Patents by Inventor Masahito Tomizawa
Masahito Tomizawa 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: 20200028767Abstract: A plurality of error correction circuits corrects errors of the data transmitted through the plurality of transmission lines. A combining portion combines the plurality of transmission lines to the plurality of error correction circuits. The plurality of transmission lines includes a first transmission line, and a second transmission line having a lower transmission characteristic than the first transmission line. The plurality of error correction circuits includes a first and a second error correction circuit having lower error correction capability and power consumption than the first error correction circuit. The combining portion uses a function to combine a plurality of error correction circuits with one transmission path, combines the first transmission line with the second error correction circuit at a higher rate than the first error correction circuit, and combines the second transmission line with the first error correction circuit at a higher rate than the second error correction circuit.Type: ApplicationFiled: December 15, 2017Publication date: January 23, 2020Applicants: NTT Electronics Corporation, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Mitsuteru YOSHIDA, Yasuyuki ENDO, Etsushi YAMAZAKI, Katsuichi OYAMA, Yasuharu ONUMA, Masahito TOMIZAWA
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Patent number: 10523335Abstract: Fourier transform is performed on a reception signal to obtain a first calculation value. Fourier transform is performed on a known signal to obtain a second calculation value. The first calculation value is divided by the second calculation value to obtain a third calculation value. Inverse Fourier transform is performed on the third calculation value to obtain a fourth calculation value. A maximum value of an amplitude of the fourth calculation value and a sample point at which the maximum value is obtained are detected. The position of the known signal in the reception signal is detected from the sample point at which the maximum value is obtained.Type: GrantFiled: June 21, 2017Date of Patent: December 31, 2019Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yasuharu Onuma, Etsushi Yamazaki, Tomohiro Takamuku, Masahiro Tachibana, Mitsuteru Yoshida, Masahito Tomizawa, Seiji Okamoto
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Patent number: 10419127Abstract: A symbol phase difference compensating portion (6) calculates a first phase difference which is a phase difference between a known pattern extracted from a received signal and a true value of the known pattern and performs phase compensation for the received signal based on the first phase difference. A tentative determination portion (12) tentatively determines an output signal of the symbol phase difference compensating portion (6) to acquire an estimated value of a phase. A first phase difference acquiring portion (13) acquires a second phase difference which is a phase difference between a phase of the output signal and the estimated value of the phase acquired by the tentative determination portion (12). A first phase difference compensating portion (14) performs phase compensation for the output signal based on the second phase difference.Type: GrantFiled: April 13, 2017Date of Patent: September 17, 2019Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Etsushi Yamazaki, Hiroyukl Nouchi, Yasuharu Onuma, Tomohiro Takamuku, Katsuichi Oyama, Kazuhito Takei, Masahito Tomizawa, Yoshiaki Kisaka, Mltsuteru Yoshida, Masanori Nakamura
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Patent number: 10374718Abstract: An I component compensation unit calculates an I component in which a distortion has been compensated, by forming a first polynomial expressing the distortion of the I component based on an I component and a Q component of a quadrature modulation signal and multiplying each term of the first polynomial by a first coefficient. A Q component compensation unit calculates a Q component in which a distortion has been compensated, by forming a second polynomial expressing the distortion of the Q component based on the I component and the Q component of the quadrature modulation signal and multiplying each term of the second polynomial by a second coefficient. A coefficient calculation unit calculates the first and second coefficients by comparing outputs of the I component compensation unit and the Q component compensation unit and a known signal.Type: GrantFiled: June 21, 2017Date of Patent: August 6, 2019Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yasuharu Onuma, Etsushi Yamazaki, Hiroyuki Nouchi, Tomohiro Takamuku, Katsuichi Oyama, Kazuhito Takei, Masanori Nakamura, Mitsuteru Yoshida, Masahito Tomizawa
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Publication number: 20190165868Abstract: Fourier transform is performed on a reception signal to obtain a first calculation value. Fourier transform is performed on a known signal to obtain a second calculation value. The first calculation value is divided by the second calculation value to obtain a third calculation value. Inverse Fourier transform is performed on the third calculation value to obtain a fourth calculation value. A maximum value of an amplitude of the fourth calculation value and a sample point at which the maximum value is obtained are detected. The position of the known signal in the reception signal is detected from the sample point at which the maximum value is obtained.Type: ApplicationFiled: June 21, 2017Publication date: May 30, 2019Inventors: Yasuharu ONUMA, Etsushi YAMAZAKI, Tomohiro TAKAMUKU, Masahiro TACHIBANA, Mitsuteru YOSHIDA, Masahito TOMIZAWA, Seiji OKAMOTO
