Patents Assigned to Nippon Telegraph and Telephone Public Corporation
  • Patent number: 7187769
    Abstract: In the evaluation of the randomness of an S-box, measures of resistance to higher order cryptanalysis, interpolation cryptanalysis, partitioning cryptanalysis and differential-linear cryptanalysis and necessary conditions for those measures to have resistance to each cryptanalysis are set, then for functions as candidates for the S-box, it is evaluated whether one or all of the conditions are satisfied, and those of the candidate functions for which one or all of the conditions are satisfied are selected as required. It is also possible to further evaluate the resistance of such selected functions to at least one of differential cryptanalysis and linear cryptanalysis and select those of the candidate functions which are resistant to at least one of the cryptanalyses as required.
    Type: Grant
    Filed: June 1, 1999
    Date of Patent: March 6, 2007
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventors: Shiho Moriai, Kazumaro Aoki, Masayuki Kanda, Youichi Takashima, Kazuo Ohta
  • Patent number: 7180341
    Abstract: A feedback path (307) is formed between an output (310c) of a fixed divider (305) and a control terminal (310b) of an inverting/noninverting unit (304). A connection device (306) is arranged on the feedback path (307). The feedback path (307) is connected/disconnected according to the level of the control signal M from outside, thereby switching the number of divisions. The delay time of the signal given to the input terminal (310a) of the inverting/noninverting unit (304) to pass through the feedback path (307) and return to the control terminal (310b) is set greater than the pulse width of the input clock signal. A small pulse input invalidating function is provided in the fixed divider (305). Alternatively, a small pulse output prohibiting function is provided in the inverting/noninverting unit (304).
    Type: Grant
    Filed: May 17, 2004
    Date of Patent: February 20, 2007
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventors: Mitsuru Harada, Akihiro Yamagishi
  • Patent number: 5786105
    Abstract: A solid oxide fuel cell which includes a substrate having therein a plurality of gas supply passages and a plurality of gas return passages. The gas supply passages have inlet ports on a surface of the substrate and the gas return passages have outlet ports on the same surface of the substrate. A header is interposed between the gas supply and gas return passages so that gas enters the header from the gas supply passages and then enters the gas return passages. The flow rate of the gas in the gas supply passages is less than the flow rate of the gas in the gas return passages. A solid electrolyte is formed on a first surface of the substrate, an electrode is formed on the solid electrolyte, and an interconnector is formed on a second surface of the substrate.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: July 28, 1998
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventors: Toshio Matsushima, Daisuke Ikeda, Himeko Kanagawa
  • Patent number: 5661560
    Abstract: In a photomask inspecting method, a photomask is inspected on the basis of the difference between the polarized state of elliptical light produced upon superposition of two linearly polarized light beams having orthogonal polarization directions and passing through two different optical paths and the polarized state of elliptical light produced when two linearly polarized light beams are superposed on each other after a target portion of a photomask is set in the optical path of one of the linearly polarized light beams. A photomask inspecting apparatus is also disclosed.
    Type: Grant
    Filed: May 29, 1996
    Date of Patent: August 26, 1997
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventor: Yoshiharu Ozaki
  • Patent number: 5548401
    Abstract: In a photomask inspecting method, a photomask is inspected on the basis of the difference between the polarized state of elliptical light produced upon superposition of two linearly polarized light beams having orthogonal polarization directions and passing through two different optical paths and the polarized state of elliptical light produced when two linearly polarized light beams are superposed on each other after a target portion of a photomask is set in the optical path of one of the linearly polarized light beams. A photomask inspecting apparatus is also disclosed.
    Type: Grant
    Filed: August 19, 1994
    Date of Patent: August 20, 1996
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventor: Yoshiharu Ozaki
  • Patent number: 5379361
    Abstract: An optical fiber connector for splicing a plurality of optical fibers integrally, including V-groove substrates each comprising V-grooves for setting optical fibers therein. Further, positioning standard surfaces arranged in parallel with a V-groove forming direction are formed in the substrates to enable stacking of the substrates on the basis of the positioning standard surfaces.
