Patents Assigned to Nippon Telegraph & Telephone Public Corporation
  • Patent number: 4656347
    Abstract: A method of adjusting a relative positional relationship between two objects uses a diffraction grating. A first diffraction grating is arranged on a first object located to oppose a second object, a reflecting surface is arranged at a position of the second object which corresponds to the first diffraction grating, and the method includes the step of irradiating the first diffraction grating with a radiation beam of coherent light or quasi-monochromatic light and measuring/setting the gap between the first and second objects in accordance with a change in intensity of one of the diffracted light components from the first diffraction grating.
    Type: Grant
    Filed: January 28, 1985
    Date of Patent: April 7, 1987
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Atsunobu Une, Makoto Iki, Nobuyuki Takeuchi, Kimiyoshi Deguchi
  • Patent number: 4653852
    Abstract: A multi core optical fiber made of quartz glass comprising at least two cores the centers of which are arranged substantially on one line. The distances between the centers of the adjacent cores are substantially the same in the longitudinal direction. A first cladding covers the cores and the second cladding covers the first cladding and has a larger refractive index than the first one. The fiber has improved mechanical strength and low cross-talk even if the distance between the adjacent cores is short.
    Type: Grant
    Filed: January 3, 1985
    Date of Patent: March 31, 1987
    Assignees: Sumitomo Electric Industries, Ltd, Nippon Telegraph and Telephone Public Corporation
    Inventors: Shuzo Suzuki, Ichiro Ogasawara, Hiroshi Yokota, Shim Sumida
  • Patent number: 4653594
    Abstract: A vibration generating apparatus including a support body having a first center axis, a first spherical joint element provided at a forward end of the support body and having the center of a sphere located on the first center axis, a vibrating body having a second center axis passing through the sphere center, a second spherical joint element provided on the vibrating body and concentric complementary with the first spherical joint element to cooperate therewith to allow the vibrating body to be supported on the support member for universal movement, a rotary shaft coaxially rotatably supported within the vibrating body, a pair of eccentric weights mounted on the rotary shaft with a phase deviation of 180 degrees and in a manner symmetrical with respect to the sphere center, and a drive motor connected to the rotary shaft for driving same for rotation whereby the pair of eccentric weights are rotated about the second center axis to cause the vibrating body to move in conical motion vibration such that the sec
    Type: Grant
    Filed: May 29, 1984
    Date of Patent: March 31, 1987
    Assignees: Nippon Telegraph & Telephone Public Corporation, Hitachi
    Inventors: Hiroshi Yamamoto, Shuichi Satoh, Yoshiyuki Iwai, Osamu Ae, Masao Suda, Minoru Shiozaki, Kiyoshi Tsuchiya, Manabu Nakano, Kojiro Ogata, Naoki Miyanagi, Kozo Ono, Nobuyuki Tobita
  • Patent number: 4645564
    Abstract: A semiconductor device with a metal-insulator-semiconductor capacitor has:a semiconductor substrate having a predetermined conductivity type and serving as one electrode of the metal-insulator-semiconductor capacitor, the semiconductor substrate being provided with a trench of a cross-sectionally rectangular shape which extends along a direction of thickness of the semiconductor substrate from a major surface thereof;a doped semiconductor layer formed along at least side wall surfaces of the trench, the semiconductor layer, which is formed by deposition and etching, being provided with an outer surface, starting to extend in a rounded shape from major surface portions of the semiconductor substrate and extending substantially parallel to the side wall surfaces of the trench, and a recess, which is defined by the semiconductor layer, having round corners at the bottom;a dielectric insulating layer formed on an exposed surface including the major surface of the semiconductor substrate and the outer surface of t
    Type: Grant
    Filed: March 18, 1985
    Date of Patent: February 24, 1987
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Takashi Morie, Kazushige Minegishi, Shigeru Nakajima
  • Patent number: 4644458
    Abstract: In an electric power supply circuit comprising a plurality of constant current units each of which is controllable by a control voltage (V.sub.c) to keep a circuit output current (I.sub.OUT) substantially constant and which has no shunt resistor, the control voltage is supplied from a single current to voltage converter (44) operable in response to a control current (I.sub.c) corresponding to the circuit output current. A control unit (39) produces the control current in response to a detection signal supplied from a current detector (37) and representative of a result of detection of the circuit output current. A plurality of current detectors may be coupled to a plurality of control units coupled in common to the single current to voltage converter. The single current to voltage converter may be a saturable reactor, a resistor, or the like.
