Kenji OHYA Hiroyuki EGUCHI Masashi HAYAKAWA Yoshihito TANAKA
An analogue equipment is developed and described, which can automatically identify and track the magnetospheric whistler signal so that we can measure the amplitude ratio and phase difference between two horizontal magnetic field components of each whistler over a wide frequency range (6 to 3 kHz) and then we can study the ionospheric transmission characteristics of whistlers.
Kiyoshi TOKO Kenshi HAYASHI Kaoru YAMAFUJI
Spatio-temporal patterns of electric potential produced by a root of azuki bean were investigated. It was found that the electric potential of a root shows a banding pattern surrounding the root and also a spontaneous oscillation. This electro-magnetic circumstance has a relation to its growth.
A method of quick displaying documents stored in electrical filing systems is discussed. The index codes generated automatically when the pictures of an original page are stored, can be decoded to full-page-size rough pictures on the CRT display. The pages are reconstructed at a maximum speed of nearly 20 pages per second. This method makes it possible to quick look over the pages in the image-coded document filing system.
Shuichi FUJITA Takashi MIZUTANI
A new gate current model for the AlGaAs/GaAs heterostructure MISFETs is proposed. This model is derived by taking account of the relationship between the surface potential at the hetero-interface and the gate voltage. The new gate current model is shown to be suitable for analyzing logic circuits with heterostructure MISFETs.
Hitoshi SHIMIZU Yosuke SEKI Tadashi KIMURA Ken-ichi NODA
Feed back control approach for stabilization phase modulator index of PZT phase modulator in all-fiber optic gyroscope is described. Dual core fiber interferometric sensor is applied to detect phase modulating index of PZT cylinder. Fluctuation of modulator versus temperature variation can be approximately eliminated 15 dB by this method.
Osami ISHIDA Yoji ISOTA Moriyasu MIYAZAKI Fumio TAKEDA Norio TAKEUCHI
This letter describes a novel coupled-transmission-line directional coupler using an asymmetrical suspended stripline with unequal conducting strips on both sides of a dielectric substrate. The directional coupler has a rang of coupling values from 5 to 9 dB which is difficult to be realized by a conventional symmetrical suspended stripline coupler.
Hisao KAWASAKI Ichirou INAMI Atsushi TANAKA Hirokuni TOKUDA Mitsugu HIGASHIURA Shigekazu HORI Kiyoho KAMEI
0.25-µm gate low-noise high electron mobility transistors (HEMTs) have been developed, using epitaxial wafers grown by metal-organic-chemical vapour deposition (MOCVD) technique. Minimum noise figures of 0.75 dB and 1.2 dB with associated gains of 11.1 dB and 7.9 dB are obtained at 12 GHz and 18 GHz, respectively, at room temperature. These are the lowest noise figures yet reported for low-noise HEMTs fabricated on MOCVD epitaxial wafers.
Shigeyuki AKIBA Masashi USAMI Katsuyuki UTAKA
The corrugated waveguide parameters and the threshold current densities of the TE and TM modes in InGaAsP/InP λ/4-shifted DFB lasers with non-reflective ends were calculated and the TE/TM ratio over 30 dB was expected. The experimental TE/TM ratios of about 35 dB in a directly modulated condition were shown.
Hitoshi YANAGIURA Hideo KOBAYASHI Junichi TAKAGI Nobuo TOMITA
This letter proposes a cylindrical accommodation block consisting of a number of plastic sheets placed radially. The basic structural design of the block has been made, and it is found that more than 1000-fiber splices, i.e. mass-splices of 200 fiber ribbons can be accommodated with the same size as the existing metallic cable joints.
Masaaki MATSUURA Tadatoshi TANIFUJI Yoshikazu YAMAMOTO
A 1.3 µm edge-emitting LED is used to launch an average optical power of 13.7 dBm into single-mode fibers. This permits analog video signal transmission over a distance of 42 km with a loss margin of 5 dB. No degradations of DG, DP, and signal-to-noise ratio have been observed.