    Type: Grant
    Filed: March 25, 1993
    Date of Patent: January 3, 1995
    Assignees: NGK Insulators, Ltd., Nippon Telegraph & Telephone Public Corporation
    Inventors: Koichiro Maekawa, Takashi Ota, Masashi Fukuyama, Shinji Nagasawa
  • Patent number: 5280469
    Abstract: A system for monitoring an ATM cross-connecting apparatus by rewriting a VPI conversion table to various values, inputting a test cell, and examining the test cell after the test cell passes through the ATM cross-connecting apparatus. Entries of a VPI conversion table are accompanied by traffic flags indicating whether or not the corresponding entry is occupied for use for user's signals. First, the traffic flags are examined. Each entry not occupied for user's signals can be freely rewritten. Each entry occupied for user's signals is not rewritten. The examination of the test cell is carried out by comparing the test cell output from the ATM cross-connecting apparatus, with a reference cell which is expected from a normal operation of the ATM cross-connecting apparatus. The virtual path identifier converted in the ATM cross-connecting apparatus and contained in the output test cell, is expected corresponding to the above rewriting operations, and is contained in the reference cell.
    Type: Grant
    Filed: June 18, 1992
    Date of Patent: January 18, 1994
    Assignees: Fujitsu Limited, Nippon Telegraph and Telephone Public Corporation
    Inventors: Ikuo Taniguchi, Kenji Narita, Kenichi Hashimoto
  • Patent number: 5097204
    Abstract: A method and apparatus for testing an integrated electronic device wherein the integrated electronic device to be tested is placed on a sample table. A predetermined position of the integrated electronic device is irradiated with the primary charged beam. A substrate current flowing through a substrate of the integrated electronic device is measured upon radiation of the primary charged beam, and then a potential of the predetermined position irradiated with the primary charged beam is nondestructively measured in accordance with secondary electrons emitted from the predetermined position. A function of the integrated electronic device is evaluated in accordance with the substrate current and the predetermined position potential. The function to be evaluated includes leakage characteristics and a capacitance.
    Type: Grant
    Filed: October 3, 1990
    Date of Patent: March 17, 1992
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventors: Masahiro Yoshizawa, Akira Kikuchi, Kou Wada, Minpei Fujinami, Nobuo Shimazu
  • Patent number: 4980639
    Abstract: A method and apparatus for testing an integrated electronic device wherein the integrated electronic device to be tested is placed on a sample table. A predetermined position of the integrated electronic device is irradiated with the primary charged beam. A substrate current flowing through a substrate of the integrated electronic device is measured upon radiation of the primary charged beam, and then a potential of the predetermined position irradiated with the primary charged beam is nondestructively measured in accordance with secondary electrons emitted from the predetermined position. A function of the integrated electronic device is evaluated in accordance with the substrate current and the predetermined position potential. The function to be evaluated include leakage characteristics and a capacitance.
    Type: Grant
    Filed: March 3, 1988
    Date of Patent: December 25, 1990
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventors: Masahiro Yoshizawa, Akira Kikuchi, Kou Wada, Minpei Fujinami, Nobuo Shimazu
  • Patent number: 4975102
    Abstract: An optical transmission fiber comprising (1) a core of high refractive index composed of SiO.sub.2 -based glass containing at least one of GeO.sub.2, As.sub.2 O.sub.3, Sb.sub.2 O.sub.5, SnO.sub.2, TiO.sub.2, PbO and Bi.sub.2 O.sub.3, (2) a clad of low refractive index composed of SiO.sub.2 -based glass containing at least one of B.sub.2 O.sub.3, F, F/B.sub.2 O.sub.3 and F/P.sub.2 O.sub.5, and (3) an outermost jacket layer composed of SiO.sub.2 and/or SiO.sub.2 -based glass containing at least one of Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2 and HfO.sub.2.