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Patent number: 10305675Abstract: An FIR filter convolutes sampled data obtained by sampling a reception signal with tap coefficients. A phase difference detector detects a phase difference between a synchronization timing of a signal waveform estimated from an output signal of the FIR filter and a sampling timing of the output signal. A tap coefficient adjuster adjusts the tap coefficients so as to reduce the phase difference detected by the phase difference detector and causes the sampling timing of the output signal of the FIR filter to track the synchronization timing.Type: GrantFiled: January 16, 2017Date of Patent: May 28, 2019Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yasuharu Onuma, Masahiro Tachibana, Etsushi Yamazaki, Kazuhito Takei, Yuki Yoshida, Masayuki Ikeda, Yoshiaki Kisaka, Masahito Tomizawa
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Publication number: 20190132051Abstract: An I component compensation unit calculates an I component in which a distortion has been compensated, by forming a first polynomial expressing the distortion of the I component based on an I component and a Q component of a quadrature modulation signal and multiplying each term of the first polynomial by a first coefficient. A Q component compensation unit calculates a Q component in which a distortion has been compensated, by forming a second polynomial expressing the distortion of the Q component based on the I component and the Q component of the quadrature modulation signal and multiplying each term of the second polynomial by a second coefficient. A coefficient calculation unit calculates the first and second coefficients by comparing outputs of the I component compensation unit and the Q component compensation unit and a known signal.Type: ApplicationFiled: June 21, 2017Publication date: May 2, 2019Inventors: Yasuharu ONUMA, Etsushi YAMAZAKI, Hiroyuki NOUCHI, Tomohiro TAKAMUKU, Katsuichi OYAMA, Kazuhito TAKEI, Masanori NAKAMURA, Mitsuteru YOSHIDA, Masahito TOMIZAWA
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Publication number: 20190074903Abstract: A reception circuit includes a first adaptive compensator compensating distortion of a received signal. An adaptive compensation coefficient calculator includes a known-signal detector detecting first and second known-signals from the received signal, a second adaptive compensator compensating distortion of the received signal, a tap coefficient initial value calculator calculating an initial value of a tap coefficient of the second adaptive compensator by comparing the first known-signal with its true value, a first phase shift compensator compensating phase shift of an output of the second adaptive compensator using the second known-signal, and a tap coefficient calculator calculating tap coefficients of the first and second adaptive compensators by comparing at least one of the first and second known-signals compensated by the second adaptive compensator and the first phase shift compensator with its true value.Type: ApplicationFiled: May 26, 2017Publication date: March 7, 2019Inventors: Tomohiro TAKAMUKU, Etsushi YAMAZAKI, Katsuichi OYAMA, Yasuharu ONUMA, Kazuhito TAKEI, Masanori NAKAMURA, Mitsuteru YOSHIDA, Masahito TOMIZAWA, Yoshiaki KISAKA
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Publication number: 20190074909Abstract: A symbol phase difference compensating portion (6) calculates a first phase difference which is a phase difference between a known pattern extracted from a received signal and a true value of the known pattern and performs phase compensation for the received signal based on the first phase difference. A tentative determination portion (12) tentatively determines an output signal of the symbol phase difference compensating portion (6) to acquire an estimated value of a phase. A first phase difference acquiring portion (13) acquires a second phase difference which is a phase difference between a phase of the output signal and the estimated value of the phase acquired by the tentative determination portion (12). A first phase difference compensating portion (14) performs phase compensation for the output signal based on the second phase difference.Type: ApplicationFiled: April 13, 2017Publication date: March 7, 2019Inventors: Etsushi YAMAZAKI, Hiroyukl NOUCHI, Yasuharu ONUMA, Tomohiro TAKAMUKU, Katsuichi OYAMA, Kazuhito TAKEI, Masahito TOMIZAWA, Yoshiaki KISAKA, Mltsuteru YOSHIDA, Masanori NAKAMURA
