Patents by Inventor Masatoshi Tobayashi
Masatoshi Tobayashi 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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Publication number: 20240154634Abstract: An amplifier circuit includes: an amplifier connected to an isolating element; a signal midpoint detecting circuit connected in parallel with the isolating element; a bias adding circuit connected in series with the signal midpoint detecting circuit; and an initial voltage value detecting circuit connected to the frame detecting circuit. The initial voltage value detecting circuit holds an initial voltage value of the baseband signal using a signal from the frame detecting circuit, and outputs the initial voltage value to the signal midpoint detecting circuit. The signal midpoint detecting circuit detects a midpoint voltage from the baseband signal and the initial voltage value, and outputs the midpoint voltage to the bias adding circuit. The bias adding circuit adds the midpoint voltage to a bias voltage for biasing the baseband signal. The amplifier amplifies the baseband signal.Type: ApplicationFiled: March 25, 2022Publication date: May 9, 2024Inventors: Tadashi Minotani, Toshiki Kishi, Masatoshi Tobayashi, Yoshikazu Urabe
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Publication number: 20240097948Abstract: An embodiment is a connecting circuit connected to the preceding stage of a transmission circuit and configured to receive a data signal includes an initial voltage value holding circuit, and a terminating load connected in series with the initial voltage value holding circuit. The initial voltage value holding circuit outputs, to the terminating load, an initial voltage value obtained when no data signal is input, and sets both ends of the terminating load at the same potential by a DC component.Type: ApplicationFiled: March 25, 2022Publication date: March 21, 2024Inventors: Tadashi Minotani, Toshiki Kishi, Masatoshi Tobayashi, Yoshikazu Urabe
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Patent number: 10892716Abstract: An amplifier applied to TIA is provided to suppress the noise caused by a current source. An amplifier constituting a transimpedance amplifier includes an inductor element inserted between a current source connected to an input terminal of an amplification stage and a power source voltage line. The current source includes a first transistor in which a base terminal is connected to a current control bias and a collector terminal is connected to the input terminal. The inductor element is inserted between the emitter terminal of the first transistor and the power source voltage line.Type: GrantFiled: July 1, 2016Date of Patent: January 12, 2021Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shinsuke Nakano, Hiroaki Katsurai, Masafumi Nogawa, Shunji Kimura, Masatoshi Tobayashi, Shigehiro Kurita, Masahiro Endo
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Patent number: 10804857Abstract: An amplifier typically exemplified by a TIA is realized that provides an optimal band characteristic, that reduces the possibility of the oscillation, and that achieves a reduced dispersion of the band characteristics. An amplifier for amplifying an electric signal, comprising: a first buffer for amplifying the electric signal; a filter that is connected to an output of the first buffer and that includes a parallel circuit consisting of an inductor and a first capacity; and a second buffer connected to an output of the filter.Type: GrantFiled: May 15, 2018Date of Patent: October 13, 2020Assignees: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, NTT ELECTRONICS CORPORATIONInventors: Masafumi Nogawa, Shinsuke Nakano, Hiroaki Sanjoh, Masatoshi Tobayashi, Yoshikazu Urabe, Masahiro Endo
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Publication number: 20200036344Abstract: An amplifier applied to TIA is provided to suppress the noise caused by a current source. An amplifier constituting a transimpedance amplifier includes an inductor element inserted between a current source connected to an input terminal of an amplification stage and a power source voltage line. The current source includes a first transistor in which a base terminal is connected to a current control bias and a collector terminal is connected to the input terminal. The inductor element is inserted between the emitter terminal of the first transistor and the power source voltage line.Type: ApplicationFiled: July 1, 2016Publication date: January 30, 2020Inventors: Shinsuke Nakano, Hiroaki Katsurai, Masafumi Nogawa, Shunji Kimura, Masatoshi Tobayashi, Shigehiro Kurita, Masahiro Endo
