bluuebunny/crossref_metadata_2025_split huggingface dataset:
A rocket‐borne antenna consisting of a monopole and a major angle corner reflector
Authors: Kamata Yukio , Ichikawa Mituru , Hayashi Tomonao 
Published: July 2007

AbstractThe radiation pattern of a major angle corner reflector in the magnetic plane is close to uniform in a broad range (broad radiation pattern) and a reasonable front‐to‐back ratio can be obtained. Since the configuration also is simple, it is considered useful as a rocket‐borne antenna. This paper describes the development of the antenna based on a dipole with a major angle corner reflector as an S band (2290 MHz) rocket‐borne antenna. To satisfy the conditions (small, lightweight, mechanically strong and thermal resistant) for a rocket‐borne antenna, the antenna element is made of a monopole buried in teflon (with a relative permittivity of ϵr = 2) so that the structure is small.The radiation characteristics with respect to various parameters are computed numerically for a basic major angle corner reflector antenna. Based on this result, the radiation characteristics with respect to the aperture angle of the experimental model antenna are derived. From these results and the conditions for the rocket‐borne antenna, an optimum design is carried out. From the experiment, it is confirmed that the present antenna has an extremely broad radiation pattern and a superior radiation characteristic to the back side of the rocket.
Design and electrical characteristic evaluation for interface circuit in isdn bus wiring system
Authors: Nakano Shizuo , Nagai Naofumi 
Published: July 2007

AbstractISDN basic access interface provides transmission capability of two B channels and one D channel for various telecommunications services. The electrical characteristics of this interface are strictly regulated in CCITT recommendation I.430 to allow up to eight terminals to be connected in a bus wiring system. This paper describes a design method for achieving desired line interface characteristics, including output voltage with specified loads, transmitter output impedance at inactive state, receiver threshold voltage and cut‐off frequency of a low‐pass filter. The electrical characteristics of the line interface circuit based on the proposed design are measured by using practical bus wiring systems and are confirmed to satisfy recommendation I.430.
An adaptive phase‐control digital pll
Authors: Kubo Hiroshi , Iizuka Ikuo 
Published: July 2007

AbstractWith the recent development of digital LSI integration, numerous studies have been made on the digital implementation of the phase‐locked loop (PLL). Among those, the binary quantized digital PLL, which is simple in circuit structure and the multilevel quantized digital PLL which is an extension of the forementioned type are considered interesting.This paper proposes a new type of sequential loop filter (SLF) for the multilevel quantized digital PLL by which the tracking range can be expanded. As in the case of the random‐walk filter, the general idea about SLF has been to control the output phase by smoothing the result of phase comparison. Consequently, when the input frequency of the phase information, mark ratio is low, it has been difficult to keep a wide tracking range for any extent of the frequency offset.In the proposed SLF(APCF) (adaptive phase‐control fitler), in contrast to the smoothing process, an adaptive search of the phase‐control interval is made by applying the steepest descent method to the result of phase comparison. In this paper, the algorithm of APCF is described first and the evaluative expressions of the performance are derived theoretically.Some evaluations are given to compare adaptive phase‐control filter with the conventional sequential loop filter by simulation. It is shown that the output jitter for the low mark‐ratio is small and the degradations such as the reduction of the tracking range are small even if the mark‐ratio is decreasing.
Optimum adaptive equalization of selective fading channel based on time‐varying channel model
Authors: Munemura Koichi , Ogiwara Haruo 
Published: July 2007

AbstractThe time‐varying transmission characteristics, as in the case of the selective fading channel, are modeled. Based on the model, the optimum adaptive equalization is proposed considering the speed of variation. Proposals have already been made on this problem for the case of the baseband transmission.This paper extends the results to the case of band transmission and discusses several points which have not been covered in previous studies. First, the model is extended to the case where the overall system including the channel is the band transmission, and the adaptive equalization algorithm is derived using the complex Kalman filter. A simulation based on the model is executed.The tolerable range is determined for the frequency deviation between the carrier and the local oscillation considered as a cause of the deterioration of the performance, along with the variation of the transmission characteristics. To suppress the effect of the decision error in the decision feedback equalization, the training procedure periodically is combined and the effect of the method is analyzed.Finally, the effect of the deviation between the model parameter of the channel characteristics and the equalizer is examined, the tolerable range is determined, and the usefulness of the algorithm is demonstrated.
Congestion control for bursty video traffic in ATM networks
Authors: Kubota Kouji , Murata Masayuki , Miyahara Hideo , Oie Yuji 
Published: July 2007

