Patents by Inventor Takeshi Ihara
Takeshi Ihara has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6498670Abstract: It is aimed at providing an optical receiving apparatus and an optical receiving method, which can assuredly receive and process signal lights having different transmission rates, by a simple and single device. To this end, the signal light received by the present optical receiving apparatus is converted into an electric signal by a light receiving element and thereafter sent to an equalizing amplifier whereby the signal is amplified. The transmission rate of this received signal is detected by a transmission rate detecting part, and a band of the equalizing amplifier is optimally controlled by an equalizing band controlling part, corresponding to the detected transmission rate. In case of adopting a PLL (phase-locked loop) circuit as a clock generating circuit, there is also controlled a band of a loop filter corresponding to the transmission rate detected by the transmission rate detecting part.Type: GrantFiled: July 21, 1998Date of Patent: December 24, 2002Assignee: Fujitsu LimitedInventors: Katsuya Yamashita, Takeshi Ihara, Hiroshi Hamano
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Publication number: 20020067532Abstract: It is aimed at providing an optical receiving apparatus and an optical receiving method, which can assuredly receive and process signal lights having different transmission rates, by a simple and single device. To this end, the signal light received by the present optical receiving apparatus is converted into an electric signal by a light receiving element and thereafter sent to an equalizing amplifier whereby the signal is amplified. The transmission rate of this received signal is detected by a transmission rate detecting part, and a band of the equalizing amplifier is optimally controlled by an equalizing band controlling part, corresponding to the detected transmission rate. In case of adopting a PLL (phase-locked loop) circuit as a clock generating circuit, there is also controlled a band of a loop filter corresponding to the transmission rate detected by the transmission rate detecting part.Type: ApplicationFiled: July 21, 1998Publication date: June 6, 2002Inventors: KATSUYA YAMASHITA, TAKESHI IHARA, HIROSHI HAMANO
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Patent number: 6204949Abstract: A method for extracting a timing signal produces a data signal from a first portion of an optical signal, extracts a timing signal from a second portion of the optical signal and adds dispersion compensation to at least one of the first and second portions of the optical signal to thereby control the amount of total dispersion in the second portion of the optical signal to be substantially different from the amount of total dispersion in the first portion of the optical signal. The timing signal extracting device uses a signal reproduction circuit to produce the data signal, a signal extraction circuit to extract the timing signal and a chromatic dispersion control apparatus to add dispersion compensation. The optical signal may be modulated by a data signal having a bit rate of X bits/second and the extracted timing signal may have a frequency of X hertz. The signal extraction circuit may be used with a phase locked loop.Type: GrantFiled: April 9, 1998Date of Patent: March 20, 2001Assignee: Fujitsu LimitedInventors: George Ishikawa, Hiroki Ooi, Takeshi Ihara
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Patent number: 6068697Abstract: A polysaccharide derivative prepared by replacing all or part of the hydroxyl hydrogen atoms of a polysaccharide or polysaccharide derivative by (A) a hydrophobic substituent having a C.sub.8 -C.sub.43 hydrocarbon chain as the partial structure and (B) an ionic hydrophilic substituent having at least one member selected from the group consisting of sulfonic, carboxyl phosphoric, and sulfate groups and salts thereof as the partial structure, wherein the average degree of replacement by the substituent (A) is 0.0001 or above but below 0.001 per constituent monosaccharide residue as determined by Zeisel's method or the diazomethane method and that by the substituent (B) is 0.01 to 2.0 per constituent monosaccharide residue as determined by colloidal titration. This polysaccharide derivative is useful as the admixture for hydraulic materials and can give stable hydraulic compositions excellent in dispersion.Type: GrantFiled: July 14, 1998Date of Patent: May 30, 2000Assignee: Kao CorporationInventors: Hotaka Yamamuro, Takeshi Ihara, Tomohito Kitsuki, Tetsuya Miyajima, Fujio Yamato, Makoto Kohama
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Patent number: 5999289Abstract: Waveform degradation due to chromatic dispersion of an optical fiber is detected and compensated for. A waveform detector detects a change in waveform, based on the ratio between the powers of a plurality of frequency components or on peak or duty detection, and the frequency bandwidth of an equalizing amplifier or the chromatic dispersion of an optical fiber is controlled based on the result of the detection.Type: GrantFiled: March 6, 1998Date of Patent: December 7, 1999Assignee: Fujitsu LimitedInventors: Takeshi Ihara, Yoichi Oikawa
