Patents Assigned to Nippon Telegraph & Telephone Corporation
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Patent number: 5396569Abstract: An optical line monitoring method and an apparatus for locating a failure point in an optical communication system, wherein a plurality of types of inspection light rays having wavelengths which are determined by cut-off wavelengths, which differ from each other, of short-wavelength pass filters installed at a plurality of branched ports of an optical coupler/splitter of the communication system are sent from a light source having variable wavelengths into one or more corresponding optical fiber lines of the system in sequence via an optical directional coupler and the optical coupler/splitter. Each time reflected light, corresponding to the inspection light, from one or more optical fiber lines is received, an output representing the intensity level of the reflected light is sent from a light receiver to an arithmetic circuit and stored in the arithmetic circuit.Type: GrantFiled: October 1, 1993Date of Patent: March 7, 1995Assignees: The Furukawa Electric Co., Ltd., Nippon Telegraph & Telephone CorporationInventors: Hisaharu Yanagawa, Takeo Shimizu, Shiro Nakamura, Isao Ohyama, Izumi Sankawa
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Patent number: 5396576Abstract: An excitation vector of the previous frame stored in an adaptive codebook is cut out with a selected pitch period. The excitation vector thus cut out is repeated until one frame is formed, by which a periodic component codevector is generated. An optimum pitch period is searched for so that distortion of a reconstructed speech obtained by exciting a linear predictive synthesis filter with the periodic component codevector is minimized. Thereafter, a random codevector selected from a random codebook is cut out with the optimum pitch period and is repeated until one frame is formed, by which a repetitious random codevector is generated. The random codebook is searched for a random codevector which minimizes the distortion of the reconstructed speech which is provided by exciting the synthesis filter with the repetitious random codevector.Type: GrantFiled: May 20, 1992Date of Patent: March 7, 1995Assignee: Nippon Telegraph and Telephone CorporationInventors: Satoshi Miki, Takehiro Moriya, Kazunori Mano, Hitoshi Ohmuro, Hirohito Suda
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Patent number: 5396082Abstract: The semiconductor device has a semiconductor substrate composed essentially of a III-V compound semiconductor containing Ga and As, and a surface layer structure provided on the semiconductor substrate and this layer has a composition different from that of the semiconductor substrate. The surface layer structure includes a strained layer epitaxially grown on the surface of the semiconductor substrate and composed essentially of at least one-element selected from the group consisting of indium, gallium, aluminum and boron, and at least one element selected from the group consisting of arsenic and phosphorus. The strained layer has a composition different from that of the semiconductor substrate The strained layer has a valence band maximum lower in energy than that of the valence band maximum of the semiconductor substrate.Type: GrantFiled: March 4, 1994Date of Patent: March 7, 1995Assignee: Nippon Telegraph & Telephone CorporationInventors: Yoshinori Wada, Kazumi Wada, Takahisa Ohno
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Patent number: 5394235Abstract: An apparatus for measuring a distortion position of an optical fiber is disclosed. A light source generates continuous light with frequency f.sub.0 and injects the continuous light into a far-end of an optical fiber to be measured. An optical coupler divides the outgoing continuous light from a near-end of the optical fiber. An optical amplifier amplifies output light from the optical coupler. A first optical switch generates a first optical pulse by switching output light from the optical amplifier. An optical frequency shifter generates a second optical pulse having frequency components (f.sub.0 +f.sub.m) based on the first optical pulse from the first optical switch. A second optical switch injects the second optical pulse into the near-end of the optical fiber. A display displays outgoing continuous light with frequency f.sub.0 from the near-end of the optical fiber via the optical coupler and the second optical switch.Type: GrantFiled: March 16, 1994Date of Patent: February 28, 1995Assignees: Ando Electric Co., Ltd., Nippon Telegraph and Telephone CorporationInventors: Nobunari Takeuchi, Tekken Lee, Kaoru Shimizu, Tsuneo Horiguchi
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Patent number: 5394408Abstract: A policing control apparatus having a cell input terminal receiving asynchronous transmission communication network cells; a policing circuit coupled to the input terminal for policing transmission of cells according to policing information; a cell output terminal from the policing circuit for outputting policed cells; a count memory in the policing circuit for storing a count value of the cells supplied to the policing circuit and for supplying the count value as the policing information; and a self-diagnosing circuit for monitoring problems and abnormalities of stored contents in the count memory and outputting an alarm upon detection of a problem or abnormality.Type: GrantFiled: February 8, 1993Date of Patent: February 28, 1995Assignees: NEC Corporation, Nippon Telegraph and Telephone CorporationInventors: Motoo Nishihara, Takatoshi Kurano, Naoaki Yamanaka, Youichi Sato