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Publication number: 20190393841Abstract: An amplifier typically exemplified by a TIA is realized that provides an optimal band characteristic, that reduces the possibility of the oscillation, and that achieves a reduced dispersion of the band characteristics. An amplifier for amplifying an electric signal, comprising: a first buffer for amplifying the electric signal; a filter that is connected to an output of the first buffer and that includes a parallel circuit consisting of an inductor and a first capacity; and a second buffer connected to an output of the filter.Type: ApplicationFiled: May 15, 2018Publication date: December 26, 2019Inventors: Masafumi Nogawa, Shinsuke Nakano, Hiroaki Sanjoh, Masatoshi Tobayashi, Yoshikazu Urabe, Masahiro Endo
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Patent number: 9853618Abstract: A transimpedance amplifier circuit (1) includes an amplifier (22) that amplifies a received signal, an automatic gain control (AGC) circuit (2) that controls the amplification gain of the amplifier by a first time constant in accordance with the level of the received signal, and a first selection circuit (25) that selects the first time constant from a plurality of predetermined values. This can simultaneously implement a short time constant of an AGC function necessary to instantaneously respond to a burst signal and a long time constant of the AGC function necessary to obtain a satisfactory bit error rate (BER) characteristic in a continuous signal by an inexpensive and compact circuit arrangement.Type: GrantFiled: September 26, 2014Date of Patent: December 26, 2017Assignees: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, NTT ELECTRONICS CORPORATIONInventors: Hiroshi Koizumi, Masafumi Nogawa, Masatoshi Tobayashi, Masahiro Endo
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Publication number: 20160261246Abstract: A transimpedance amplifier circuit (1) includes an amplifier (22) that amplifies a received signal, an automatic gain control (AGC) circuit (2) that controls the amplification gain of the amplifier by a first time constant in accordance with the level of the received signal, and a first selection circuit (25) that selects the first time constant from a plurality of predetermined values. This can simultaneously implement a short time constant of an AGC function necessary to instantaneously respond to a burst signal and a long time constant of the AGC function necessary to obtain a satisfactory bit error rate (BER) characteristic in a continuous signal by an inexpensive and compact circuit arrangement.Type: ApplicationFiled: September 26, 2014Publication date: September 8, 2016Inventors: Hiroshi KOIZUMI, Masafumi NOGAWA, Masatoshi TOBAYASHI, Masahiro ENDO
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Patent number: 8593201Abstract: In a signal output circuit, an input buffer externally receives a single-phase switching instruction signal to switch a state of the output circuit a shutdown disable state or a shutdown enable state, and converts and outputs the single-phase switching instruction signal into a differential switching instruction signal. A generation control circuit outputs a generation control signal for controlling generation of a control voltage in the control voltage generation circuit based on the differential switching instruction signal. A control voltage generation circuit outputs the control voltage upon changing a value of the control voltage in accordance with a logic of the single-phase switching instruction signal. An output circuit externally receives a differential input signal, outputs a differential output signal upon impedance-converting the differential input signal, and switches between the shutdown disable state and the shutdown enable state of the differential input signal.Type: GrantFiled: June 19, 2012Date of Patent: November 26, 2013Assignees: Nippon Telegraph and Telephone Corporation, NTT Electronics CorporationInventors: Kimikazu Sano, Hiroyuki Fukuyama, Hideyuki Nosaka, Makoto Nakamura, Koichi Murata, Masatoshi Tobayashi, Eisuke Tsuchiya
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Patent number: 8593223Abstract: In an automatic gain control circuit, a peak detection circuit detects and outputs the peak voltage of an output signal from a variable gain circuit. An average value detection/output amplitude setting circuit detects the average value voltage of an output signal from the variable gain circuit, and outputs a calculated voltage. An amplification circuit controls the gain of the variable gain circuit by amplifying the difference between the output voltages of the peak detection circuit and average value detection/output amplitude setting circuit. The number of base-emitter junctions of transistors on a path in the peak detection circuit from input ports which receive output signals from the variable gain circuit to an output port which outputs a voltage to the amplification circuit is equal to the number of base-emitter junctions of transistors on a path in the average value detection/output amplitude setting circuit.Type: GrantFiled: June 19, 2012Date of Patent: November 26, 2013Assignees: Nippon Telegraph and Telephone Corporation, NTT Electronics CorporationInventors: Kimikazu Sano, Hiroyuki Fukuyama, Hideyuki Nosaka, Makoto Nakamura, Koichi Murata, Masatoshi Tobayashi, Yasunobu Inabe, Eisuke Tsuchiya
