Patents Assigned to Nippon Telegraph & Telephone Public Corp.
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Patent number: 4414665Abstract: A memory device under test is accessed by an address generated by a pattern generator to write therein data and to read the data out to be compared with expected data, and the comparison result is stored in the fault-address memory by the same address after reading out therefrom the content of the address. When a disagreement is detected through the comparison, it is counted; however, the count operation is inhibited if the data read out from the fault-address memory is a fault data. When the counted number exceeds a predetermined value, a fault signal is generated. After the test is terminated, an address counter is operated, the fault-address memory is read out by the content of the address counter, and when fault data is detected from the output read out, the content of the address counter is fetched into the CPU.Type: GrantFiled: November 14, 1980Date of Patent: November 8, 1983Assignees: Nippon Telegraph & Telephone Public Corp., Takeda Riken Kogyo KabushikikaishaInventors: Kenji Kimura, Shigeru Sugamori, Kohji Ishikawa, Naoaki Narumi
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Patent number: 4402081Abstract: A semiconductor memory test pattern generating apparatus in which an instruction memory is read out, assigning an address by a program counter, and instructions thus read out are decoded and executed to generate a test pattern. A start address and a stop address and index data indicating the number of times of executing an area defined by the start and stop addresses are stored in a loop memory. During the operation of the program counter the start and stop addresses and the index data are read out from the loop memory and loaded in a register group. When the program counter coincides with the loaded stop address, the setting of the program counter to the loaded start address is executed by the number of times indicated by the loaded index data, and in the last execution the next address of the loop memory is read out.Type: GrantFiled: October 8, 1980Date of Patent: August 30, 1983Assignees: Nippon Telegraph & Telephone Public Corp., Takeda Riken Kogyo Kabushiki KaishaInventors: Yoshichika Ichimiya, Tsuneta Sudo, Masao Shimizu
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Patent number: 4393577Abstract: In a semiconductor device of the type comprising a semiconductor substrate made of P type silicon, a P type monocrystalline silicon region formed on the major surface of the substrate and containing a P type impurity, and a porous silicon oxide region surrounding the P type silicon region, the porous silicon oxide region is made to contact all side surfaces of the P type silicon region and all or at least a portion of the bottom surface thereof.Type: GrantFiled: December 11, 1981Date of Patent: July 19, 1983Assignee: Nippon Telegraph & Telephone Public Corp.Inventor: Kazuo Imai
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Patent number: 4379001Abstract: In a semiconductor device such as a bipolar transistor and a field effect transistor of the type having a substrate, a doped polycrystalline silicon region selectively formed on the substrate and an insulating film overlying the polycrystalline silicon region, the region is shaped as mesa having side surfaces with a negative coefficient of gradient between the substrate and the top of the mesa.Type: GrantFiled: July 18, 1979Date of Patent: April 5, 1983Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Tetsushi Sakai, Yoshiji Kobayasi, Yousuke Yamamoto, Hironori Yamauchi
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Patent number: 4376795Abstract: An image sensor having a photoconductor array comprising tightly adherent CdS-CdSe or CdS-CdTe photoconductive solid solution thin film and having fast photoresponse speed and excellent spectral sensitivity characteristics.Type: GrantFiled: September 8, 1981Date of Patent: March 15, 1983Assignees: Nippon Telegraph & Telephone Public Corp., Matsushita Electric Industrial Co., Ltd., Matsushita Graphic Communication Systems, Inc.Inventors: Kazumi Komiya, Toshio Yamashita, Masaru Ohno
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Patent number: 4370744Abstract: A time division multiplex communication circuit is constituted by a set of loop shaped transmission line pairs which transmits time division multiplexed signals via a clockwise transmission line and a counterclockwise transmission line, a center office connected to starting and terminal ends of the transmission line pair, and a plurality of local offices located at intermediate points of the transmission line pair. The center office includes a device connected to the starting and terminal ends of the transmission line pair for transmitting and receiving signals therewith, and a processing means for assigning time slots of time division multiplexed channels of the transmission line pairs to signals to be sent to the transmission line pairs and for sending an interoffice signal regarding the assignment of the time slots to the local offices.Type: GrantFiled: February 28, 1980Date of Patent: January 25, 1983Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Junzo Hirano, Yukio Inoue
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Patent number: 4369511Abstract: A semiconductor memory test equipment which reads out a memory under test by an address from a pattern generator and compares the read-out data with an expected value by a comparator, and in which a block mask memory is read out by a portion of the address and the comparing operation of the comparator is inhibited by block mask data read out from the block mask memory. Pattern data for a pattern memory, which is read out by the abovesaid address to store data to be supplied to the comparator, are transferred as parallel data from a central processor and written in the pattern memory after conversion to serial data, and serial data read out from a defective address memory are inputted to the central processor after conversion to parallel data.Type: GrantFiled: November 10, 1980Date of Patent: January 18, 1983Assignees: Nippon Telegraph & Telephone Public Corp., Takeda Riken Kogyo Kabushiki KaishaInventors: Kenji Kimura, Kohji Ishikawa, Naoaki Narumi