AbstractIn an ATM network, congestion controls as well as traffic controls, e.g., call admission control and policing control, are important to efficiently transmit multimedia traffic while satisfying their different required grade‐of‐services.This paper analyzes a congestion control scheme required for ATM networks. With the control scheme, when the buffer queue length in an ATM switch exceeds a certain threshold, congestion control is applied and. cells from lower priority traffic such as voice are rejected. As a result, higher‐priority traffic such as compressed video can be transferred with good quality.Cell loss probabilities are analyzed for each multimedia traffic at a switching machine buffer and the effectiveness of the congestion control is studied. By numerical examples it is shown that the threshold value to apply the congestion control is an important parameter for effectively transferring multimedia traffic.
Passive reflector to reduce fading due to angle‐of‐arrival variation on microwave links
Authors: Komai Tomohiro 
Published: July 2007

AbstractA passive reflector is used as a simple repeater system to connect transmission and reception points with no direct line of sight. When the wavelength is short and the reflector has a large structure, the radiation characteristics of the reflector exhibit sharp variations. A phenomenon such as fading is introduced when the direction of the wave incident on the reflector is bent due to a change of the atmospheric refractive index or the angle of arrival varies due to the vibration of reflector by wind pressure.This paper proposes a reflector structure which is made from element reflectors whose positions are displaced slightly and the depth of nulls in the radiation pattern appearing in horizontal and vertical planes can be reduced. Moreover, the radiation pattern of the proposed structure and its relationship with the position of element reflectors and the reflector gain are clarified. The experiments were performed at the reflector repeater stations where the received electric field fluctuations occurred quite frequently and the wave bending was confirmed by the measured field fluctuations. Moreover, by making the reflector structure as proposed here, the field fluctuation width may be suppressed and the validity of this method is demonstrated.
Recent spreading codes for spread spectrum communication systems
Authors: Tachikawa Shin‐Ichi 
Published: July 2007

AbstractThis paper presents recent spreading codes and their applications to spread spectrum (SS) systems.First, co‐channel interference in spread spectrum multiple access communication systems (SSMA) and cross‐correlation functions are described, and the relationship between new “No sequences” with low cross‐correlations and other well known sequences is summarized.Second, an SSMA using very low‐rate convolutional codes proposed by Viterbi is described. With this SSMA the spectral efficiency can be improved over that of FDMA using a guardband.Finally, optical orthogonal codes for fiber networks, orthogonal Gold sequences, orthogonal Bent sequences for synchronous SSMA, majority logic combination sequences using M‐sequences, and generalized Geffe sequences for rapid acquisition are described.
A digital multisignature method for facsimile‐mail service
Authors: Tanaka Kiyoshi , Nakamura Yasuhiro , Matsui Kineo 
Published: July 2007

AbstractIn the wake of the development of computer‐aided facsimile equipment, office documents may be digitized, circulated on a network, and in the near future stored into files as soft copy. In this paper, we call this type of service facsimile‐mail, and we discuss a multisignature method which is applied to facsimile documents. This method makes it possible to sign digital documents multi‐plexively and simplify the document exchange process. Document management is simplified and the reliability of the network is improved.
A code division multiplex using manchester‐coded orthogonal sequences
Authors: Habuchi Hiromasa , Hasegawa Takaaki , Hakura Yukio , Haneishi Misao 
Published: July 2007

AbstractThere has been increasing interest recently in code division multiplex (CDM) systems. The authors reported a CDM system using pseudo‐orthogonal Manchester‐coded M‐sequence pairs. For this CDM system, the effective energy per bit in the received signals is reduced (M + 1)/2M times as much as the transmitted energy per bit. Moreover, the bit error rate (BER) of the 3M‐plex system, which uses the “a‐chip‐shift” multiplex operation alone, does not converge on zero even if Eb/N0 increases.This paper proposes a CDM system using Manchester‐coded orthogonal sequences which consists of an M‐sequence M chip and an additional chip. The proposed 3M‐plex system is a combination of the “a‐chip‐shift” multiplex operation and the amplitude multiplex operation. The proposed systems do not have loss of the effective received signal energy. The BER of the proposed systems converges to zero with increasing Eb/N0. Moreover, the proposed system out performs the Manchester‐coded multilevel transmission system.
A study of the distortion and propagation time‐delay of Loran‐C pulse wave based on a model of the propagation path
Authors: Kouguchi Nobuyoshi , Sato Masashi , Morinaga Norihiko 
Published: July 2007