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Patent number: 5963110Abstract: An equalizing filter with an optimized frequency response and improved reliability and quality, for equalizing a reception signal so as to regain its original waveform. The equalizing filter comprises a low-pass filter and a high-frequency booster circuit. With its limited passband, the low-pass filter rejects the noise components contained in the signal being processed. The high-frequency booster circuit has such a frequency response that exhibits a stepwise gain increase at high frequencies. Those two elements, composed of reliable passive components, are coupled in series to provide a combined frequency response that is optimized for the design of highly sensitive optical receivers. As integral part of the high-frequency booster circuit, the equalizing filter employs an inductor made of a bonding wire.Type: GrantFiled: March 3, 1998Date of Patent: October 5, 1999Assignee: Fujitsu LimitedInventors: Takeshi Ihara, Hiroshi Hamano
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Patent number: 5872272Abstract: The present invention relates to polyvalent metal salts of a phosphoric diester represented by formula (1) and organo(poly)siloxanes modified with a polyvalent metal salt of a phosphoric diester having the structural units represented by formulae (9) and (10): ##STR1## wherein R.sup.1 represents a C1 to C20 linear or branched alkyl group, R.sup.2 and R.sup.4 are the same or different and independently represent a C2 to C3 linear or branched alkylene group, R.sup.3 represents a C3 to C20 linear or C5 to C20 branched alkylene group, A represents a group --COO-- or --O--, x and y are the same or different from each other and independently represent an integer of 0 to 10, L represents a C1 to C40 linear or branched alkyl group or a group, R.sup.1 --(OR.sup.2).sub.x --A--R.sup.3 (OR.sup.4).sub.y -- wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, A, x and y have the same meaning as defined herein before, M represents a divalent or polyvalent metal atom, and m represents the same value as the valence of M.Type: GrantFiled: June 15, 1995Date of Patent: February 16, 1999Assignee: Kao CorporationInventors: Shinji Yano, Junichi Fukasawa, Hironori Kawasaki, Munehisa Okutsu, Takeshi Ihara, Katsumi Kita, Yoshiaki Fujikura, Akira Akaogi
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Patent number: 5565601Abstract: Phosphoric esters (mono-, di- or triester) is useful as, for example, a cleaner, an emulsifier, an antistatic agent, metal-chelating agent and a lubricant for fibers. It is produced at a high yield while completely trapping the hydrogen chloride gas formed as a by-product. The reaction between a phosphorus oxyhalide and an organic hydroxyl compound to produce a phosphoric ester is effected in the presence of a metal salt of an acid having a pKa of from -5 to 13.Type: GrantFiled: July 3, 1995Date of Patent: October 15, 1996Assignee: Kao CorporationInventors: Takeshi Ihara, Shinji Yano, Katsumi Kita
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Patent number: 5530084Abstract: The present invention relates to organo(poly)siloxanes modified by phosphates (including alkali metal salts thereof or the like) suitable as a component of cosmetics, and to a process for the manufacture of organo(poly)siloxanes modified by phosphates (including alkali metal salts thereof or the like) comprising reacting an organo(poly)siloxane having a group HO--(R.sup.4 O).sub.q --R.sup.5' --OR.sup.6).sub.r -- in its molecular chain, wherein R.sup.4 -R.sup.6 are alkylene groups, with an oxyhalogenated phosphorus; and further reacting it with an alkaline solution. These phosphate-modified organo(poly)siloxanes can stably emulsify silicone oils commonly used as cosmetic raw materials, irrespective of temperatures, and exhibit excellent compatibility with polar components and good foaming capability, so that they are suitable as a component of cosmetics such as skin cosmetics, skin detergents, hair cosmetics, hair detergents, and the like.Type: GrantFiled: March 6, 1995Date of Patent: June 25, 1996Assignee: Kao CorporationInventors: Takeshi Ihara, Shinji Yano, Katsumi Kita, Yoshiaki Fujikura
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Patent number: 5510745Abstract: A high speed electronic circuit has a cascode circuit configuration and is provided with a bias current source (CS.sub.0) between an emitter and a base of a load transistor (Q) in the cascode circuit configuration for compensating a base-emitter voltage (V.sub.BE) of the transistor to eliminate an adverse effect of charging and discharging at a stray capacitor (C) which can be connected between the base and the emitter of the transistor. The high speed electronic circuit can be applied to an; circuit, a level shift circuit, a level shift discrimination circuit, a signal distribution circuit, a signal synthesization circuit and a frequency band control circuit.Type: GrantFiled: December 21, 1993Date of Patent: April 23, 1996Assignee: Fujitsu LimitedInventors: Hiroshi Hamano, Izumi Amemiya, Takuji Yamamoto, Hiroo Kitasagami, Takeshi Ihara
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Patent number: 5506542Abstract: A filter circuit and a filter integrated circuit capable of being used in a high frequency band includes a first resistor R.sub.1 connected between an input signal source and an emitter of a common-base transistor TR.sub.1, a first capacitor C.sub.1 connected between said input signal source and a reference voltage point, a second capacitor C.sub.2 connected between said input signal source and a collector of the common-base transistor TR.sub.1, and a second resistor R.sub.2 connected between the collector of the common-base transistor and the reference voltage point. Thus, a low-pass filter which operates in a high frequency band and suppresses the influence of characteristic parameters over the filter characteristic can be constructed.Type: GrantFiled: November 12, 1993Date of Patent: April 9, 1996Assignee: Fujitsu LimitedInventors: Hiroshi Hamano, Izumi Amemiya, Yoichi Oikawa, Takuji Yamamoto, Takeshi Ihara, Yoshinori Nishizawa