    Type: Grant
    Filed: October 19, 1988
    Date of Patent: December 4, 1990
    Assignees: Nippon Telegraph & Telephone Public Corporation, Sumitomo Electric Industries, Ltd.
    Inventors: Takeo Edahiro, Shiro Kurosaki, Minoru Watanabe
  • Patent number: 4966434
    Abstract: An optical fiber cable comprising a core which comprises at least two filaments stranded, at least one optical fiber stranded around the core and a jacket around the optical fiber, wherein the strand pitch of the filaments of the core is greater than that of the optical fiber, in which the optical fiber contained is free from elongation strain when the cable is stretched.
    Type: Grant
    Filed: August 21, 1984
    Date of Patent: October 30, 1990
    Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph and Telephone Public Corporation
    Inventors: Shinichi Yonechi, Yukinori Ishida, Masaaki Kawase
  • Patent number: 4878933
    Abstract: A pair of V-shaped slot blocks mounted movably on a base in both the X and Y directions and a microscope for observing the opposed state of optical fibers contained on the blocks, are provided in an apparatus for fusion splicing optical fibers. The microscope is mounted movably in the X and Y directions under a base, thereby observing the opposed states of the optical fibers from below.
    Type: Grant
    Filed: December 16, 1986
    Date of Patent: November 7, 1989
    Assignees: Fujikura Ltd., Nippon Telegraph & Telephone Public Corporation
    Inventors: Takeshi Yamada, Yasukuni Osato, Okosu Watanabe, Masao Suzuki, Osamu Kawata, Koushi Ishihara
  • Patent number: 4863554
    Abstract: An apparatus for pulling a single crystal by CZ method or LEC method is improved. To this end, the heater for heating the inside of the furnace is divided at least in the vicinity of the solid-liquid interface into at least two heaters. Using this apparatus, a single crystal with a decreased dislocation density can be obtained.
    Type: Grant
    Filed: February 20, 1987
    Date of Patent: September 5, 1989
    Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph & Telephone Public Corporation
    Inventors: Akihisa Kawasaki, Toshihiro Kotani, Ryusuke Nakai, Shintaro Miyazawa, Keigo Hoshikawa
  • Patent number: 4857001
    Abstract: An electrical connector having contact elements, for mounting a leadless circuit board to a mother board. Each contact element is provided with a projection laterally projecting therefrom which engages with the lower opening edge of a through-hole of the mother board to maintain the connector in contact with the surface of the mother board. Connector apertures are arranged to a zigzag pattern to form first and second rows, and the contact elements are inserted in the apertures of the first and second rows with reversed orientation.
    Type: Grant
    Filed: April 6, 1988
    Date of Patent: August 15, 1989
    Assignees: Nippon Telegraph & Telephone Public Corporation, Nippon Electric Co., Ltd., Japan Aviation Electronics Industry Limited
    Inventors: Kenichi Nakano, Yoshihiro Umezawa, Tetsuro Tokaichi, Yoshiaki Ichimura, Natsuki Kawabe
  • Patent number: 4850022
    Abstract: A speech signal processing system in which the correlation is removed from the sample values of a speech waveform supplied to an inverse-filter for obtaining sample values of a prediction residual waveform, phase-equalizing filter coefficients are determined to have phase-characteristic inverse to that of the prediction residual waveform at each pitch position of the speech waveform, the phase-equalizing filter coefficients are set as filter coefficients of the phase-equalizing filter, and the speech waveform or the prediction residual waveform is passed through the phase-equalizing filter, thereby zero-phasing the prediction residual waveform or the prediction residual waveform component in the speech waveform and concentrating energy around the pitch position.
