Shuichi FUJITA Makoto HIRANO Koichi MAEZAWA Takashi MIZUTANI
A high-speed potential of an n+-Ge gate AlGaAs/GaAs MISFET has been confirmed by a ring oscillator and a frequency divider performances. The circuit was based on SCFL with 1.0 µm gate-length MISFET's. The delay time was 42.4 ps with a power dissipation of 8.9 mW/gate. A maximum toggle frequency of 11.3 GHz with a power dissipation of 219 mW per T-F/F has been achieved at room temperature.
Masanobu OHHATA Tohru TAKADA Masayuki INO Masao IDA
A novel level shift circuit for Low Power Source Coupled FET Logic (LSCFL) is proposed that effectively lowers the power supply voltage. Master-slave T-type flip-flops (T-FFs) with reset function using a three level series gate are designed employing the new level shift circuit, and fabricated using the BP-SAINT process. It is demonstrated that this advanced T-FF operates with a power supply voltage of -1.8 V, which is 30% less voltage than the conventional LSCFL.
For clarifying theoretically the behaviour of GaAs/Al1-mGamAs heterojunction-CCD, one dimensional analysis of the channel potential is done, and the heterojunction-CCD charge-transfer process between two transfer-electrodes is represented by analytical method.
Akira MATSUZAWA Yasuto NAKATSUGI Akihiro KANDA Haruyasu YAMADA
In order to realize highly accurate analog to digital conversion for EDTV, HDTV, and video-camera with low power consumption, a monolithic video-rate 8 bit parallel A/D converter has been developed using high-accuracy bipolar transistors with trench isolation. The A/D converter can digitize wide band video signals up to 10 MHz with high signal to nose ratio (45 dB at 10 MHz input) at high conversion rate of 40 MHz. Notwithstanding it contains 7000 bipolar transistors, it consumes only 250 mW and is formed with small chip size (2.7
Akira MATSUZAWA Akihiro KANDA Kazuya KIKUCHI Haruyasu YAMADA
A distribution of offset voltage of transistor pairs having fine pattern emitter down to 0.5 µm wide required for a parallel A/D converter can digitize at more than 200 MHz were measured. Moreover, contributions of transistor parameters to offset voltage and a realization of the ultra-high speed A/D converter were discussed. As the result, it was shown that the main transistor parameter contributes to the offset voltages is a fluctuation of a current gain, and a contribution of a emitter contact resistance was not so large. And the realization of 6 bit, 1 GHz or 8 bit, 750 MHz A/D converter was obtained.
Naoyuki SHIGYO Koichi SATO Koichi KATO Tetsunori WADA
This letter describes the newly developed device simulator TRITON. Emphasis is on the fully automatic triangle mesh generation, based on the string data which represent the device shape. Poisson's and current continuity equations for electrons and holes are discretized by the control volume method.
Shinya YOSHIDA Kazunori OHNISHI Kenji KAWANISHI Masayuki NAMIKI
A few experimental reports are available for designing of MOS hall devices. We are experimentally studied several magnetic characteristics of the device which has indivisual 7 segment hall voltage probes. As a conclusion, we obtained most appropriate designing condition for the MOS hall device.
Yasuhiro TANAKA Toshihisa HONMA Ikuo KAJI
Boundary-element solutions of an unsteady-state convective diffusion equation are investigated using a mixed boundary-element method with both constant and linear elements. Transient numerical solutions at each discrete time are compared with exact solutions so that the dependence of their relative errors on time and space are demonstrated. It is shown that the present method is applicable to an electromagnetic field analysis governed by the partial differential equation of convective-diffusion type as in a steady state problem.
Kuniyuki MOTOJIMA Toru KOBAYASHI Shogo KOZAKI
Electromagnetic scattering by four perfectly conducting rectangular cylinders is analyzed by Point Matching Method. The numerical results are in full agreement with the results for the well known integral solution method. And this letter give not only the field calculated around four cylinders but also model experiments using a line source at 9.6 GHz. The numerical results are in nearly good agreement with the experimental results.
Nobuo KUWABARA Tsuyoshi IDEGUCHI
An analytic expression of electromagnetic near field emitterd by a single current flow along a straight wire is derived to obtain the radiated EMI limit from the telecommunication lines connected to the equipment. The validity of the theory is tested in the experiment. Calculations show that the conversion factor between the electric field strength and the terminal voltage is not significantly changed by the wire length. A maximum conversion factor of about -30 dB in the frequency range of 0.1 -30 MHz is obtained.