    Type: Grant
    Filed: March 18, 1985
    Date of Patent: February 17, 1987
    Assignees: NEC Corporation, Nippon Telegraph & Telephone Public Corporation
    Inventors: Yoshihiko Harafuji, Hideki Yamamoto, Katsuhiko Yamamoto
  • Patent number: 4642245
    Abstract: .gamma.-Fe.sub.2 O.sub.3 film added at least one selected from the group consisting of Pd, Au, Pt, Rh, Ag, Ru, Ir, Os as additive, especially Os are disclosed. Reduction from .alpha.-Fe.sub.2 O.sub.3 to Fe.sub.3 O.sub.4 is accelerated by additive Os to accompany to a uniform reduction and increased the ratio of magnetic phase in the film. .gamma.-Fe.sub.2 O.sub.3 film medium added Os improves the saturation magnetization and increases the coercive force in proportion to amount of additive Os. Application of an external field to said film introduced magnetic anisotropy into said film, therefore said film medium improves coercive force and squareness of hysteresis loop by the grant of anisotropy. .gamma.-Fe.sub.2 O.sub.3 crystal grain is prepared by additive Os to obtained fine grain. The resultant .gamma.-Fe.sub.2 O.sub.3 film medium decreases the noise.
    Type: Grant
    Filed: May 6, 1985
    Date of Patent: February 10, 1987
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Osamu Ishii, Fumikatsu Yoshimura, Iwao Hatakeyama
  • Patent number: 4639080
    Abstract: A coating material for optical glass fibers is disclosed. The material is comprised of 1,4-polybutadienes having functional groups or modified polybutadienes derived from the 1,4-polybutadienes having introduced therein polymerizable double bonds different from the double bonds present in the 1,4-polybutadienes.
    Type: Grant
    Filed: August 28, 1984
    Date of Patent: January 27, 1987
    Assignees: Nippon Telegraph & Telephone Public Corporation, Nitto Electric Industrial Co., Ltd.
    Inventors: Takao Kimura, Nobuo Inagaki, Mitsuo Yoshihara, Fumihiko Kato
  • Patent number: 4637939
    Abstract: The adhesive composition or compound of the invention comprises an epoxy resin, a reactive diluent and a hardener, and at least one of said components contains fluorine atoms. The adhesive composition containing fluorine atoms, according to the invention, provides a cured or hardened composition having small refractive index due to the presence of fluorine atoms. The refractive index of the hardened product may be freely controlled within the range of n.sub.D.sup.23 =1.415 to n.sub.D.sup.23 =1.570.The adhesive composition may be applied for the production of optical members for use in a communication system utilizing optical fibers or in a variety of optical instruments, and has improved heat resistance and adhesive property and is improved in matching of the refractive index with that of the material used for the optical member, such as optical fibers or glasses having lower refractive index used in a lens system.
    Type: Grant
    Filed: February 7, 1986
    Date of Patent: January 20, 1987
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Tooru Maruno, Kouzaburou Nakamura, Shigekuni Sasaki
  • Patent number: 4638185
    Abstract: An analog signal measuring apparatus has: a sampling gate circuit, having a plurality of input terminals including an analog signal input terminal and a feedback signal input terminal, for generating an output signal of high or low level when a sum of input signals goes beyond or falls below a predetermined threshold value; a signal generating circuit, connected to an output terminal of the sampling gate circuit, for changing an output signal by a predetermined level toward a direction in which an output signal level of the sampling gate circuit is inverted when a trigger signal is applied to the signal generating circuit, and for supplying a feedback signal to the feedback signal input terminal of the sampling gate circuit; and a read circuit for generating a value obtained when the feedback signal from the signal generating circuit converges, the feedback signal corresponding to a value of an analog signal supplied to the analog signal input terminal, wherein a ratio of an increment .DELTA.
    Type: Grant
    Filed: November 13, 1984
    Date of Patent: January 20, 1987
    Assignees: Iwatsu Electric Co., Ltd., Nippon Telegraph & Telephone Public Corporation
    Inventors: Kensuke Kobayashi, Yasuo Tazoh
  • Patent number: 4633194
    Abstract: The frequency divider includes a first or prescaling counter which selects between first and second frequency division factors, in response to a first control signal, and then divides an input signal frequency responsive to the first control signal. A second and programmable counter frequency divides the output of the first or prescaling counter by a third frequency-division factor. A third and programmable counter frequency divides the output of the first counter by a fourth frequency-division factor which is smaller than the third frequency-division factor. A switching control circuit then converts the output of the third counter and supplies the converted signal to the first counter, as the first control signal. The digital frequency divider is suitable for use a part of a phase-locked loop frequency synthesizer.
    Type: Grant
    Filed: June 25, 1981
    Date of Patent: December 30, 1986
    Assignees: Nippon Telegraph & Telephone Public Corporation, Nippon Electric Co., Ltd.
