators
Authors: Umeda Hiroyuki 
Published: July 2007

AbstractThis paper discusses the phase regeneration characteristics of the three‐mode oscillator with two‐phase PSK signal injection composed of three resonators for the fundamental, second and third harmonics and a negative resistor. As the basic synchronization property of the oscillator, it is shown that two stable phase synchronization modes exist as follows. When the oscillator oscillates synchronously to the fundamental and the third harmonic frequencies, and the external signal with the frequency equal to the second harmonic is injected, synchronization takes place migrating among three frequencies with two stable phases. Then the phase regeneration of the oscillator for the injected phase‐modulated signal is discussed. When the change of the input signal phase is small, the oscillator output phase tends to remain at the original stable phase. When, however, the input phase approaches the other stable phase, the output phase changes stepwise to the other stable phase. Thus, the output signal has the phase fixed to either of the two stable phases. Such a phase regeneration phenomenon is demonstrated by the numerical solution for the simplified equation for the amplitude and phase of the oscillator. Finally, a three‐mode oscillator is constructed which oscillates at the fundamental frequency of 3.5 MHz. It is verified experimentally that the characteristics as analyzed by the theory are realized.
Analysis of sleeve antenna with ground wires
Authors: Taguchi Mitsuo , Egashira Shigeru , Ohzono Tatsuru 
Published: July 2007

AbstractNumerical and experimental studies have been performed on the sleeve antenna. The sperrtopf reduces surface leak currents of the feeder compared to surface currents on the antenna; hence it is confirmed that the feeder does not have a large influence on the antenna properties. Ground wires are attached to the sleeve to match the feeder with the antenna. The effect of the sleeve length, and the length, inclination, and position of the ground wires on the antenna properties have been analyzed numerically and the results compared with experimental results. In the numerical analysis, the feeder is not considered and Galerkin's method was applied to the Poklington integral equation. The 50–Ω input impedance was obtained when the sleeve length is 0.2λ (λ is wavelength), the length of the ground wire is 0.1λ, distance of the ground wires from the feeding point is 0.025λ, and the ground wires are in a horizontal plane; thus the horizontal actual gain is 2.1 dB. This antenna is very useful for mobile radio.
Multiple fir digital filters on a complex integer residue ring
Authors: Murakami Hideo 
Published: July 2007

AbstractThis paper proposes recursive and non‐recursive multiple filters, as a method to realize efficiently a bank of FIR filters on a finite ring. Both types are essentially the application of the isomorphism of the integer residue ring based on the Chinese remainder theorem. For the recursive multiple filter, a bank of filters is realized based on the transfer function defined by z‐transform on the recently introduced complex integer residue ring. Under the isomorphism of the residue ring, the equivalent single filter to the filter bank is realized. For the nonrecursive multiple filter, the number‐theoretic transform on the complex integer residue ring is used to realize the filter based on the equivalence similar to the recursive case. This paper emphasizes the recussive multiple filter. The integer of the form 2n‐1 is proposed as the modulus for the residue operation to be used in the design. The determination of the factors of such an integer and the construction of the residue operation unit are discussed. Finally, the multiple filter is evaluated, and a design example is shown.
Estimation of bit error rate performance of sequential decoding
Authors: Ohashi Masayoshi , Hirata Yasuo 
Published: July 2007

AbstractAn analysis of the BER performance of sequential decoding with stack algorithm is presented for rate 1/2 code. A tight upper bound of BER performance for maximum likelihood decoding is calculated by specific code distance profiles for evaluating the proto error probability of the simulation results. Block error probability is also considered through the random coding theory so that the simulation results satisfy its upper bound. Finally, the coding gain achievable by the sequential decoder is presented for given constraint length of the code and the memory capacity in the decoder, which will be useful for the hardware design.
A low–loss 6–pole canonical dual–mode filter for the output multiplexer of broadcasting satellite transponders in the 12–GHz band
Authors: Nomoto Toshihiro 
Published: July 2007

AbstractThis paper describes the development of a filter for the channel multiplexer in the 12‐GHz band broadcasting satellite transponder with a high transmitting power (above 200 W). The filter for high‐power multiplexer must have a very low loss, to maintain the satellite transmitting power and to secure thermal stability. It was found that the use of a 6‐pole elliptic filter is better than that of a 4‐pole elliptic filter from the viewpoint of the insertion loss and the heat dissipation. The 6‐pole canonical filter is designed using TE113 dual‐mode. In the thermal design, super‐invar with small thermal expansion coefficient is used for the cylindrical waveguides of the filter, and copper with high thermal conductivity is used for the iris plate. Improving the heat dissipation and suppressing the temperature‐rise, the deterioration of the filter characteristics caused by the temperature variation is prevented. The experimental filter realized the insertion loss of less than 0.3 dB, the loss variation of 0.1 dBp‐p and group‐delay variation of 5 nsp‐p within the channel. No significant deterioration of the filter performance was observed through the thermal test of 0°C to 90°C and the high‐power test of 200 W. As a result, it was demonstrated that the proposed filter has better electrical and thermal performance than the previous 4‐pole elliptic filter, being suited as the filter for the multiplexers in high‐power broadcasting satellite transponders.
Design of multirate bandpass digital filters with complex coefficients
Authors: Ikehara Masaaki , Takahashi Shinichi 
Published: July 2007