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Patent number: 5390345Abstract: A signal which results from cross modulation of two or more nearby received waves contained in the output of a high-frequency amplifier or mixer of a radio receiver, for example, a low-frequency signal corresponding to a channel separation frequency is extracted. The gain of the high-frequency amplifier or attenuation of a variable attenuator provided in the preceding stage of the amplifier is controlled in accordance with the level of the low-frequency signal. Alternatively, the gain of the high-frequency amplifier or attenuation of the variable attenuator is controlled in accordance with the level of the low-frequency signal when it is equal to or larger than a predetermined value. This permits normal reception of a desired wave, even if the signal receiving level is high.Type: GrantFiled: March 30, 1992Date of Patent: February 14, 1995Assignees: Nippon Telegraph and Telephone Corporation, Toyo Communication Equipment Co., Ltd.Inventors: Masahiro Wada, Kazuo Tominaga
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Patent number: 5389492Abstract: A resist composition comprising a compound having an active hydrogen and an alkali-soluble siloxane polymer containing in the molecules thereof at least one unit selected from a unit represented by formula (I) and a unit represented by formula (II) ##STR1## wherein the X's are the same or different and each represents one member selected from the group consisting of hydrogen, ##STR2## (where R represents hydrogen, a hydrocarbon group, or a substituted hydrocarbon group); and a carboxyl group;R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are the same or different and each represents one member selected from the group consisting of hydrogen, a hydroxyl group, a substituted or unsubstituted aliphatic hydrocarbon group, and a substituted or unsubstituted aromatic hydrocarbon group, provided that at least one of R.sub.1 to R.sub.6 is a hydroxyl group; andl, m, n, and p each is 0 or a positive integer, provided that l and m are not 0 at the same time.Type: GrantFiled: April 8, 1994Date of Patent: February 14, 1995Assignees: Fuji Photo Film Co., Ltd., Nippon Telegraph and Telephone CorporationInventors: Tadayoshi Kokubo, Atsushi Sakamoto, Akinobu Tanaka, Hiroshi Ban
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Patent number: 5390252Abstract: In a first processing mode for a first communication request, a communication processing unit responds to a communication request signal from a communication terminal to acquire an authentication key Ka corresponding thereto from a storage, generates pieces of enciphered authentication information Xai and Xbi enciphered by the authentication key Ka of the communication terminal and an authentication key Kb of the communication processing unit, respectively, and random information Yi and transmits these pieces of information Xai, Xbi and Yi as an authentication request signal to the communication terminal. The communication terminal sends, as an authentication response signal, information Ka[Yi] obtained by enciphering the received random information Yi with the authentication key Ka, back to the communication processing unit, and at the same time, the communication terminal stores the received enciphered pieces of authentication information Xai and Xbi.Type: GrantFiled: December 22, 1993Date of Patent: February 14, 1995Assignee: Nippon Telegraph and Telephone CorporationInventors: Shigefusa Suzuki, Tatsuo Nohara
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Patent number: 5390018Abstract: An optical pulse tester capable of displaying Raman scattered light is disclosed. An optical pulse with the specified wavelength is injected into an optical fiber to be measured via a directional coupler and an optical demultiplexer/multiplexer. The demultiplexer/multiplexer demultiplexes returning light from the optical fiber into Raman scattered light different from the optical pulse in wavelength. The directional coupler divides returning light from the optical fiber into Fresnel reflection light and Rayleigh scattered light with the specified wavelength. The switcher supplies the Rayleigh scattered light to a display In the case of long distance measurement or precise loss measurement of the optical fiber. Therefore, the display displays the characteristic waveform of the optical fiber with the Rayleigh scattered light.Type: GrantFiled: March 16, 1994Date of Patent: February 14, 1995Assignees: Ando Electric Co., Ltd., Nippon Telegraph and Telephone CorporationInventors: Tatsuyuki Fujita, Mikio Maeda, Toshiya Sato, Tsuneo Horiguchi
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Patent number: 5389215Abstract: In an electrochemical detection method using an apparatus including a first vessel and a second vessel, a reference electrolytic solution in the second vessel, first and second closely spaced working electrodes immersed in a sample solution for measurement in the first vessel, a stripping electrode immersed in the reference electrolytic solution, and an ionic conductor arranged between the first vessel and the second vessel, the reference electrolytic solution contains an electrolyte which can be deposited and dissolved by an electrochemical reaction by applying a potential to the stripping electrode. In a first stage, a pre-electrolysis potential is applied to the first working electrode with the stripping electrode being connected to the second working electrode to deposit the electrolyte in the reference electrolytic solution on the stripping electrode.Type: GrantFiled: April 27, 1993Date of Patent: February 14, 1995Assignee: Nippon Telegraph and Telephone CorporationInventors: Tsutomu Horiuchi, Osamu Niwa, Hisao Tabei, Masao Morita