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Publication number: 20120326782Abstract: In an automatic gain control circuit, a peak detection circuit detects and outputs the peak voltage of an output signal from a variable gain circuit. An average value detection/output amplitude setting circuit detects the average value voltage of an output signal from the variable gain circuit, and outputs a calculated voltage. An amplification circuit controls the gain of the variable gain circuit by amplifying the difference between the output voltages of the peak detection circuit and average value detection/output amplitude setting circuit. The number of base-emitter junctions of transistors on a path in the peak detection circuit from input ports which receive output signals from the variable gain circuit to an output port which outputs a voltage to the amplification circuit is equal to the number of base-emitter junctions of transistors on a path in the average value detection/output amplitude setting circuit.Type: ApplicationFiled: June 19, 2012Publication date: December 27, 2012Inventors: Kimikazu Sano, Hiroyuki Fukuyama, Hideyuki Nosaka, Makoto Nakamura, Koichi Murata, Masatoshi Tobayashi, Yasunobu Inabe, Eisuke Tsuchiya
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Publication number: 20120319766Abstract: In a signal output circuit, an input buffer externally receives a single-phase switching instruction signal to switch a state of the output circuit a shutdown disable state or a shutdown enable state, and converts and outputs the single-phase switching instruction signal into a differential switching instruction signal. A generation control circuit outputs a generation control signal for controlling generation of a control voltage in the control voltage generation circuit based on the differential switching instruction signal. A control voltage generation circuit outputs the control voltage upon changing a value of the control voltage in accordance with a logic of the single-phase switching instruction signal. An output circuit externally receives a differential input signal, outputs a differential output signal upon impedance-converting the differential input signal, and switches between the shutdown disable state and the shutdown enable state of the differential input signal.Type: ApplicationFiled: June 19, 2012Publication date: December 20, 2012Inventors: Kimikazu Sano, Hiroyuki Fukuyama, Hideyuki Nosaka, Makoto Nakamura, Koichi Murata, Masatoshi Tobayashi, Eisuke Tsuchiya
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Patent number: 8144813Abstract: A receiving method according to the present invention adjusts a level of an output voltage signal by switching a gain to be used for converting an inputted current signal to a voltage signal, in a preamplifier. Performing offset compensation on the output voltage signal in an offset compensator, in a post amplifier. Adding a reset signal, whose polarity is made opposite to a polarity of the output voltage signal, to the output voltage signal, in the preamplifier. Detecting the reset signal having added to the output voltage signal, and resetting the offset compensator by use of the detected reset signal, in the post amplifier.Type: GrantFiled: August 2, 2005Date of Patent: March 27, 2012Assignees: Nippon Telegraph and Telephone Corporation, NTT Electronics CorporationInventors: Makoto Nakamura, Yuhki Imai, Masatoshi Tobayashi, Yoshikazu Urabe, Hatsushi Iizuka
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Patent number: 7868701Abstract: A gain switching determination circuit (250) compares/determines a comparative input voltage (Vc) from an inter-stage buffer (230) with a first hysteresis characteristic, and outputs a gain switching signal (SEL) based on the comparison/determination result to first and second transimpedance amplifier core circuits (210, 220), thereby switching the gains of the core circuits. This obviates holding a comparison input voltage with long response time in a level holding circuit for gain switching determination, which allows instantaneous gain switching determination and instantaneous response corresponding to burst data.Type: GrantFiled: August 3, 2005Date of Patent: January 11, 2011Assignees: Nippon Telephone and Telegraph Corporation, NTT Electronics CorporationInventors: Makoto Nakamura, Yohtaro Umeda, Jun Endou, Yuji Akatsu, Yuuki Imai, Masatoshi Tobayashi, Yoshikazu Urabe, Hatsushi Iizuka, Eiji Hyodo
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Publication number: 20080309407Abstract: A gain switching determination circuit (250) compares/determines a comparative input voltage (Vc) from an inter-stage buffer (230) with a first hysteresis characteristic, and outputs a gain switching signal (SEL) based on the comparison/determination result to first and second transimpedance amplifier core circuits (210, 220), thereby switching the gains of the core circuits. This obviates holding a comparison input voltage with long response time in a level holding circuit for gain switching determination, which allows instantaneous gain switching determination and instantaneous response corresponding to burst data.Type: ApplicationFiled: August 3, 2005Publication date: December 18, 2008Applicants: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, NITT ELECTRONICS CORPORATIONInventors: Makoto Nakamura, Yohtaro Umeda, Jun Endou, Yuji Akatsu, Yuuki Imsi, Masatoshi Tobayashi, Yoshikazu Urabe, Hatsushi Iizuka, Eiji Hyodo