Kentaro NAKAMURA Makoto ANDO Naohisa GOTO
A full-wave analysis of antennas with polarization grids is performed. Radiation patterns of antennas for two types of grids (straight strip and curved strip) are presented, where effects of the grid position and the grid paramenters are discussed.
Hiroshi NISHIWAKI Hiroyuki ARAI Naohisa GOTO
This letter presents an approximate analysis for coupling coefficients of a multi-slotted directional coupler to diagnose propagating modes in an output waveguide of a gyrotron. The coupling coefficients are calculated approximately and verified by a rigorous analysis.
Toshiyuki TANAKA Kiyotoshi YASUMOTO
A two-dimensional radiation by a relativistic sheet electron beam passing over a corrugated conducting surface is investigated. The leakage coeffcient and phase change of space-charge waves due to the radiation is calculated using a perturbation approach based on the multiple scales.
Makoto MATSUNAGA Yoshitada IYAMA Kazuhiko NAKAHARA Fumio TAKEDA
This letter describes a high power monolithic GaAs FET transmit-receive switch (TR switch) with two FETs. Both FETs operate in the same states, low impedance state in transmitting and high in receiving, so rf voltage imposed on FET is low both in transmitting and receiving. The developed TR switch can handle more than 12 W peak power at X-band frequencies.
Masahiro MURAGUCHI Kuniki OHWADA
A Ku-band monolithic voltage controlled oscillator (VCO) has been developed. All the circuit elements for the VCO, i.e., an FET, a control diode, an output matching circuit, a stabilizer, and associated circuitary were integrated on a single chip. This VCO is characterized by using a unique stabilizer. The VCO with its stabilizer has shown stable oscillations across a tuning bandwidth covering 12.30 to 12.80 GHz with control voltage of
Hiroshi NAKAMOTO Masaaki MATSUURA Fumihiko ITO Tadatoshi TANIFUJI
Buried heterostructure waveguides with high coupling efficiency for dual shaped core fiber with zero dispersion at 1.55 µm are described. Calculations reveal that the mode mismatch loss of 0.35 dB with mode confinement coefficient of 0.6 can been achieved for dual shaped core single-mode fibers. While, for conventional single-mode fibers, mode mismatch loss becomes large.
Hiroaki TAKEUCHI Hiroshi YASAKA Yuzou YOSHIKUNI Kunishige OE
We report a low loss strip loaded single mode waveguide with a GaAs/Al0.3Ga0.7As double heterostructure. The propagation loss is derived to be 1.3 dB/cm for 1.3µm single mode propagation from Fabry-Perot resonances of a waveguide with good cleaved facets using DFB laser.
Fumihiko ITO Tadatoshi TANIFUJI
A design principle of total reflection type optical switches with broad wavelength bandwidth using the plasma dispersion effect in GaAs is described. Wavelength dependent excess loss due to Goos-Hanchen shift in wavelength region from 1.3µm to 1.55 µm is reduced to within 0.1 dB with waveguide cross angle of 5
Kotaro SUGITA Yasuyuki SUGIYAMA Isamu KATO Koki SATO
Optical waveguide polarizers are realized by three dimensional polymer thin film waveguides with a-Si: H film clad. It has a low index buffer layer between the waveguide and a-Si: H film clad. It is experimentally found that a high extinction ratio for either TE or TM mode pass polarizer can be obtained by changing the hickness of the a-Si: H film clad.
Masaaki DOI Minoru KAWANO Isamu KATO Koki SATO
A new fabrication method of a star coupler has been described. It is fabricated by stacking polymer films and then sticking them by a heat press. Using this method, the star coupler can be produced very easily and has square core cross sections. The 5-port multimode star coupler made on an experimental basis has an output power variation of 0.9 dB and an insertion loss of 3 dB.
This letter describes structural design of a ribbon-to-single-fiber fanout connector. Considering bending strain and bending loss applied to the fibers for fanout, the relationship between the number fibers in the ribbon and the minimum length for fanout has been clarified.
Akira IINO Mikio OGAI Kunihiro MATSUBARA
Sodium and potassium contained in natural silica tubes have been found to migrate into the central part of germania doped silica fiber during drawing process after secondary ion mass spectrometry (SIMS) measurements. Migrated such impurities caused the structural change of germania doped silica glass, which raised hydrogen induced loss increases in infrared wavelength region.