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Patent number: 4368385Abstract: In an optoelectronic switch, a photodiode is used as an optical-to-electrical converter in which a first semiconductor including a p-n junction is combined with a second semiconductor having a narrower energy band gap than the first semiconductor to form a heterojunction. When supplied with a light signal modulated by an electrical signal, the photodiode becomes ON or OFF depending upon the magnitude of a reverse bias voltage applied to said photodiode. A source for applying the bias voltage to the photodiode comprises two voltage sources of the same polarity or a single voltage source. The optoelectronic switch, has a high isolation ratio and broad transmission bandwidth, consumes little electrical power and produces low cross-talk levels when used in switching arrays.Type: GrantFiled: December 12, 1980Date of Patent: January 11, 1983Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Hiroshi Kanbe, Elmer H. Hara
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Patent number: 4366347Abstract: An exchange center is connected to telephone lines and a telephone and a data transmitter as terminal equipment are connected to the telephone lines. The data transmitter is actuated depending upon the polarity of DC voltage applied to the telephone lines. The telephone line is potentially opened by detecting the current of the telephone during the operation of the data transmitter. The impedance of the telephone line during the opening state is detected whereby the operation of the data transmitter is stopped by inverting the DC voltage applied to the telephone line and the telephone is predominantly communicated through the exchange center over the data transmitter.Type: GrantFiled: October 17, 1979Date of Patent: December 28, 1982Assignees: Mitsubishi Denki Kabushiki Kaisha, Nippon Telegraph and Telephone Public Corp.Inventors: Toshiharu Takatsuki, Ken-ichi Fujiwara, Jutaro Nomura, Shigeru Okamura
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Patent number: 4365254Abstract: Two-color recording paper comprising an ink film and a thermosensitive recording paper which are separably mated together. The ink film has a thin film base and an ink layer of a first hue coated on the film base. The ink layer contains a mixture of a colored material such as dye with a thermoplastic material which is solid at ordinary temperature and becomes fluid at high temperature. The thermosensitive recording paper has a substrate and a coloring layer coated on the substrate. The coloring layer contains a developer which colors in a second hue different from the hue of the ink layer. The ink film and the thermosensitive recording paper are overlapped separably with an ink surface of the ink film and a coloring surface of the thermosensitive recording paper facing each other.Type: GrantFiled: December 28, 1981Date of Patent: December 21, 1982Assignee: Nippon Telegraph and Telephone Public Corp.Inventors: Masaru Ozawa, Yuji Ooba, Toshio Shimizu
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Patent number: 4350541Abstract: A method for fabricating semiconductor devices comprising the steps of: forming on the main surface of a semiconductor substrate an inorganic photoresist layer having a first amorphous layer, which contains Se as a matrix component and includes an impurity for providing one conductivity type and a second silver, or a silver containing layer, formed on the first layer; exposing the inorganic photoresist layer with an exposure pattern; developing the exposed inorganic photoresist layer to form a patterned impurity containing inorganic photoresist layer as an impurity source layer; forming a heat resistive overcoating layer on the main surface of the semiconductor substrate, while covering the impurity source layer; and forming a doped region by diffusing impurity from the impurity source layer into a region of the substrate underlying the impurity source layer.Type: GrantFiled: July 31, 1980Date of Patent: September 21, 1982Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Yoshihiko Mizushima, Akitsu Takeda, Akira Yoshikawa, Osamu Ochi, Tomoko Hisaki
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Patent number: 4346176Abstract: Glass for an optical fiber consists essentially of 10 to 64 mol % of at least one kind of fluoride selected from a first group consisting of CaF.sub.2, SrF.sub.2 and BaF.sub.2 ; 0.5 to 50 mol % of at least one kind of fluoride selected from a second group consisting of YF.sub.3 and fluorides of lanthanide elements; and 30 to 65 mol % of AlF.sub.3.Type: GrantFiled: January 14, 1981Date of Patent: August 24, 1982Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Terutoshi Kanamori, Toyotaka Manabe
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Patent number: 4343023Abstract: m bit data words are converted into one or two n bit (n>m) record words wherein the absolute value of a recording current is less than a predetermined value so as to eliminate a DC component from the recording current. Reproduction is made according to a partial response method thus enabling high linear bit density.Type: GrantFiled: October 22, 1980Date of Patent: August 3, 1982Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Kazutoshi Nishimura, Tadashi Hirono