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Patent number: 5293087Abstract: A filter circuit and a filter integrated circuit capable of being used in a high frequency band comprises a first resistor R.sub.1 connected between an input signal source and an emitter of a common-base transistor TR.sub.1, a first capacitor C.sub.1 connected between said input signal source and a reference voltage point, a second capacitor C.sub.2 connected between said input signal source and a collector of the common-base transistor TR.sub.1, and a second resistor R.sub.2 connected between the collector of the common-base transistor and the reference voltage point. Thus, a low-pass filter which operates in a high frequency band and suppresses the influence of characteristic parameters over the filter characteristic can be constructed.Type: GrantFiled: October 19, 1992Date of Patent: March 8, 1994Assignee: Fujitsu LimitedInventors: Hiroshi Hamano, Izumi Amemiya, Yoichi Oikawa, Takuji Yamamoto, Takeshi Ihara, Yoshinori Nishizawa
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Patent number: 5206986Abstract: An electronic circuit package which includes first and second conductive metal members and a circuit board held between the first and second metal members and having a cutout in which an electronic circuit part is accommodated and a process of producing such electronic circuit package are disclosed. With the electronic circuit package, deterioration of a high speed characteristic of an electronic circuit part accommodated in the package is minimized, and accordingly, when the electronic circuit package is applied to an IC for very high speed optical communications for use with an optical repeater or the like, a very high speed system can be realized. By assembling the components in accordance with a predetermined order, facility in process of production and improvement in reliability of products are attained.Type: GrantFiled: June 23, 1992Date of Patent: May 4, 1993Assignee: Fujitsu LimitedInventors: Yasunari Arai, Hiroshi Hamano, Izumi Amemiya, Takuji Yamamoto, Takeshi Ihara
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Patent number: 5150280Abstract: An electronic circuit package which includes first and second conductive metal members and a circuit board held between the first and second metal members and having a cutout in which an electronic circuit part is accommodated and a process of producing such electronic circuit package are disclosed. With the electronic circuit package, deterioration of a high speed characteristic of an electronic circuit part accommodated in the package is minimized, and accordingly, when the electronic circuit package is applied to an IC for very high speed optical communications for use with an optical repeater or the like, a very high speed system can be realized. By assembling the components in accordance with a predetermined order, facility in process of production and improvement in reliability of products are attained.Type: GrantFiled: August 8, 1990Date of Patent: September 22, 1992Assignee: Fujitsu LimitedInventors: Yasunari Arai, Hiroshi Hamano, Izumi Amemiya, Takuji Yamamoto, Takeshi Ihara
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Patent number: 5113151Abstract: Disclosed is an equalizing and amplifying circuit in an optical signal receiving apparatus comprising a preamplifier circuit having an input terminal connected to the output of a light receiving element. The preamplifier circuit amplifies the electrical signal from the light receiving element and outputs an amplified signal. An automatic gain control circuit is connected to the output of the preamplifier circuit. The preamplifier circuit comprises a transistor having a common-base, a current source connected to the emitter of the transistor for supplying a bias current to the transistor, and a load resistor connected to the collector of the transistor. The emitter of the transistor is connected to the input terminal, and the collector of the transistor is connected to the output terminal. A negative influence caused by mounting the circuit on a package is avoided and the circuit operates stably in a high frequency range.Type: GrantFiled: July 19, 1990Date of Patent: May 12, 1992Assignee: Fujitsu LimitedInventors: Takuji Yamamoto, Hiroshi Hamano, Izumi Amemiya, Yasunari Arai, Takeshi Ihara
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Patent number: 5066877Abstract: A data delay circuit includes a first transistor, and a second transistor having a base, an emitter and a collector. Input data is applied to the bases of the first and second transistors. A constant-current source is coupled between the emitters of the first and second transistors and a negative power source. A capacitor is connected between the collector of the first transistor and the collector of the second transistor. The data delay circuit further includes a third transistor and a fourth transistor. The emitters of the third and fourth transistors are connected to the collectors of the first and second transistors, respectively. The bases of the third and fourth transistors are provided with control data having a polarity opposite to that of the input data and having an adjusted amplitude level corresponding to a desired delay time to be given the input data. First and second load resistors are respectively coupled to the collectors of the third and fourth transistors through a positive power source.Type: GrantFiled: February 28, 1991Date of Patent: November 19, 1991Assignee: Fujitsu LimitedInventors: Hiroshi Hamano, Izumi Amemiya, Takuji Yamamoto, Yasunari Arai, Takeshi Ihara