Akira IINO Mikio OGAI Kunihiro MATSUBARA
A few ppm of sodium and potassium contained in natural silica tube has been found to be removed during the deposition process in MCVD fiber, while remaining such alkalies in over-jacketed natural silica tube was pointed out to migrate into the germania doped core part during drawing process and to deteriorate resistivity against hydrogen.
Tatsuya FUCHIGAMI Yutaka YOKOO Katsunori UGAWA Masaaki KAWASE
Optical loss increase of SP-optical fiber cable at low temperature was investigated theoretically and experimentally. Estimation formula was presented for the relation between excess fiber length and optical loss increase. It was clarified that excess fiber ratio normalized by pipe radius of less than 0.005 was required to suppress optical loss increase at
A new reinforcement machine using induction heating has been developed for heat-shrinkable-sleeve reinforcement method. Through the proper thermal design of the heating system, the reinforcement of a single-spliced fiber was completed in 30s with good performance by supplying 200 W
Yasuyuki KATO Toshio OOYANAGI Akihiko ISHIKURA Mitsuru MIYAUCHI
A new stuffing-pulling fusion technique for the mass fusion splicing of single-mode fibers is presented, where the fiber spliced-region is pulled after the fiber end faces are fused and stuffed to each other. The characteristic feature of this technique is that the stuffing and pulling strokes are varied, based on the observation of fiber end face gaps for every splice. This technique can reduce splice loss to a half in comparison with the conventional method.
A new method fot the refractive index distribution measurement using a set of single-mode and multimode optical fibers is investigated experimentally. It is confirmed that the optical multiple reflection is neglected, and this leads the accurate measurement with high stability and easy handling.
A Rayleigh backscattered signal over a 64 km single-mode fiber has been successfully observed by a long-range OTDR utilizing a 1.5µm LD and an InGaAs/InP APD cooled to 0
Tanroku MIYOSHI Hiroshi KIMURA Matsuto OGAWA
As a general approach to analyse the field effects on a quantum well with arbitrary potential distribution, a method based upon finite element is presented. The field dependence of the resonant width and the effective energy gap is analysed for quantum wells with potential deformation around the center of wells.
Koichi WAKITA Masashi NAKAO Yuichi KAWAMURA Hajime ASAHI
A large on/off ratio with low drive voltage optical modulation is realized by using waveguide InGaAs/InAlAs multiple quantum well (MQW) structures grown by molecular beam epitaxy (MBE). These waveguide MQW optical modulators have a modulation on/off ratio of 90:1 (19.5 dB) at a driving voltage as low as 2.5 V.
Yoshihisa SAKAI Shigeki AISAWA Ken-ichi HAYASHI Kazuo ARAI Yoshio IDA
The influence of 1/f noise in FM noise on the spectral linewidth of semiconductor lasers in a normal operation has been investigated. The linewidth calculated from the FM noise spectrum considering the 1/f noise agrees with that obtained from the delayed self-heterodyne method.
Ken-ichi HAYASHI Koichi IIYAMA Yoshio IDA Kazuo ARAI
A novel and simple measuring method for locking bandwidths of injection-locked semiconductor lasers is proposed. The measuring system based on this method can visualize the overall locking bandwidth and quickly measure the boundaries. Some experimental results are also presented.
Hajime SHOJI Yasuhiko ARAKAWA Yoichi FUJII
Bistable operation in inhomogeneously excited semiconductor lasers is discussed theoretically considering gain dispersion effects. The results indicate a significant dependence of bistable properties on lasing wavelength when the wavelength is fixed by some selection mechanisms such as distributed feedback structures.
Toshiyuki KANO Hiroshi TANIGUCHI Hiroshi SAITO
A copper vapor laser performance by using a metal-vapor-complex reaction (Cu
Shinzo MUTO Haruki UCHIDA Toshimasa TAKAUCHI
In this letter, the thin film dye laser with DFB oscillator, amplifier and mode filter has been studied. The system is simply constructed on the anisotropic crystal prism such as KDP and operates as a compact tunable solid dye laser.
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.
Tadashi KATO Ryoichi ARAI Shuichi TAKANAMI
A modified cosine equalization effective for equalizing both amplitude and phase has been developed with a simple circuit. It slims asymmetrical read-back waveforms in digital magnetic recording devices more effectively than without phase equalization.
Kenji MOCHIZUKI Isamu SATO Ryoichi ARAI
This letter describes a highly sensitive method for detecting contact between a head slider and disk medium. It is shown to provide 10 dB or greater improvement in the signal to noise ratio (SNR) from the small piezoelectric transducer attached to the head slider by using a new frequency mixer circuit.