    Type: Grant
    Filed: October 11, 1988
    Date of Patent: July 18, 1989
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventors: Masaaki Honda, Takehiro Moriya
  • Patent number: 4838916
    Abstract: A single-polarization single-mode optical fiber comprises a core made of silica glass, a clad surrounding the core and made of silica glass having a smaller index of refraction than the glass comprising the core, a pair of stress applying members symmetrically disposed on the clad and made of silica glass having different thermal expansion coefficient from that of the clad, spacers interposed between the stress applying members and made of silica glass having substantially the same thermal expansion coefficient as the clad, and a jacket surrounding the spacers, stress applying members. The jacket is also made of silica glass and has a smaller expansion coefficient than the stress applying members. The optical fiber of this invention has an excellent polarization preserving characteristic, low loss, long length, and stable characteristics.
    Type: Grant
    Filed: October 29, 1987
    Date of Patent: June 13, 1989
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Takao Edahiro, Tetsuo Miya, Yutaka Sasaki, Katusunari Okamoto, Masao Kawachi
  • Patent number: 4835535
    Abstract: In a D/A converting apparatus which provides a converted analog signal at its output terminal by selectively yielding one or more currents from one or more current sources in accordance with an input digital signal, the current sources are selectively actuated to output the currents and an error in the current of each selected current source is obtained from the output derived at the output terminal in response to the outputting of the current. From the current error of each current source is computed a final error corresponding to each input digital signal and corrected data corresponding to the final error is stored in a corrected data memory, which is read out by the input digital signal. The output thus read out is converted into an analog signal, whereby a correct converted output is obtained.
    Type: Grant
    Filed: March 6, 1987
    Date of Patent: May 30, 1989
    Assignees: Nippon Telegraph & Telephone Public Corporation, Takeda Riken Kogyo Kabushikikaisha
    Inventors: Akinori Shibayama, Hironobu Niijima
  • Patent number: 4830490
    Abstract: An apparatus for aligning the centers of the cores of two optical fibers prior to their being fused together for splicing. A pair of supporting members are provided, each of which has a V-shaped recess in which an end of a respective one of the optical fibers is fixed. The supporting members are movable relative to one another in a direction substantially perpendicular to the axial direction of the optical fibers. A transparent light conducting member forms a bottom portion of the recess of at least one of the supporting members. A photodetector is optically coupled to the light conducting member.
    Type: Grant
    Filed: September 30, 1987
    Date of Patent: May 16, 1989
    Assignees: Nippon Telegraph and Telephone Public Corporation, Sumitomo Electric Industries, Ltd.
    Inventors: Toshiaki Kakii, Yuichi Toda, Yuichi Usui, Mitsuaki Osanai, Norio Kashima, Yasuyaki Kato
  • Patent number: 4812155
    Abstract: A method for producing a glass preform for optical fibers in which fluorine is efficiently incorporated into the preform without incorporation of Fe or Cu. A fine glass particle mass, made primarily of quartz, is converted into transparent glass by heating it in a gas atmosphere containing at least a fluorine-based compound gas and a chlorine-based compound gas. The preferred heating range is 1,100.degree. to 1,400.degree. C.
    Type: Grant
    Filed: December 10, 1987
    Date of Patent: March 14, 1989
    Assignees: Nippon Telegraph & Telephone Public Corporation, Sumitomo Electric Industries, Ltd.
    Inventors: Michihisa Kyoto, Naoki Yoshioka, Gotaro Tanaka, Hiroo Kanamori, Minoru Watanabe, Motohiro Nakahara
  • Patent number: 4801186
    Abstract: A coated optical fiber comprising an optical fiber; a first layer of a thermoplastic rubber composition which is disposed around the circumference of the optical fiber, has a Young's modulus of 0.1 GPa or less, and is capable of extrusion coating; and a second layer of a thermoplastic resin composition which is disposed around the circumference of the first layer, has a linear expansion coefficient of 1.times.10.sup.-5.degree. C..sup.-1 or less and a Young's modulus of 5 GPa or more, and is capable of extrusion coating. The coated optical fiber has excellent transmission characteristics at low and high temperatures and is inexpensive.
    Type: Grant
    Filed: January 17, 1985
    Date of Patent: January 31, 1989
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Makoto Wagatsuma, Fumio Yamamoto, Takao Kimura, Yoshito Shuto, Shinzo Yamakawa