AbstractThe main cause of the absolute positioning error in the Loran‐C system is in the occurrence of the propagation time delay error caused by the fact that the propagation speed of the pulse signal on the actual propagation path is different from that assumed in the formation of the Loran‐C maritime chart. The propagation path characteristics not only cause the propagation time delay of each received pulse signal but also generates waveform distortion in the received pulse. Hence, it is possible to estimate the propagation delay time by means of this waveform distortion.At present, a measure of the distortion of the pulse waveform distortion of the Loran‐C is envelope to cycle difference (ECD). In this paper, as a new measure for the pulse‐wave distortion to estimate the propagation time delay, CHACLE, or change of half‐cycle length, is proposed.A method for correction of the absolute positioning error is provided based on the estimation of the propagation time delay from the measures of the wave‐form distortion (CHACLE and ECD) by means of the simplified propagation path for an easy analysis and of the general propagation path. It is demonstrated that CHACLE is superior to ECD in terms of the effect of correction. Further, to confirm the validity of the correction method proposed in this paper, the present method is applied to a propagation path model resembling the mixed propagation path used in the United States to estimate the pulse time delay. It is confirmed that the absolute positioning error can be reduced to less than about 20 percent.
Wideband hybrid diplexer using ridged waveguides
Authors: Ishida Osami , Miyazaki Moriyasu , Isota Yoji 
Published: July 2007

AbstractTo develop a broadband diplexer to be used for the Ku band satellite communication earth station, a hybrid diplexer is proposed based on the branch waveguide directional coupler in which the main and auxiliary waveguides are ridged waveguides. The theoretical discussions and experimental results are described.First, the characteristics of the hybrid diplexer and those of the constituent components are expressed in terms of the scattering matrix so that the effect of the hybrid coupler is presented. Next, the characteristics of the branch waveguide directional coupler used as a hybrid coupler are studied theoretically. It is pointed out a broadband operation is possible by the use of ridged waveguides for the main and auxiliary waveguides. Further, using the transmit and receive diplexer for the Ku band satellite communication earth station as an example, the design and fabrication have been carried out to demonstrate the validity of the theoretical results.
A characteristic of primary distributed‐type switching network
Authors: Takase Juhro 
Published: July 2007

AbstractThis paper considers the primary distributed‐type switching network which serves as the prototype for the distributed switching network. A method is shown to determine the route with the minimum number of tandem stages from the originator to the destination nodes in the network (called shortest route). The shortest route is given either by the straight path directly connecting the originator and the destination switching nodes, or, if such does not exist, by the following path.Consider the parallelogram that directly connects the originator and the destination switching nodes. Then the route is obtained from the originator switching node to the destination switching node by connecting arbitrarily the unit links on the border and the inside of the parallelogram, in the same direction as that of the edges of the parallelogram from the originator switching node to the destination switching node. The number of shortest routes between the originator and the destination switching nodes increases following the exponential function of the distance between the originator and the destination switching nodes. The number of tandem stages in the shortest route increases linearly with the distance. If a honeycomb‐type network is employed, the number of tandem stages in the shortest route can be reduced by approximately 15 percent at the maximum, compared to the grid‐type network. When a failure such as blocking is produced between the originator and the destination, there exist three kinds of shortest routes depending on the point of generation.
Fundamental study on optical fiber direct transfer splicing
Authors: Kobayashi Hideo , Ueno Kouji , Watanabe Ichirou , Uenoya Takuya 
Published: July 2007

AbstractWith regard to the direct transfer splicing of optical fibers in which the fibers are cut, moved, and spliced to other fibers at arbitrary locations along the line, the results of basic investigations on fiber vibrations when the fibers are cut and moved are presented. The solution method of the fiber longitudinal and lateral vibrations due to the tensile force and bending moment exerted when it is cut is indicated. The relation among fiber length, tensile force, settling time of vibrations, and loss variations are clarified.With regard to the behavior of fiber movement, the solution method of the lateral vibrations when one terminal is fixed also is presented and the relation among movement speed, fiber length, and settling time is determined. From these investigations, the requirements under which the loss variations associated with fiber cutting and its movements can be kept below 1 dB are clarified.
Design of a PSK modulation/demodulation method free from interruptions
Authors: Yamazaki Masami , Tomoda Yusuke , Takahata Fumio 
Published: July 2007