Manabu YAMAMOTO Hiroshi NAKANISHI Shigeji HARA
The relationship between playback laser power and bit error increase caused by continuous playback is considered. In the Te system write-once media, bit errors increase gradually due to the phase chage of media. Playback laser power should be designed so as media temperature is not overly increased. In TbFe system magneto-optical recording media, bit errors don't increase when playback laser power is lower than threshold recording power.
Hiroo UKITA Yoshitada KATAGIRI
The light output of a injection laser in a short (several µm) external cavity has been investigated both experimentally and theoretically. The amplitude modulation ratio of the light output signal reaches maximum where the drive current is below the threshold lasing current. An antireflection coated (ARC) laser diode is useful in increasing the light signal.
This letter proposes an effective media menagement method for optical mass storage systems. In this method, the system, instead of the connecting host computer, manages the relathionship between media and the medium cells by itself. This frees the host computer from media management. As a result, it can access the data blocks on these media with ease similar to accessing one medium.
Osamu SHIMOMURA Kazunobu OHHASHI Yoshitaka SASAZAWA Kazumasa IDE Kisei KOMORI
In the KDP solution Fe3
Yukihiro KIYOTA Kouji NUMADA Isamu KATO
We have fabricated SiN films with stoichiometric composition by double tubed coaxial line type microwave plasm chemical vapor deposition and have discussed the effects of the microwave power on the film qualities.
Effect of annealing on electrical conductivity of sintered silicon carbide containing boron carbide and carbon was investigated. The silicon carbide was sintered at the temperature range of 1650
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.
Terutaka TAMAI Mitsuo KOMINAMI
By applying the ellipsometric analysis, the relationships between the growth of contaminant film on contact surface and contamination time were clarified with respect to the contact resistance and formation of the film. Contamination parameters for reaction formulas which are concerned with growth laws of contamination films for sulfuration of Ag and for oxidation of Cu were deduced.
Takao NAGATOMO Mitsuyuki MITSUI Kazuhiro MATSUTANI Osamu OMOTO
A recondary battery utilizing poly(3-methylthiophene) film as a cathode-active meterial in an electrolyte of LiBE4/organic solvent with Al anode was studied. Experimental energy density of 326 Wh/kg (at a doping level of 38%, discharge capacity of 97.3 Ah/kg, and a mean discharging voltage of 3.3 V) was obtained on the weight of the film. The coulombic efficiency was above 96% even after 1200 cycles at a doping level of 9%. The discharge characteristics are described in relation to the surface morphology of the films.
Sumihisa HASHIGUCHI Naofumi HOSHI
The threshold sensitivity for the contact-free detection is improved by utilizing a dual carrier configuration. Reduction of the ambient temperature fluctuation down to 0.1 degree rms per 1 Hz. bandwidth is enough for the detection of the relative resistance fluctuation down to one part in 1012.
Teizo AIDA Satoru HAYASAKI Seizi MIZUTANI Yutaka SAKAUE Hideo KUGISAWA
The measuring error in the measurement of the glossiness of curved surfaces was significantly reduced by two techniques; change of the setting of the CCD line sensor and scanning of specimens.
Koji YAMASHITA Osamu FUJIWARA Kazuo KATOH Takashi AZAKAMI
This letter presents a method for estimating the discontact rate by the pantograph noise current using a statistical test. This method requires no apriori information on the current collection system used in the previous methods. The experiment is performed to verify the validity of the above method.
Takeshi KONDOH Osamu FUJIWARA Kazuo KATOH Takashi AZAKAMI
This letter presents a method for visualizing the 2-dimensional distribution of electrostatic charge, which is based on the principle of the X-ray CT. For confirming the possibility of this method, the focusing images of the simple model are also demonstrated by a computer computation.
A method of domain attribute identification for automated document storage devices is discussed. Only run-length parameters are used to identify the attribute of a domain on a page. This method makes it possible to obtain indexes of every page automatically and to reconstruct an abbreviated picture quickly in the image-coded document filing system.
Masahiro TOKI Shinichi HATTORI
COMOS Overtone Crystal Oscillator Circuit can be obtained, by adjusting the value of the gate-drain external resistor. A method of adjusting the value of the extermal resistor is presented.
