Patents Assigned to Nippon Telegraph and Telephone Public Corporation
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Patent number: 7187769Abstract: 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: GrantFiled: June 1, 1999Date of Patent: March 6, 2007Assignee: Nippon Telegraph and Telephone Public CorporationInventors: Shiho Moriai, Kazumaro Aoki, Masayuki Kanda, Youichi Takashima, Kazuo Ohta
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Patent number: 7180341Abstract: 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: GrantFiled: May 17, 2004Date of Patent: February 20, 2007Assignee: Nippon Telegraph and Telephone Public CorporationInventors: Mitsuru Harada, Akihiro Yamagishi
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Patent number: 5786105Abstract: 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: GrantFiled: July 26, 1996Date of Patent: July 28, 1998Assignee: Nippon Telegraph and Telephone Public CorporationInventors: Toshio Matsushima, Daisuke Ikeda, Himeko Kanagawa
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Patent number: 5661560Abstract: 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: GrantFiled: May 29, 1996Date of Patent: August 26, 1997Assignee: Nippon Telegraph and Telephone Public CorporationInventor: Yoshiharu Ozaki
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Patent number: 5548401Abstract: 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: GrantFiled: August 19, 1994Date of Patent: August 20, 1996Assignee: Nippon Telegraph and Telephone Public CorporationInventor: Yoshiharu Ozaki
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Patent number: 5379361Abstract: 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: GrantFiled: March 25, 1993Date of Patent: January 3, 1995Assignees: NGK Insulators, Ltd., Nippon Telegraph & Telephone Public CorporationInventors: Koichiro Maekawa, Takashi Ota, Masashi Fukuyama, Shinji Nagasawa
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Patent number: 5280469Abstract: 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: GrantFiled: June 18, 1992Date of Patent: January 18, 1994Assignees: Fujitsu Limited, Nippon Telegraph and Telephone Public CorporationInventors: Ikuo Taniguchi, Kenji Narita, Kenichi Hashimoto
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Patent number: 5097204Abstract: 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: GrantFiled: October 3, 1990Date of Patent: March 17, 1992Assignee: Nippon Telegraph and Telephone Public CorporationInventors: Masahiro Yoshizawa, Akira Kikuchi, Kou Wada, Minpei Fujinami, Nobuo Shimazu
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Patent number: 4980639Abstract: 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: GrantFiled: March 3, 1988Date of Patent: December 25, 1990Assignee: Nippon Telegraph and Telephone Public CorporationInventors: Masahiro Yoshizawa, Akira Kikuchi, Kou Wada, Minpei Fujinami, Nobuo Shimazu
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Patent number: 4975102Abstract: 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: GrantFiled: October 19, 1988Date of Patent: December 4, 1990Assignees: Nippon Telegraph & Telephone Public Corporation, Sumitomo Electric Industries, Ltd.Inventors: Takeo Edahiro, Shiro Kurosaki, Minoru Watanabe
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Patent number: 4966434Abstract: 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: GrantFiled: August 21, 1984Date of Patent: October 30, 1990Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph and Telephone Public CorporationInventors: Shinichi Yonechi, Yukinori Ishida, Masaaki Kawase
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Patent number: 4878933Abstract: 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: GrantFiled: December 16, 1986Date of Patent: November 7, 1989Assignees: Fujikura Ltd., Nippon Telegraph & Telephone Public CorporationInventors: Takeshi Yamada, Yasukuni Osato, Okosu Watanabe, Masao Suzuki, Osamu Kawata, Koushi Ishihara
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Patent number: 4863554Abstract: 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: GrantFiled: February 20, 1987Date of Patent: September 5, 1989Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph & Telephone Public CorporationInventors: Akihisa Kawasaki, Toshihiro Kotani, Ryusuke Nakai, Shintaro Miyazawa, Keigo Hoshikawa
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Patent number: 4857001Abstract: 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: GrantFiled: April 6, 1988Date of Patent: August 15, 1989Assignees: Nippon Telegraph & Telephone Public Corporation, Nippon Electric Co., Ltd., Japan Aviation Electronics Industry LimitedInventors: Kenichi Nakano, Yoshihiro Umezawa, Tetsuro Tokaichi, Yoshiaki Ichimura, Natsuki Kawabe
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Patent number: 4850022Abstract: 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: GrantFiled: October 11, 1988Date of Patent: July 18, 1989Assignee: Nippon Telegraph and Telephone Public CorporationInventors: Masaaki Honda, Takehiro Moriya
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Patent number: 4838916Abstract: 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: GrantFiled: October 29, 1987Date of Patent: June 13, 1989Assignee: Nippon Telegraph & Telephone Public CorporationInventors: Takao Edahiro, Tetsuo Miya, Yutaka Sasaki, Katusunari Okamoto, Masao Kawachi
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Patent number: 4835535Abstract: 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: GrantFiled: March 6, 1987Date of Patent: May 30, 1989Assignees: Nippon Telegraph & Telephone Public Corporation, Takeda Riken Kogyo KabushikikaishaInventors: Akinori Shibayama, Hironobu Niijima
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Patent number: 4830490Abstract: 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: GrantFiled: September 30, 1987Date of Patent: May 16, 1989Assignees: Nippon Telegraph and Telephone Public Corporation, Sumitomo Electric Industries, Ltd.Inventors: Toshiaki Kakii, Yuichi Toda, Yuichi Usui, Mitsuaki Osanai, Norio Kashima, Yasuyaki Kato
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Patent number: 4812155Abstract: 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: GrantFiled: December 10, 1987Date of Patent: March 14, 1989Assignees: Nippon Telegraph & Telephone Public Corporation, Sumitomo Electric Industries, Ltd.Inventors: Michihisa Kyoto, Naoki Yoshioka, Gotaro Tanaka, Hiroo Kanamori, Minoru Watanabe, Motohiro Nakahara
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Patent number: 4801186Abstract: 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: GrantFiled: January 17, 1985Date of Patent: January 31, 1989Assignee: Nippon Telegraph & Telephone Public CorporationInventors: Makoto Wagatsuma, Fumio Yamamoto, Takao Kimura, Yoshito Shuto, Shinzo Yamakawa