AbstractThe multirate digital filter is useful in realizing narrowband characteristics because multiplication can be reduced by using different sampling frequencies, at the same time reducing the order of the filter to be realized. This paper introduces the complex coefficient into the traditional design of the low‐pass multirate filter. The construction method is proposed for the multirate bandpass digital filter with complex coefficients. By applying the complex coefficient filters to the decimeter and interpolator composing the multirate filter, bandpass characteristics can easily be obtained. By employing the multistage cascade structure, the number of multiplications and the memory capacity for coefficients can be reduced greatly. Then a new design method for the complex‐coefficient filter is proposed based on the properties of the analytic signal. The discussion in this paper applies to both FIR and IIR filters.
Reflection and transmission of surface acoustic waves at a boundary between metallized and free surfaces on an anisotropic substrate
Authors: Yamada Akira , Shimizu Hiroshi 
Published: July 2007

AbstractThis paper considers the case where the regions of conductor‐deposited surface and the free surface are bordered by a straight line. The reflection and transmission characteristics of the surface acoustic wave are approximately analyzed, which is incident to the boundary. In the proposed analysis, the incident, reflected and transmitted fields near the straight‐line boundary are represented by the linear sums of surface waves, which are a three‐dimensional surface wave in each region with the real and complex wavenumbers, in general. The wavenumber of the surface wave on the substrate is decomposed into the longitudinal wavenumber in parallel to the straight‐line boundary and the wavenumber in the perpendicular direction. The reflection and the transmission coefficients are determined so that the discontinuity of the field near the straight‐line boundary is minimized. As a result, the analytic formula is derived for the reflection and the transmission coefficients, using only the transverse wavenumber of the surface wave. By this elaboration, a simple and approximate method of analysis is presented, which can be applied in general to the arbitrary anisotropic substrate.
Connections of accuracy of least‐square polynomial approximation with degree of polynomials
Authors: Kawaguchi Mayuka F. , Da‐te Tsutomu 
Published: July 2007

AbstractThe least‐square approximation, the minimax approximation, the approximation by partial sum of series expansion and its modifications, are generally used methods of functional approximation, and each has proper advantage for each use. In the case of the least‐square polynomial approximation, the accuracy is expected intuitively to increase as the degree of polynomial is increased, and then reach a ceiling. However, actually, a decrease in accuracy occurs at a certain degree of polynomial when it is run from low to high. As one of its causes, the effect of ill‐condition of simultaneous linear equations in the power series approximation is well known. However, there are phenomena of decrease in accuracy which cannot be explained by the foregoing. To elucidate their causes, this paper shows that the decrease in accuracy as the degree of polynomial increases also occurs in the approximation by orthogonal polynomial in which results are obtained without solving simultaneous linear equations. Also, the differences of the two representative approximations are shown quantitatively by numerical examples. Moreover, the analysis of the cause and experiments on predicting theoretical approximation accuracy by simple formulas are reported.
Extraction of photographic area from document images
Authors: Nakamura Osamu , Koizumi Ichiro , Kikuchi Toshiyuki , Minami Toshi 
Published: July 2007

AbstractIn accordance with the diversification and efficiency promotion of visual communication, various new services have been desired recently. One such service is facsimile which can transmit both black‐and‐white pictures and photographic pictures. However, it is rather difficult to process these two kinds of pictures with a single algorithm. To fulfill the demand for high transmission efficiency and high quality of the reproduced pictures, it is desirable to segment the documents into two categories and process them separately. For this purpose, the extraction of the photographic area included in documents becomes a very important theme.In this paper an extraction algorithm of the photographic area from the document images using the characteristics of edge elements and background gray levels is proposed. The features of this algorithm are: 1( automatic setting of parameters adaptable for each picture is possible; 2) area segmentation corresponding to the various gray levels of backgrounds is possible; and 3 segmentation accuracy is rather high. In the experiment presented in this paper, 125 document images which consist of 512 × 512 pixels with 7‐bit gray levels have been used. The background gray levels of these images are 27, 36, 42, 57 and 77, and into these images photographic images, which occupy 50, 60, 70, 80 and 90 percent of the total area have been inserted. Experimental results show that in every image the photographic areas have been segmented successfully in the sense of practical use. For 93.8 percent of the images, the differences between the inserted areas and extracted areas are only 0 – 7 blocks (0 – 27 pixels), and the usefulness of this algorithm has been proved categorically.
Performance evaluation of mutal overflow routing for hierarchical packet‐switching networks
Authors: Inamori Hisayoshi 
Published: July 2007

AbstractThis paper presents an evaluation of the traffic characteristics of the overflow routing, which is one of the isolated routings (i.e., only the information in the switching station is utilized) of the packet‐switching network. In the overflow routing, the packet selects the first route if the number of waiting packets in the first route is less than the threshold value, and selects the second route if it is equal to or larger than the threshold. Which of the routes is defined as the first route is determined for each destination of the packet, and the packet deroutes others among the routes. In the first part of this paper, the relation between the transmission‐waiting time in the switching station and the threshold of the overflow routing is derived. Then the two‐level hierarchical packet‐switching network is considered, and the mutual overflow routing, SQ + B routing and the stochastic routing, which is easy to realize with simple processing, are compared from the viewpoint of the transmission delay between the transmitting and receiving stations; SQ + B routing has the best performance in the isolated routings, and the stochastic routing features in the simple processing and the easy representation. As a result, it is shown that the transmission delay in the mutual overflow routing is less than in the stochastic routing and is nearly the same as that of SQ + B routing. Since the processing per packet in the mutual overflow routing is less than that of the SQ + B routing, the mutual overflow routing can be considered as the best among the three routing methods.