Tatsuki WATANABE Masayuki MATSUMOTO Tekken LI
In most of the voltage-mode CMOS-multiple-valued-logic circuits published so far, distinct voltage levels are used for the logic values and the logical operations are carried out by binary circuits through converting once multiple-valued imputs to binary signals. In this case, encoder circuits are employed for the multiple-valued outputs. Such voltage-mode circuits are not always competitive with binary circuits except for the reduced number of pins for IC realization. In this letter, new CMOS logical-sum (Max) and logical-product (Min) circuits which can perform directly multiple-valued-logic operations without converting multiple-valued inputs to binary signals are presented. As the proposed circuits have the same property of low-power dissipation as usual CMOS inverters, they are suited for binary circuit use as well. In two-input case, each of the logical-sum and logical-product circuits is composed of a pair of PMOS and NMOS transistors and, except for the number of inputs and the circuit-function, the circuit configuration is the same as that introduced by Sugano, Tarui and Asada. The transient characteristics of the proposed circuits obtained by SPICE-2 simulations are shown. In this letter, logical values 0, 1, 2, and 3 are represented by voltage levels 0 V, 2 V, 4 V and 6 V respectively.
Keiichi UCHIMURA Junji MICHIDA Shinji NOZU Teizo AIDA Hiroshi ECHIGO Tasuku TAKAGI
This letter deals with a newly developed automatic system, which measures the rate of malfunction of digital circuits owing to noise induced by breaking electric contacts. In this system, a personal computer is used for the detection and the count of the malfunction in the digital circuit. Its experimental results are reported here.
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.
Hiroshi KONDO Yoshiaki NAGANO Kazunobu KANDA
We derive the relationship between the Fourier transform magnitude and the phase of the original signal from the degraded one. The phase of the original signal can then be specified uniquely from the Fourier transform magnitudes of the relevant signals and the phase of the degraded signal and the system transfer function.
Yukiyoshi KAMIO Seiichi SAMPEI Hideichi SASAOKA Mituo YOKOYAMA
In this paper, a newly developed fading simulator (FS) is presented. This FS can produce the same fading situation repeatedly and the DSP (Digital Signal Processor) is used for its implementation. The structure and performance of the FS are also presented.
Noboru ISHIHARA Hiroyuki KIKUCHI Mamoru OHARA
A Monolithic amplifier IC with small phase deviation applying parallel feed back technique was developed by using high speed Si bipolar process technology. This IC achieves a phase deviation of 1.8
Tomohiko UYEMATSU Osamu HIROTA Kohichi SAKANIWA
For optical digital communications with energy loss, it is shown that there is a state which achieves much superior bit error rate than the Glauber coherent state even if the signal to quantum noise ratio is the same. Moreover, the lower bound for bit error rate is obtained.
Coplanar silicon-coupled bridge type Josephson junctions with recessed niobium electrode structure were fabricated with a new planarization process and Josephson current was observed for the device with an electrode spacing of 50 nm. This device structure has potential to a three-terminal supercouductive device controlled by an insulated gate.
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.
A Burmese English word Processing System (BEPS) has been designed as a prototype system for development on a pernonal computer. BEPS can process visually natural output letters and has advanced capabilities comparable to those of modern English word processing systems.
This paper reviews the experimental data that have been reported since 1980 on long-wavelength (λ
Zukowski's theorem on a monotone onvergence of the Waveform Relaxation (WR) is slightly generalized. The sequence of iterated waveforms in the WR method is proven to converge monotonically for a system where the time derivative of variables reduces to a quase-monotone increasing function by a liner transformation of the variables. This result is then applied to a class of MOS digital circuits, and a sufficient condition on the topology of the circuit and input waveforms is derived such that the sequence of iterated waveforms in the WR method applied to the circuit converges monotonically.
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.
One of the motives of recent studies for designing discrete-time impedances by using the Switched-Capacitor (SC) technology, is to simulate general impedances such as FDNR, Super-L and so on. Authors have previously proposed the
Nobuyoshi KIKUMA Kazuaki TAKAO
The adaptive array under the principle of directionally constrained minimization of power (DCMP) operates to minimize the output power under the constraint to maintain the specified response to the direction of the desired signal. This constraint depends on the a priori knowledge of the relation of the output at each element of the array with respect to the desired signal. If this setting contains some error, the desired signal will be taken for the unwanted one and hence become a target of suppression. To prevent this malfunction, we introduce a modified system of DCMP, which is named the tamed adaptive array, and demonstrate its effectiveness against such imperfect constraint. We consider two examples that cause such effects, i.e., the mutual coupling and random input errors, and numerical results show that the tamed system is robust against those influences.