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Patent number: 5387798Abstract: A UV-A, UV-B discriminating sensor provided with a photochromic compound or photochromic composition as the sensor portion, the photochromic compound or photochromic composition coloring under exposure to UV of wavelength greater than or equal to 280 nm or less than or equal to 400 nm, and wherein at least a portion of the photochromic layer is covered with a layer containing a pigment which absorbs UV of wavelength less than 320 nm, or with a layer containing a pigment which absorbs UV of a wave length greater than or equal to 320 nm but less than or equal to or equal to 400 nm.Type: GrantFiled: February 9, 1994Date of Patent: February 7, 1995Assignee: Nippon Telegraph and Telephone CorporationInventors: Nobuhiro Funakoshi, Fumihiro Ebisawa, Mitsutoshi Hoshino, Takashi Yoshida, Ken Sukegawa, Akira Morinaka, Norio Sashida, Shigeko Toeda, Miwa Urabe
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Patent number: 5386485Abstract: There is disclosed an optical fiber switching device having a coupling board comprising a plurality of first optical fibers connected to one surface of the coupling board in the arrangement to one surface of the coupling board, a plurality of second optical fibers connected to the another surface of the coupling board, an optical fiber length adjusting unit for handling surplus portions of the second optical fibers and switching unit for pulling out any one of the second optical fibers selected from the plural second optical fibers from the another surface of the connecting board and for connecting the any one optical fiber to different switching position of the another surface of the connecting board to coupling the any one optical fiber with any one of the first optical fibers.Type: GrantFiled: February 25, 1993Date of Patent: January 31, 1995Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph and Telephone CorporationInventors: Kazuhito Saito, Masayuki Nishimura, Tohru Yamanishi, Hideo Kobayashi, Toshiaki Katagiri, Masao Tachikura
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Patent number: 5384809Abstract: A serial-parallel converter is arranged to convert an information sequence into a plurality of bit sequences. Two convolutional encoders are provided which respectively receive bit sequences from the serial-parallel converter. Each of the two convolutional encoders outputs first and second bit sequences. First parallel-serial converter receives the first bit sequences and converts them into third bit sequence, while second parallel-serial converter receives the second bit sequences and converts them into fourth bit sequence. The third and fourth bit sequences are used to modulate two carriers with a phase difference of .pi./2 radians.Type: GrantFiled: December 23, 1993Date of Patent: January 24, 1995Assignees: Nippon Telegraph and Telephone Corporation, NEC CorporationInventors: Toshiharu Yagi, Shuzo Kato, Shuji Kubota
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Patent number: 5382532Abstract: A method for fabricating semiconductor devices wherein polysilicon gates for complementary-type field-effect semiconductor devices are formed of polysilicon to which impurity doped simultaneously to the polysilicon deposition; the both gates having the dual N.sup.+ /P.sup.+ polysilicon gate structure, so that the both N- and P-channel transistors are formed as the surface-channel type ones; and therefore, the off-characteristic, the short channel effect, and the controllability of threshold voltage are progressed. More specifically, N- and P-channel MISFETs are provided on a common semiconductor substrate (1); N-type polysilicon (9) doped with N-type impurity is adopted as the gate electrode for the N-channel MISFET; P-type polysilicon (8) doped with P-type impurity is adopted as the gate electrode for the P-channel MISFET; and a narrow region preventing the mutual diffusion of impurities is provided between portions of respective polysilicon.Type: GrantFiled: September 16, 1992Date of Patent: January 17, 1995Assignee: Nippon Telegraph and Telephone CorporationInventors: Toshio Kobayashi, Yukio Okazaki, Masayasu Miyake, Hiroshi Inokawa, Takashi Morimoto
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Patent number: 5381503Abstract: There is disclosed an optical waveguide comprising a core portion made of a light propagating material and a cladding portion, a first dopant and a second dopant being induced into said core portion, the first dopant having a function of increasing a refractive index of the light propagating material and having a first thermal diffusion coefficient to said light propagating material, the second dopant having a function of decreasing the refractive index of said light propagating material and having a second thermal diffusion coefficient to the light propagating material larger than the first thermal diffusion coefficient under a predetermined temperature.Type: GrantFiled: May 14, 1993Date of Patent: January 10, 1995Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph and Telephone CorporationInventors: Hiroo Kanamori, Koji Nakazato, Masayuki Nishimura, Shigeru Tomita