Masahiro MURAGUCHI Takatomo ENOKI Kimiyoshi YAMASAKI Kuniki OHWADA
A 20 GHz band monolithic low noise amplifier combining improved SAINT-FET technology and optimized circuit design has been developed. The amplifier has a measured noise figure of less than 3.5 dB with a minimum gain of 4.2 dB over the 18.5 GHz to 20 GHz range. The optimal noise figure is 2.9 dB with a gain of 5.5 dB at 19 GHz. Standard threshold-voltage deviation of the process monitor FRTs is only 70 mV over the entire area of the 2-inch wafer.
Masashi USAMI Shigeyuki AKIBA Katsuyuki UTAKA
The threshold current Ith of a 1.5 µm range InGaAsP/InP λ/4-shifted DFB laser with low-reflectivity ends was theoretically expected to be 10 mA or less. Experimentally, Ith of 14-16 mA at 20 and the sub-mode suppression ratio of about 35 dB or more in the temperature range of 10-70 were obtained.
Masayoshi KOSHINO Teruo KUROKAWA Yasuo EBATA Motoyoshi TAKASE
The relation between driving current and active again drift in 600 MHz band 2-port SAW resonators on quartz substrate is clarified and the threshold level causing the metal-migration is grasped. A practical method for measuring the driving current is proposed.
Makoto MIZUKAMI Shuichi TAKANAMI
Mechanical interaction in a multi-actuator is suppressed by utilizing a trapezoidal driving current. Fundamental performance of this method is examined experimentally and analytically.
A general and rigorous theory is developed to analyse electromagnetic fields in a domain where a set of parallel plates of conductor of arbitrary shape and of finite dimensions are presented. Based on the theory, a numerical method is also given, which is very useful in solving various practical problems.
Yoshiki YAMAUCHI Tadao ISHIBASHI
The effects of current gain and emitter resistance on the switching performance of ECL gates with GaAs/AlGaAs HBTs are analyzed by circuit simulation. A minimum current gain of 10 and a maximum emitter resistance of less than one fifth of the load resistance were found to be necessary for stable ECL inverter operation.
Ryo DANG Toshiaki KOJIMA Yutaka AKIYAMA Mitsutoshi NAKAMURA
A new threshold voltage formula is derived for a U-shaped gate MOSFET where the gate oxide becomes thicker at both channel ends. It is found that when charge-sharing effect due to source/drain-junctions is not accounted for, threshold voltage increases with decreasing channel length, exhibiting an inverse short-channel effect (ISCE). When charge-sharing effect is taken into account, the ISCE reduces remarkably, resulting in a flat threshold voltage characteristic over a wide range of channel lengths. Computer simulations using a two-dimensional device simulator show a good agreement with these analytical findings.
An analytical estimation of the date replacement method for optical disk media is discussed. A modified Gilbert model is introduced to describe the bit-error occurrence in the reproduction process. This model deduces the defect-relief probability required to estimate the efficiency of a date replacement method.
HASP, a model of Human Associative Processor, has been proposed in a previous paper. Among other associative memory models hitherto proposed, HASP is unique in its multiple match resolution. By this function several items associated with one particular key can be retrieved one by one, and set-theoretically defined multiple key search operations can be performed. However, there was a problem in the performance of HASP. It was the occurance of unknown patterns in a recollection sequence of multiply matched items. It would become a serious defect in appling HASP to such a task as serial association, in which an output became a key input for the next association. In this paper, the origin of the problem is identified and HASP is improved not to produce unknown patterns. The idea is to weaken the competitive powers of the unknown patterns by modifying the strength of inhibitory recurrent paths. A series of simulation studies has been carried out and it is confirmed that the improved HASP can perform multiple key search operations without being contaminated by unknown patterns. Several psychological implications of the performance of HASP are also discussed.
A new transform of trinary vectors, called pseudo-Hadamard transform, is introduced. This transform is a one-to-one mapping in a trinary vector space and very similar to the Hadamard transform. To define the pseudo-Hadamard transform, the Good's formula for the fast Hadamard transform HN of N(=2n) dimension HN=TnTn1T1 is used, where the transform Ti(i=1,2,,n) consists of N additions and subtractions. The pseudo-Hadamard transform is defined by replacing the additions and the subtractions with kinds of trinary operations. This transform preserves some properties of the Hadamard transform and is also very easy to perform. As applications of the pseudo-Hadamard transform, examples of binary image processing are presented.