    Inventors: Hiroyuki Kikuchi, Atsushi Iwata, Takashi Matsuura, Yoshiharu Shigeta
  • Patent number: 4633510
    Abstract: In a radio communication system, a transmitting section of a substation comprises a controlling circuit (21) for controlling a carrier frequency of a local oscillator (24) in response to a frequency deviation signal. A burst generating circuit (26) generates a burst in response to the input signal, a burst control signal, and a local oscillation signal of the carrier frequency. The transmitting section further comprises a holding circuit (34) responsive to a frequency control signal and the burst control signal. During presence of the burst control signal, the holding circuit holds the frequency control signal received before a beginning of the burst control signal to keep the carrier frequency of the local oscillation signal invariable until an end of the burst control signal. Otherwise, the frequency control signal passes through the holding circuit as it stands.
    Type: Grant
    Filed: December 28, 1984
    Date of Patent: December 30, 1986
    Assignees: NEC Corporation, Nippon Telegraph & Telephone Public Corporation
    Inventors: Fumiaki Suzuki, Toshiyuki Takeda, Takeo Inoue, Shigeo Nakajima
  • Patent number: 4631721
    Abstract: In a communication system comprising a two-wire bus, bidirectional communication is carried out in a time division multiple access fashion through the two-wire bus between a plurality of terminal equipments (26) coupled to the two-wire bus and a central terminator (24) connected to one end of the two-wire bus which has the other end terminated by an active terminator (25). The central terminator transmits, to the two-wire bus, a down burst comprising a down synchronization signal and a down information signal. Each terminal equipment establishes synchronization with reference to the down synchronization signal and thereafter receives the down information signal. The active terminator sends, towards the central terminator, only an up synchronization signal produced with reference to the down synchronization signal extracted from the down burst. Each terminal equipment transmits an up information signal towards the central terminator in the form of an up burst with reference to the up synchronization signal.
    Type: Grant
    Filed: August 15, 1984
    Date of Patent: December 23, 1986
    Assignees: NEC Corporation, Nippon Telegraph & Telephone Public Corporation
    Inventors: Tatsuhiro Ono, Shin'ichi Koike, Haruhiko Tsuchiya, Yuji Inoue
  • Patent number: 4627866
    Abstract: A method for producing an optical fiber preform comprising injecting a glass raw material, a gaseous fluorine-containing material and oxygen gas from a first nozzle, inactive gas from a second nozzle which surrounds the first nozzle and hydrogen gas from a third nozzle which surrounds the second nozzle, flame hydrolyzing the glass raw material to synthesis fine glass particles and depositing the fine glass particles on a tip of a rotating seed rod to produce the optical fiber preform containing fluorine.
    Type: Grant
    Filed: December 6, 1984
    Date of Patent: December 9, 1986
    Assignees: Sumitomo Electric Industries Ltd., Nippon Telegraph and Telephone Public Corporation
    Inventors: Hiroo Kanamori, Gotaro Tanaka, Kazunori Chida
  • Patent number: 4625076
    Abstract: On the transmitting side, a signature corresponding to a document to be transmitted is generated using a random number and the document as variables and on the basis of a congruent polynomial of second or higher degree with respect to the random number, secret key information and public key information produced based on the secret key information. The signature and the document are transmitted in digital form. On the receiving side, the congruent polynomial is operated using the received signature and document in place of the random number and the document employed on the transmitting side, and the validity of the received signature and document is verified on the basis of the result of the operation and the public key information.
    Type: Grant
    Filed: March 11, 1985
    Date of Patent: November 25, 1986
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Tatsuaki Okamoto, Shoji Miyaguchi, Akira Shiraishi, Tsukasa Kawaoka
  • Patent number: 4622480
    Abstract: In a switched capacitor circuit, in order to eliminate leakage of a power supply noise component to a signal line through an input capacitance of an operation amplifier, (1) an operating current of at least a first, differential stage among stages of the operational amplifier is regulated by a current regulation bias circuit, and (2) a power supply noise component having the same phase as that of an input signal is applied to the gate of a transistor of a gain stage, thereby stabilizing the operating point. In order to eliminate leakage of the power supply noise component to the signal line through a parasitic capacitance of an analog switch, (3) a dummy switch is used to detect a signal corresponding to the leakage component of the power supply noise component to the signal line, and an inverted signal having the opposite phase to that of the signal corresponding to the leakage component is applied to a substrate of the analog switch, thereby cancelling the actual leakage component.