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Patent number: 10171173Abstract: An optical signal transmission apparatus includes a modulation unit which modulates a transmission signal, a training signal sequence generation unit which generates a plurality of signal sequences having power concentrated in a plurality of different frequency bands, at least one of an amplitude and a phase of the plurality of signal sequences being modulated, as a training signal sequence, a signal multiplexing unit which appends the training signal sequence to the transmission signal, and an electro-optical conversion unit which converts a signal sequence obtained by appending the training signal sequence to the transmission signal into an optical signal and transmits the optical signal.Type: GrantFiled: March 17, 2015Date of Patent: January 1, 2019Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Seiji Okamoto, Koichi Ishihara, Etsushi Yamazaki, Mitsuteru Yoshida, Tomoyoshi Kataoka, Kazushige Yonenaga, Yoshiaki Kisaka, Masanori Nakamura, Masahito Tomizawa
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Patent number: 10128818Abstract: A parallel transfer rate converter inputs first parallel data with number of samples being S1 pieces in synchronism with a first clock, and outputs second parallel data with number of samples being S2=S1×(m/p) pieces (p is an integer equal to or larger than 1) in synchronism with a second clock having a frequency which is p/m times of a frequency of the first clock. A convolution operation device inputs the second parallel data in synchronism with the second clock, generates third parallel data with number of samples being S3=S2×(n/m) pieces (S3 is an integer equal to or larger than 1) by executing a convolution operation with a coefficient indicating a transmission characteristic to the second parallel data, and outputs the third parallel data in synchronism with the second clock.Type: GrantFiled: January 16, 2017Date of Patent: November 13, 2018Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yasuharu Onuma, Etsushi Yamazaki, Kazuhito Takei, Osamu Ishida, Kengo Horikoshi, Mitsuteru Yoshida, Yoshiaki Kisaka, Masahito Tomizawa
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Patent number: 10122462Abstract: A transport apparatus includes: a client signal transceiving unit which transceives a client signal; a line signal transceiving unit which performs electric-optic conversion on a line signal to be transmitted, transmits an optical line signal, performs optic-electric conversion on a received line signal, and outputs an electrical line signal; and a plurality of signal processing units which perform signal processing on the client signal to generate the line signal to be transmitted and perform signal processing on the electrical line signal to generate the client signal.Type: GrantFiled: November 19, 2014Date of Patent: November 6, 2018Assignee: Nippon Telegraph And Telephone CorporationInventors: Takuya Ohara, Kei Kitamura, Yoshiaki Kisaka, Shigeki Aisawa, Masahiro Suzuki, Etsushi Yamazaki, Tomoyoshi Kataoka, Masahito Tomizawa, Yoshiaki Yamada, Mitsuhiro Teshima, Akira Hirano
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Patent number: 10122465Abstract: Signal processing sections selectively switch modulation/demodulation in low-efficiency modulation system and modulation/demodulation in high-efficiency modulation system, and perform digital signal processing. Parallel-side interfaces of input/output interface sections are electrically connected to the signal processing section. A serial-side interface of the input/output interface section is electrically connected to a serial-side interface of the input/output interface section. A selection section electrically connects a parallel-side interface of the input/output interface section to the signal processing section when the low-efficiency modulation system is selected, and electrically connects the parallel-side interface of the input/output interface section to a parallel-side interface of the input/output interface section when the high-efficiency modulation system is selected.Type: GrantFiled: September 5, 2016Date of Patent: November 6, 2018Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Osamu Ishida, Etsushi Yamazaki, Kazuhito Takei, Masahito Tomizawa, Hideki Nishizawa
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Publication number: 20180302211Abstract: An FIR filter convolutes sampled data obtained by sampling a reception signal with tap coefficients. A phase difference detector detects a phase difference between a synchronization timing of a signal waveform estimated from an output signal of the FIR filter and a sampling timing of the output signal. A tap coefficient adjuster adjusts the tap coefficients so as to reduce the phase difference detected by the phase difference detector and causes the sampling timing of the output signal of the FIR filter to track the synchronization timing.Type: ApplicationFiled: January 16, 2017Publication date: October 18, 2018Inventors: Yasuharu ONUMA, Masahiro TACHIBANA, Etsushi YAMAZAKI, Kazuhito TAKEI, Yuki YOSHIDA, Masayuki IKEDA, Yoshiaki KISAKA, Masahito TOMIZAWA
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Patent number: 10038507Abstract: An increase in circuit scale is suppressed and a phase variation caused in a transmission path or the like is compensated for.Type: GrantFiled: February 13, 2014Date of Patent: July 31, 2018Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Mitsuteru Yoshida, Etsushi Yamazaki, Seiji Okamoto, Hiroyuki Uzawa, Kengo Horikoshi, Koichi Ishihara, Takayuki Kobayashi, Yoshiaki Kisaka, Masahito Tomizawa, Naoki Fujiwara, Tomoyoshi Kataoka, Kazushige Yonenaga