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Patent number: 4341954Abstract: A photo-electric converting apparatus comprises an array wherein a plurality of photo-electric converting elements are provided, each of which having a semiconductor film layer arranged between an electrode layer and another electrode layer formed on a substrate, and having at least either a rectifying contact or a P-N junction. When the array is irradiated with light under such condition that substantially no bias voltage is applied between the electrode layers of the array, each of the photo-electric converting elements produces forward e.m.f., and forward current flows. A capacitive means in each of the photo-electric converting elements is charged with the forward current, and the capacitive means are discharged successively by scanning pulses, and timed pulse signals are outputted. The present invention discloses further various concrete constructions of the photo-electric converting element and the array thereof with high efficiency of conversion.Type: GrantFiled: February 6, 1980Date of Patent: July 27, 1982Assignees: Nippon Telegraph & Telephone Public Corp., Origin Electric Co., Ltd.Inventors: Yoshihiko Mizushima, Akitsu Takeda, Kazumi Komiya, Masahiro Sakaue, Toshio Ogino, Hideo Itoh, Masayoshi Oka
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Patent number: 4337469Abstract: In an ink jet system printer of the charge amplitude controlling type, it is required to ensure stable printing that viscosity and surface tension of ink liquid supplied to a nozzle is maintained at a constant value. To this end, there is provided a heat generating pipe in an ink supply system and a control circuit for controlling power supply to the heat generating pipe. The viscosity and surface tension of the ink liquid is maintained at a constant value by holding the ink liquid at a predetermined temperature.Type: GrantFiled: December 27, 1977Date of Patent: June 29, 1982Assignees: Nippon Telegraph and Telephone Public Corp., Sharp Kabushiki KaishaInventors: Rikuo Takano, Yuji Sumitomo
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Patent number: 4336597Abstract: A method of measuring the diameter of an electron beam in which the electron beam diameter is measured from the leading edge or trailing edge of a detector signal that is obtained as the mark area formed on the specimen is scanned by the electron beam. This method comprises the following steps: scanning the specimen by the electron beam at least once to find the maximum and minimum values of the detector signal; setting two threshold levels based on the maximum and minimum values; scanning the mark area by the electron beam to measure the time interval during which the level of the detector signal is within the two threshold levels; and calculating the beam diameter.Type: GrantFiled: June 26, 1980Date of Patent: June 22, 1982Assignees: Nippon Telegraph and Telephone Public Corp., Hitachi, Ltd.Inventors: Tsuneo Okubo, Yasuo Kato, Genya Matsuoka
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Patent number: 4334733Abstract: In a glass fiber for optical transmission comprising a primary coat, a thermoplastic resin coat, and a buffer coat between the primary coat and the thermoplastic resin coat, the improvement which comprises said thermoplastic resin being a polyamide having a modulus of elasticity of about 2,000 to 8,000 kg/cm.sup.2 at a temperature in the range of 20 to 23.degree. C.Type: GrantFiled: January 23, 1980Date of Patent: June 15, 1982Assignees: Nippon Telegraph & Telephone Public Corp., Sumitomo Electric Industries, Ltd.Inventors: Mikio Takeshima, Masaaki Kawase, Toru Yamanishi, Masaaki Yoshida
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Patent number: 4331967Abstract: In a field effect semiconductor device comprising a semi-insulator layer composed of a semiconductor material, an N conductivity type active layer made of the same semiconductor material and acting as a channel, spaced cathode and anode electrodes formed on the active layer, the cathode electrode being in ohmic contact with the active layer, and means for applying drive voltage across the cathode and anode electrodes for varying the electrons flowing through the active layer so as to vary output current, a P conductive region is provided beneath the anode electrode and extending through the active layer toward to or penetrating into the semiconductor layer.Type: GrantFiled: January 31, 1980Date of Patent: May 25, 1982Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Katsuhiko Kurumada, Kazuyoshi Asai, Yasunobu Ishii
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Patent number: 4330841Abstract: A logic circuit having at least one asymmetrical quantum interferometric circuit, wherein the logic output states correspond to the voltage state of the asymmetrical quantum interferometric circuit, the asymmetrical quantum interferometric device comprises: a parallel circuit including a first Josephson junction having a threshold current I.sub.j1, a first inductance element having an inductance L.sub.1 and connected in series with the first Josephson junction, a second Josephson junction having a threshold current I.sub.j2, and a second inductance element having an inductance L.sub.Type: GrantFiled: April 16, 1980Date of Patent: May 18, 1982Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Hazime Yamada, Akira Ishida
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Patent number: 4329655Abstract: An adaptive equalization system for compensating the nonlinearities generated in a traveling-wave tube amplifier comprises an equalization circuit connected to the traveling-wave tube amplifier. The equalization circuit has a series circuit having a distortion generator for providing a high order distortion, a variable phase shifter and a variable attenuator for controlling the phase and the amplitude of the output of the distortion generator, and a delay line connected parallel to said series circuit so that the delay time in the delay line is equal to the delay time in that series circuit. A distortion detector is provided at the output of the traveling-wave tube amplifier for detecting the residual distortion in the output signal, and a distortion control circuit is provided for adjusting the variable phase shifter and the variable attenuator so that the residual distortion at the output of the traveling-wave tube amplifier becomes minimum.Type: GrantFiled: January 31, 1980Date of Patent: May 11, 1982Assignee: Nippon Telegraph & Telephone Public Corp.Inventors: Toshio Nojima, Satoshi Ohyama