    Type: Grant
    Filed: April 22, 1983
    Date of Patent: November 11, 1986
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Kuniharu Uchimura, Atushi Iwata
  • Patent number: 4621368
    Abstract: Fast and deep fading tends to occur in the communication between a fixed base station and a mobile station which is carried on an automobile travelling in an urban area. When connection control signals or other digital code pattern need to be transmitted between the mobile station and the fixed station, it is necessary to provide a protection system against fading. This invention relates to a protection system of the type wherein a transmitter repeats identical information for plural times and by inverting polarity. The bit error rate against fading will be thus improved and moreover, even if there is a deviation in the pattern arrangement of codes, the DC component unbalance may be avoided. The receiver evaluates the receiving condition and receives selectively the identical information which has been repeatedly transmitted. The invention provides plural circuit systems which are effective for evaluation and selection.
    Type: Grant
    Filed: June 27, 1984
    Date of Patent: November 4, 1986
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Seizo Onoe, Takeshi Hattori
  • Patent number: 4619695
    Abstract: A high-purity high-melting metal target or high-purity high-melting metal silicide target for LSI electrodes having an alkali metal content of not more than 100 ppb and a radioactive element content of not more than 10 ppb is provided by a wet purification process followed by a series of dry processings. Preferably the high-melting metal is molybdenum, tungsten, titanium, niobium or tantalum. More preferably, the high-melting metal is molybdenum.
    Type: Grant
    Filed: July 26, 1984
    Date of Patent: October 28, 1986
    Assignees: Nihon Kogyo Kabushiki Kaisha, Nippon Telegraph & Telephone Public Corporation
    Inventors: Hideo Oikawa, Takao Amazawa, Nakahachiro Honma, Hideo Miyazaki, Iwao Kyono, Nobuyuki Mori, Yoshiharu Katoh, Masami Kuroki
  • Patent number: 4618901
    Abstract: A magnetic head for digital signal recording/reproducing (FIG. 11) having a C-ring shaped core (11.1) with a gap (G) for introducing leakage flux of a recording medium, a conductor (11.2, Y) for generating bias flux in hard magnetization axis of the core (11.1), apparatus (10.3, 11.3) for illuminating the core (11.1) with polarized optical beam, apparatus (11.4) for analyzing beam reflected by the core to convert polarization rotation to optical strength, and photo-detector (12.5) for providing electrical output signal relating to optical strength. The core is small enough to have a single magnetic domain, and is magnetized in the whole area because of the presence of the bias flux in spite of weak leakage signal flux, thus, the core has the capability to amplify signal flux, thus, the present head has high sensitivity and is capable of detecting flux in small area to be used for high density recording higher than 8000 bits/mm.
    Type: Grant
    Filed: July 19, 1983
    Date of Patent: October 21, 1986
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Iwao Hatakeyama, Yasushi Maeda, Osamu Ishii, Shizuka Yoshii
  • Patent number: 4618354
    Abstract: In an optical fiber preform fabrication method having the steps of decomposing a glass raw material in a flame so that fine glass particles are produced; depositing the fine glass particles on a seed rod to form a porous preform; and consolidating the porous preform into a transparent optical fiber preform, use is made of a burner having a raw material supply orifice for supplying the glass raw material and a plurality of flame forming orifices disposed around the raw material supply orifice sequentially for forming a plurality of flames, respectively. The flame speed V.sub.k of a kth flame, the flame speed V.sub.k+1 of a (k+1)th flame surrounding outwardly of the kth flame and the flow speed Vm of the glass raw material are determined in a suitable manner. The glass raw material is supplied to the maluti-flame produced by the burner in which the kth flame is positioned rearwardly of the (k+1)th flame to synthesize the fine glass particles.
    Type: Grant
    Filed: February 25, 1985
    Date of Patent: October 21, 1986
    Assignee: Nippon Telegraph & Telephone Public Corporation
    Inventors: Hiroyuki Suda, Shuichi Shibata, Motohiro Nakahara
  • Patent number: 4608464
    Abstract: In an interface circuit which couples a two-wire line of bidirectional transmission and unidirectional four-wire receiving and transmitting lines; in order to permit the interface circuit to operate in adaptation to the fluctuation of an impedance with the two-wire line side viewed from the four-wire receiving line, the four-wire receiving line is provided with a plurality of filters and a group of switches for selecting the filters, an output of the four-wire transmitting line is compared with outputs obtained by scanning the filters, and the filter providing the minimum output difference in the comparisons is selected and connected.
    Type: Grant
    Filed: May 1, 1984
    Date of Patent: August 26, 1986
    Assignees: Nippon Telegraph & Telephone Public Corporation, Hitachi, Ltd.
    Inventors: Yuichi Morikawa, Hirohiko Sato, Eiichi Amada, Toshiro Suzuki, Hirotoshi Shirasu, Hiroshi Kuwahara