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Publication number: 20180175830Abstract: A parallel transfer rate converter inputs first parallel data with number of samples being S1 pieces in synchronism with a first clock, and outputs second parallel data with number of samples being S2=S1×(m/p) pieces (p is an integer equal to or larger than 1) in synchronism with a second clock having a frequency which is p/m times of a frequency of the first clock. A convolution operation device inputs the second parallel data in synchronism with the second clock, generates third parallel data with number of samples being S3=S2×(n/m) pieces (S3 is an integer equal to or larger than 1) by executing a convolution operation with a coefficient indicating a transmission characteristic to the second parallel data, and outputs the third parallel data in synchronism with the second clock.Type: ApplicationFiled: January 16, 2017Publication date: June 21, 2018Inventors: Yasuharu ONUMA, Etsushi YAMAZAKI, Kazuhito TAKEI, Osamu ISHIDA, Kengo HORIKOSHI, Mitsuteru YOSHIDA, Yoshiaki KISAKA, Masahito TOMIZAWA
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Publication number: 20180152247Abstract: Signal processing sections selectively switch modulation/demodulation in low-efficiency modulation system and modulation/demodulation in high-efficiency modulation system, and perform digital signal processing. Parallel-side interfaces of input/output interface sections are electrically connected to the signal processing section. A serial-side interface of the input/output interface section is electrically connected to a serial-side interface of the input/output interface section. A selection section electrically connects a parallel-side interface of the input/output interface section to the signal processing section when the low-efficiency modulation system is selected, and electrically connects the parallel-side interface of the input/output interface section to a parallel-side interface of the input/output interface section when the high-efficiency modulation system is selected.Type: ApplicationFiled: September 5, 2016Publication date: May 31, 2018Inventors: Osamu ISHIDA, Etsushi YAMAZAKI, Kazuhito TAKEI, Masahito TOMIZAWA, Hideki NISHIZAWA
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Patent number: 9698932Abstract: An optical transmission and reception system includes a transmitter and receiver. The transmitter differentially encodes control information to generate a differentially coded signal; uses the differentially coded signal to modulate a signal sequence in which electricity concentrates at a particular frequency; applies time-division multiplexing on the modulated signal sequence and a primary signal in one of two polarized wave components, and applies time-division multiplexing on the other polarized wave components and the signal sequence itself; and polarization-multiplexes the both of the time-division multiplexed polarized waves into an optical signal; and transmits the optical signal to the receiver.Type: GrantFiled: March 14, 2014Date of Patent: July 4, 2017Assignee: Nippon Telegraph and Telephone CorporationInventors: Yoshiaki Kisaka, Koichi Ishihara, Masahito Tomizawa, Etsushi Yamazaki
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Patent number: 9667350Abstract: The optical receiving device with phase compensation apparatus uses coherent opto-electric conversion and is designed for receiving phase- or quadrature-amplitude-modulated optical signals. The phase compensation apparatus includes following elements: a carrier-phase estimation unit that estimates carrier phase errors in a received symbol string; a gain adjustment unit that adjusts weighting of each symbols in phase error evaluation performed in the carrier-phase adjustment unit; a phase-cycle-slip reduction unit with a phase-cycle-slip detector using statistical processing performed on the output symbols from the carrier-phase estimation unit; and a phase compensation circuit that compensates carrier phase errors of the received signal using an output from the carrier phase estimation unit.Type: GrantFiled: January 24, 2014Date of Patent: May 30, 2017Assignee: Nippon Telegraph And Telephone CorporationInventors: Kengo Horikoshi, Kohki Shibahara, Etsushi Yamazaki, Mitsuteru Yoshida, Koichi Ishihara, Takayuki Kobayashi, Yoshiaki Kisaka, Takuya Ohara, Masahito Tomizawa, Tomoyoshi Kataoka
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Publication number: 20170111116Abstract: A transport apparatus includes: a client signal transceiving unit which transceives a client signal; a line signal transceiving unit which performs electric-optic conversion on a line signal to be transmitted, transmits an optical line signal, performs optic-electric conversion on a received line signal, and outputs an electrical line signal; and a plurality of signal processing units which perform signal processing on the client signal to generate the line signal to be transmitted and perform signal processing on the electrical line signal to generate the client signal.Type: ApplicationFiled: November 19, 2014Publication date: April 20, 2017Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Takuya OHARA, Kei KITAMURA, Yoshiaki KISAKA, Shigeki AISAWA, Masahiro SUZUKI, Etsushi YAMAZAKI, Tomoyoshi KATAOKA, Masahito TOMIZAWA, Yoshiaki YAMADA, Mitsuhiro TESHIMA, Akira HIRANO