ZHAO Qiangfu Masayuki KAWAMATA Tatsuo HIGUCHI
This paper studies the design problem of causal, recursive and separable denominator (CRSD) 3-D state-space digital filters. First, a balanced approximation method and a synthesis method of optimal realizations of CRSD 3-D digital filters are proposed by introducing the concept of characteristic filters. Then, a simple equivalent relation between balanced realizations and optimal realizations of CRSD 3-D digital filters is revealed. Using this relation and the balanced approximation method proposed, this paper proposes a spatial-domain direct design method of CRSD 3-D digital filters. This direct design method can perform approximation and synthesis of CRSD 3-D digital filters simultaneously. Further, it can result in stable state-space digital filters which are nealy optimal with respect to roundoff noise, and free of overflow oscillations. Effciency of direct design method is shown by a numerical example.
Fretting motion in static contacs of mated metals can lead to a remarkable increase of their contact resistance. When such fretted contacts are in the state of being totally cut off from any electric source, a millivolt-order contact voltage is often induced in them. An outline of such voltage generation was reported in the former letter. In this phenomenon, the most interesting fact is that the emerging voltage has a particular polarity, when dissimilar metals are meted as contacts. This letter deals with continued experimental studies concerning such contacts of mated dissimilar metals and physical discussions on the emerging voltage with a particular polarity.
Masayuki KAWAMATA Tatsuo HIGUCHI
In order to suppress constant input limit cycles in 2-D separable denominator digital filters, bias cancel realizations are proposed by modifying 2-D separable denominator digital filters free of zero imput limit cycles.
Shinzo MUTO Akitoshi ANDO Osamu YODA Takayuki HANAWA Hirosi ITO
The tuning property of the fiber sheet type dye laser has been studied. When the array of the active fibers doped with a laser dye in a plastic core is pumped by a pulsed N2 laser, the fiber dye laser emission with narrow spectrum is obtained in wide wavelength region.
Fumio UENO Takahiro INOUE Yuji SHIRAI Mamoru SASAKI
A maximum and a minimum circuits with multiple inputs are proposed. The operating speeds of these circuits are independent of the number of the inputs. Since the proposed circuits consist of only NMOS transistors, they can be implemented in semi-custom IC forms. A potential application of these circuits is a real-time fuzzy controller.
On the basis of a nonnegative and a monotonic property of the solution of a special class of differential equations, the transient responses of a class of MOS digital circuits are proven to have a monotone sensitivity with respect to some transistor parameters.
Usually periodic behaviour can be hardly seen in quasi-periodic oscillation, r1 cos ω1tr2 cos ω2t, when ω1/ω2 is not simple rational number, however we succeed in finding out new type oscillatory behaviour of it in the point at which the amplitude is extremum.
Yoshio NAKATANI Yakichi KANATA
This paper describes a basic theory and the experimental results of a RCC (Ringing Choke Converter) in which a MOS FET is used as the switching element and the driving circuit has been modified to improve the efficiency and the characteristics under no-load conditions.
This paper presents a periodic sampling queueing model with (active) processing/interruption phases, Poisson arrivals and a generalized processing probability in accordance with the number of customers at sampling points. The generating functions of the number of customers in a system immediately following sampling points are obtained from the existing results of a generalized periodic sampling model. Using these functions, generating functions of the number of customers at arbitrary points are formulated for active processing and interruption phases. Performance measures such as average customers in a system and average waiting time are derived. Formulas for a single processor model are tailored for a specific application to a common channel signaling system shared between call signals and database information signals. Numerical examples for this system are presented as a guide for the traffic design regarding the ratios of active/interruption phaese and sampling preiod/average processing time.
Hitherto obtained results on the qualitative behaviors of nonlinear dynamical systems are applied to MOS digital circuits, and a class of these circuits is shown to have some monotonic properties such as nonnegativity-preservation, isotonicity, and monotone convergence to a dc solution.
Minoru YAMADA Keiichi OMI Yasumasa NASHIDA Masao GAMO
A theoretical prediction that the lasing gain must increase by breaking the electrically neutral condition in the active layer is given. A possible structure to give a very low threshold current less than 1 mA was discussed.
This letter reports the optical Waveguide of KDP-DKDP mixed crystal grown on the {101} plane of DKDP crystal by the LPE technique. The propagation loss of the waveguide is 0.5 dB/cm for the TM modes.
Terunori MORI Takeshi SATO Yukifumi SHIGEMATSU Masahiro YAMADA Harehiko NOMURA
We found that the ultrasonic irradiation induced significant but reversible changes in the excitation level of neurones in the central ganglia of a marine molluse, Aplysia. The experiments indicate the potential applicability of ultrasonics as a means of non-invasive stimulation for a selected area of the central nervous system.
Yasuo HIROSE Takemitsu ABE Hiromichi KOMAI Yasuo TSUZUKI
This paper describes a highly sensitive optical fibre interferometric vibration sensing system. The system is capable of measuring three dimensionally high frequency mechanical vibration amplitudes down to the order of 0.1-0.01 Å at frequencies ranging from 10 kHz up to 30 MHz. The system is stabilized by a unique feedback compensation scheme against phase variations appearing in two interfering light beams due to various disturbances. Use of this scheme has hence realized highly sensitive semiautomatic scanning measurements.
Noise behavior of the injection locked IMPATT amplifier with antiphase self-injection is investigated experimentally. The noise performance of this amplifier, which has wider locking range and faster phase response than ordinary one's, is not at all inferior to that of ordinary one's.
Shigenobu SHINOHARA Edson Toshiaki SHIMIZU Hirofumi YOSHIDA Masao SUMI
The self-mixing type laser Doppler velocimter gives a simple method of directional velocimetry. The beat signal comprises the fundamental Doppler frequency as well as its harmonics, so that the waveform is like a sawtooth in which the sign of inclination reverses as the target changes the direction of its movement.
This paper investigates convergence properties of a circuit simulation technique called Waveform Relaxation (WR). A general formulation of a family of WR algorithms called a generalized WR is introduced. This formulation reduces to some hitherto introduced WR algorithms in particular cases. The following two sufficient conditions for the generalized WR method to converge locally are given: ) the capacitance matrix of the circuit is block strictly diagonally dominant and a time-steplength is sufficiently small; ) the conductance matrix of the circuit has the same property and a time-steplength is sufficiently large.
The single fundamental transverse mode condition, both in three-layer DH, and asymmetrical five-layer separate confinement heterostructure (SCH) laser diodes operating at 1.55 µm wavelength, has been investigated based on the effective refractive index. The simple derived formula can be applied to obtain the effective refractive index of the dominant mode in DFB laser diodes to determine the corrugation period corresponding to the designed wavelength.
The effects of external noise on lifetime of metastable oscillation mode observed in forced van der Pol oscillator are investigated to clarify the origin of destablization of the modes. The noise is found to suppress the stability of the mode when the noise is intense enough compared with the fluctuation inherent to the oscillator.
Shigeru YANAGI Masafumi SASAKI
Determination of spare quantity assuming a general failure distribution is discussed. A new method is presented which is an extension of a usual normal approximation method. The original method is essentially a Normal distribution approximation" to a Poisson process of failure occurrence. On the other hand, the new method assumes a general failure distribution. The mean and the variance of the number of failures within for a given period of time are necessary for determining the spare quantity. The mean is obtained in a simple form. The variance is give as a solution of an integral equation. The solution of this equation for a general case is obtained by applying a discrete approximation technique. Some numerical examples are provided to discuss the difference between when assuming a general failure distribution and when assuming the exponential failure distribution.