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Patent number: 5379225Abstract: A method for efficient calculation of the movement of a vertex in a three-dimensional topography simulator. The method is particularly well suited for calculating vertex movement for cases in which an etch/deposition rate depends on the angle between the surface normal and the vertical direction. A workpiece is represented as a collection of material solids. Each of the material solids has a boundary model representation, which include vertices, edges and faces. The method of the present invention generally includes the steps of: identifying a first plane, a second plane and a third plane that approximate all the planes that are adjacent to a vertex point to be moved; determining a first observation vector; creating a set of advanced virtual planes; identifying a second observation vector; determining the furthest intersection point of one of the planes in the set of advanced planes and the second observation vector; and moving the vertex to the point identified in the prior step.Type: GrantFiled: June 24, 1992Date of Patent: January 3, 1995Assignees: Intel Corporation, Nippon Telegraph and Telephone CorporationInventors: Satoshi Tazawa, Francisco A. Leon, Donald L. Sharfetter, Kazuyuki Saito, Akira Yoshii
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Patent number: 5377294Abstract: An optical functioning glass for enabling optical amplification at 1.3-.mu.m wavelength band or increasing efficiency of the amplification is disclosed. The optical functioning glass contains Nd.sup.3+ as an active material and uranium, both of which are doped in a multi-component function glass serving as a host glass. Since uranium is doped in the optical functioning glass, light emission of Nd.sup.3+ in the 1.06-.mu.m wavelength band can be absorbed by uranium. A decrease in efficiency of induced emission in a 1.3-.mu.m wavelength band can be prevented, and an optical functioning glass suitable for optical amplification in the 1.3-.mu.m wavelength band can be obtained. When a fiber is formed using the optical functioning glass as a core, a low-threshold, high-gain fiber amplifier, fiber laser, and the like can be obtained.Type: GrantFiled: June 18, 1993Date of Patent: December 27, 1994Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph and Telephone CorporationInventors: Masahi Onishi, Koji Nakazato, Hiroo Kanamori, Minoru Watanabe, Yoshiaki Miyajima
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Patent number: 5376590Abstract: A semiconductor device includes an interlevel film constituted by a first dielectrics film containing dangling bonds and a bonded group of Si and hydrogen, and a second dielectrics film formed on the first dielectrics film.Type: GrantFiled: January 19, 1993Date of Patent: December 27, 1994Assignee: Nippon Telegraph and Telephone CorporationInventors: Katsuyuki Machida, Katsumi Murase, Nobuhiro Shimoyama, Toshiaki Tsuchiya, Junichi Takahashi, Kazushige Minegishi, Yasuo Takahashi, Hideo Namatsu, Kazuo Imai
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Patent number: 5377267Abstract: A method of subscriber authentication suitable for a roaming service in a telecommunication capable of realizing an improved security for the secrecy of the authentication key. In this method, an authentication data Indicative of a tentative authentication key to be used only in the authentication at the second network is transmitted from the second network to the first network, and the first network enciphers this authentication data by using a permanent authentication key shared between the first network and the mobile subscriber, and transmits this enciphered authentication data to the mobile subscriber via the second network, such that the mobile subscriber can decipher this enciphered authentication data by using the permanent authentication key to obtain the tentative authentication key and subsequently carry out the authentication at the second network by using the obtained tentative authentication key, wlthout explicitly disclosing the permanent authentication key to the second service provider.Type: GrantFiled: August 16, 1993Date of Patent: December 27, 1994Assignee: Nippon Telegraph and Telephone CorporationInventors: Shigefusa Suzuki, Tatsuo Nohara
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Patent number: 5374937Abstract: An antenna element (1) has a linear antenna rod (1b) of predetermined length and a top load (1a) at the end of the rod (1b). The antenna element (1) takes a first position in which the rod is extended out of a housing (8), and a second position in which the rod is retracted within the housing. There are provided two feed terminals (5, 6) along the rod (1b). The first feed terminal (5) is essentially matching the impedance of a node point in a current distribution in the resonant antenna element, and feeds the antenna element at the end of the rod in the first position. The second feed terminal (5) is matching the impedance of an anti-node point in a current distribution in the resonant antenna element, and feeds the antenna element at approximate center of the rod in the second position. A first feed terminal (5) might contact the rod in a second position, but it does not feed the same because of mismatching.Type: GrantFiled: January 28, 1994Date of Patent: December 20, 1994Assignee: Nippon Telegraph and Telephone CorporationInventors: Koichi Tsunekawa, Atsuya Ando