AbstractThis paper discusses a PSK modulation/demodulation method free from interruptions providing continuous telecommunication services. The feature of the system is that the transmission rate or the carrier frequency is switchable without interruptions during communications. Functions of the system are outlined. The design procedure and design results are presented.Another feature of the proposed method is its transmission format. In the normal operation, a control information is inserted into the transmission format and a preamble is inserted only when the transmission rate or the carrier frequency is to be changed. By this elaboration, interruptions can be avoided.As a detailed example of the design, a link configuration is assumed where the convolution encoding Viterbi decoding with coding rate of one‐half is used as the forward error correction scheme, and the information rate is made variable among 2B + D, B + D, and D based on the basic ISDN service. Parameters concerning the transmission format and the modulation/demodulation are determined. The control information and protocol required in the functional switching needed in avoiding interruptions are also discussed. By this method, limited radio frequency resources can efficiently be utilized, appropriately varying the transmission rate according to traffic or switching the carrier frequency.
Digital cross‐connect system control algorithm for reducing rearrangement needs
Authors: Fujii Nobuo 
Published: July 2007

AbstractThe digital cross‐connect system (DCS) employs cross‐connect equipment composing the synchronized digital network. The scale of DCS is enlarged using the rearranged‐type TST switches based on the nondisturbing rearrangement control algorithm.This paper considers the case where DCS is controlled using the proposed rearrangement pattern search algorithm. A control algorithm is proposed which can avoid the generation of a blocking state, thereby necessitating the rearrangement control, and can realize the nondisturbing rearrangement control when a blocking is produced. The effectiveness of the method is demonstrated by computer simulation.In this paper, knowledge in other studies such as the mechanism of block generation is summarized. Then an evaluation measure is introduced for the S switch state. A control algorithm is proposed which suppresses the generation of the blocking by selecting the S switch timeslot to maximize the evaluation measure. It was verified by the computer simulation that the generation of the rearrangement control is reduced by approximately 5 to 30 percent, depending on the switch structure, compared to the algorithm that minimizes the evaluation measure for the switch. A nondisturbing control method for the switch also is presented.
An intelligent network call model incorporating broadband isdn controls
Authors: Wakamoto Masaaki , Fukazawa Mitsunori , Kim Moo Wan , Hattori Shinmi 
Published: July 2007

AbstractIntensive research and development efforts have been made on the intelligent network (IN) to realize diversified and advanced telecommunication services and the early introduction of new services under a multi‐vendor environment.Earlier research and development, however, assume the conventional telephone service and narrowband ISDN services and gave little consideration to the broadband ISDN.The study of the IN from the viewpoint of the broadband ISDN is urgent considering the systematic realization of the services (i.e., multimedia services) that are not yet sufficient as well as the increase of the demand for the development of new services.This paper proposes the call model, which provides the basis for realizing the IN architecture incorporating the broadband ISDN. First, the basic concepts are defined clearly. Then the call model is proposed which can realize the general connection control for various connection types as well as the flexible control for the multiple virtual channels in the multimedia environment. The model also facilitates the control of the interactions among related services. Finally, the service control characteristics of the proposed call model are investigated.
Distribution of positioning error in a global positioning system
Authors: Okuda Kuniharu , Yasuda Akio 
Published: July 2007

AbstractThe distribution of the positioning error in a global positioning system (GPS) depends on the allocation of satellites. Thus, the agreement between the covariance ellipse derived from the allocation of satellites and that derived from the positioning error distribution of the actually measured data is examined for two reception systems, i.e., the sequential and the parallel processing systems. The result shows that the two covariance ellipses agree well, although the situation depends a little on the shape of the ellipse as well as the azimuth and elevation of the satellite.The size of the ellipse is approximately one‐half in the parallel processing system compared to that of the sequential one. It is proved by the results of the analysis that the distribution of the error is anticipated before the measurement or the positioning during navigation and is represented by an ellipse. The method is applied to a navigating ship. It is shown that the display of the error distribution together with the positioned point is useful to the navigator in determining the steering of the ship in the sense that the reliability for the position of the ship is increased.
Bit error rate and power penalty of optical dpsk communication systems with echo
Authors: Yamaguchi Yoshiaki , Takeda Shinichi , Hiranos Nobuo 
Published: July 2007

AbstractIt is known that the bit error rate is deteriorated if there exist echoes on the transmission line. This paper presents a theoretical analysis on influences of an echo on the bit error rate in the optical DPSK communication system. In general, there exists a floor in the bit error rate due to the phase fluctuation of the laser light, which is not reduced by increasing the received optical power. It is shown that the floor value increases with the increase of the amplitude ratio of the echo to the principal wave, as well as the increase of the delay time. It also is shown that the effect of the echo is more remarkable when the bit rate is higher and the spectral linewidth of the laser light is narrower.Finally, the bit error rate is calculated as a function of the received optical power and the power penalty is evaluated. The relation between the bit error rate for which the effect of the echo cannot be ignored and the spectral linewidth is discussed. The features of this paper are that the echo with a small delay time, which has some correlation to the principal wave, can be analyzed.