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Publication number: 20070292139Abstract: A receiving method according to the present invention adjusts a level of an output voltage signal by switching a gain to be used for converting an inputted current signal to a voltage signal, in a preamplifier. Performing offset compensation on the output voltage signal in an offset compensator, in a post amplifier. Adding a reset signal, whose polarity is made opposite to a polarity of the output voltage signal, to the output voltage signal, in the preamplifier. Detecting the reset signal having added to the output voltage signal, and resetting the offset compensator by use of the detected reset signal, in the post amplifier.Type: ApplicationFiled: August 2, 2005Publication date: December 20, 2007Inventors: Makoto Nakamura, Yuhki Imai, Masatoshi Tobayashi, Yoshikazu Urabe, Hatsushi Iizuka
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Patent number: 7057419Abstract: In a phase sync circuit (40) which extracts a clock signal CK from a data signal D in a random NRZ format, particularly in a phase sync circuit (40) of a dual loop configuration including both a phase comparison circuit (81) and a frequency comparison circuit (10), a phase sync circuit (40) capable of achieving both broadening of the capture range and extraction of a high-quality clock signal without requiring any reference clock signal is provided. A clock signal Ca, another clock signal Cb having a phase delayed by an approximately ¼ period from the clock signal Ca and the data signal D are input to the frequency comparison circuit (10) to output a logical value according to the high-low relationship between the frequency of the clock signal and the bit rate of the data signal D.Type: GrantFiled: July 30, 2002Date of Patent: June 6, 2006Assignee: NTT Electronics Corp.Inventors: Yasuhito Takeo, Nobuhiro Toyoda, Masatoshi Tobayashi
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Patent number: 6888379Abstract: A phase detector circuit that prevents a significant loss of lock during input of CIDs (Consecutive Identical Digits) and has a high linearity of a phase to voltage conversion characteristic around a phase-locked point in an operation of comparing phases of random NRZ signals in a phase. By using the phase detector circuit having a circuit configuration containing a delay circuit and a combination of leapt a multiplier circuit and a subtractor circuit, a capability as the PLL circuit of preventing the significant loss of lock can be realized. In addition, since a duty cycle of a pulse appearing at an output terminal 3 of a multiplier circuit 62 approaches 50% as a phase-locked state is approached, a distortion in the phase to voltage conversion characteristic does not appear, and thus high linearity of the phase to voltage conversion characteristic around thus phase-locked point can be realized.Type: GrantFiled: October 11, 2001Date of Patent: May 3, 2005Assignee: NTT Electronics CorporationInventors: Yasuhiko Takeo, Masatoshi Tobayashi, Masaki Hirose, Yukio Akazawa
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Publication number: 20050008112Abstract: In a phase sync circuit (40) which extracts a clock signal CK from a data signal D in a random NRZ format, particularly in a phase sync circuit (40) of a dual loop configuration including both a phase comparison circuit (81) and a frequency comparison circuit (10), a phase sync circuit (40) capable of achieving both broadening of the capture range and extraction of a high-quality clock signal without requiring any reference clock signal is provided. A clock signal Ca, another clock signal Cb having a phase delayed by an approximately ¼ period from the clock signal Ca and the data signal D are input to the frequency comparison circuit (10) to output a logical value according to the high-low relationship between the frequency of the clock signal and the bit rate of the data signal D.Type: ApplicationFiled: July 30, 2002Publication date: January 13, 2005Inventors: Yasuhito Takeo, Nobuhiro Toyoda, Masatoshi Tobayashi
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Publication number: 20030020514Abstract: To provide a phase detector circuit that prevents a significant loss of lock during input of CIDs (Consecutive Identical Digits) and have a high linearity of a phase to voltage conversion characteristic around phase-locked point in an operation of comparing phases of random NRZ signals in a phase.Type: ApplicationFiled: July 16, 2002Publication date: January 30, 2003Inventors: Yasuhiko Takeo, Masatoshi Tobayashi, Masaki Hirose, Yukio Akazawa