Patents by Inventor Katsuichi Oyama
Katsuichi Oyama 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: 11611395Abstract: First compensation circuitry includes a first digital filter compensating a phase difference between a phase of a symbol of a received signal and a sampling timing, and first filter coefficient calculation circuitry calculating a filter coefficient of the first digital filter as a first filter coefficient. Second filter coefficient calculation circuitry calculates, as a second filter coefficient, a filter coefficient for adaptive equalization that compensates distortion due to temporally changing polarization dispersion, based on an output of the first digital filter. Coefficient combination circuitry combines the first filter coefficient and the second filter coefficient. Second compensation circuitry includes a second digital filter which uses a filter coefficient combined by the coefficient combination circuitry and performs a compensation of the phase difference between the phase of the symbol of the received signal and the sampling timing, and a process of the adaptive equalization at the same time.Type: GrantFiled: October 7, 2019Date of Patent: March 21, 2023Assignee: NTT ELECTRONICS CORPORATIONInventors: Tomohiro Takamuku, Mitsuteru Yoshida, Tsutomu Takeya, Kazuhito Takei, Katsuichi Oyama, Tomoharu Semboku
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Patent number: 11329764Abstract: An error correction device includes a first correction unit which performs error correction decoding of data by a repetitive operation, having a full operation state in which the error correction decoding is repeated until convergence is obtained and a save operation state in which the number of times of the repetitive operation is restricted to a predetermined number. An error information estimation unit estimates an input error rate or an output error rate of the first correction unit using a decoding result of the first correction unit, and a control unit which controls transition between the full operation state and the save operation state based on at least one piece of information of the input error rate, the output error rate, and an operation time of the first correction unit. It is thus possible to provide an error correction device that can improve a transmission characteristic while suppressing power consumption.Type: GrantFiled: December 20, 2018Date of Patent: May 10, 2022Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Fumiaki Nakagawa, Yasuharu Onuma, Katsuichi Oyama, Yasuyuki Endoh, Etsushi Yamazaki, Yoshiaki Kisaka, Masahito Tomizawa
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Patent number: 11323238Abstract: A frame synchronization apparatus (10) according to this invention includes a multiplication unit (11) configured to multiply a received signal by an inverse complex number of a predetermined synchronization pattern with respect to a predetermined signal point on a complex space diagram for each of a plurality of symbols of the received signal, an addition average unit (12) configured to perform addition averaging of outputs from the multiplication unit for the plurality of symbols of the received signal, and a synchronization determination unit (13) configured to perform coincidence determination of whether an output from the addition average unit (12) falls within a predetermined coincidence determination range of the predetermined signal point, and determine a synchronization state of the frame synchronization based on a result of the coincidence determination.Type: GrantFiled: June 6, 2019Date of Patent: May 3, 2022Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Mitsuteru Yoshida, Yasuyuki Endoh, Katsuichi Oyama, Masayuki Ikeda, Tsutomu Takeya, Etsushi Yamazaki, Yoshiaki Kisaka, Masahito Tomizawa
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Patent number: 11201721Abstract: A frame synchronization apparatus (10) according to this invention includes a multiplication unit (11) configured to multiply a received signal by an inverse complex number of a predetermined synchronization pattern with respect to a predetermined signal point on a complex space diagram for each of a plurality of symbols of the received signal, an addition average unit (12) configured to perform addition averaging of outputs from the multiplication unit for the plurality of symbols of the received signal, and a synchronization determination unit (13) configured to perform coincidence determination of whether an output from the addition average unit (12) falls within a predetermined coincidence determination range of the predetermined signal point, and determine a synchronization state of the frame synchronization based on a result of the coincidence determination.Type: GrantFiled: February 12, 2021Date of Patent: December 14, 2021Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Mitsuteru Yoshida, Yasuyuki Endoh, Katsuichi Oyama, Masayuki Ikeda, Tsutomu Takeya, Etsushi Yamazaki, Yoshiaki Kisaka, Masahito Tomizawa
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Publication number: 20210344424Abstract: First compensation circuitry includes a first digital filter compensating a phase difference between a phase of a symbol of a received signal and a sampling timing, and first filter coefficient calculation circuitry calculating a filter coefficient of the first digital filter as a first filter coefficient. Second filter coefficient calculation circuitry calculates, as a second filter coefficient, a filter coefficient for adaptive equalization that compensates distortion due to temporally changing polarization dispersion, based on an output of the first digital filter. Coefficient combination circuitry combines the first filter coefficient and the second filter coefficient. Second compensation circuitry includes a second digital filter which uses a filter coefficient combined by the coefficient combination circuitry and performs a compensation of the phase difference between the phase of the symbol of the received signal and the sampling timing, and a process of the adaptive equalization at the same time.Type: ApplicationFiled: October 7, 2019Publication date: November 4, 2021Applicant: NTT Electronics CorporationInventors: Tomohiro TAKAMUKU, Mitsuteru YOSHIDA, Tsutomu TAKEYA, Kazuhito TAKEI, Katsuichi OYAMA, Tomoharu SEMBOKU
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Patent number: 11121778Abstract: A known pattern comparison type phase difference detection unit (12) detects a phase difference between a known pattern extracted from a received signal and a true value of the known pattern as a first phase difference. M indicates the number of modulation phases in a phase modulation method of the received signal. An M-th power type phase difference detection unit (13) removes a modulation component by raising the received signal to M-th power, and detects phase variation from a modulation phase point used for mapping on a transmission side, as a second phase difference. A phase compensation unit (11) compensates phase variation of the received signal based on an addition result of the first phase difference and the second phase difference.Type: GrantFiled: July 22, 2019Date of Patent: September 14, 2021Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Tomohiro Takamuku, Mitsuteru Yoshida, Tsutomu Takeya, Katsuichi Oyama, Hiroyuki Nouchi, Atsushi Suenaga
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Publication number: 20210273777Abstract: A frame synchronization apparatus (10) according to this invention includes a multiplication unit (11) configured to multiply a received signal by an inverse complex number of a predetermined synchronization pattern with respect to a predetermined signal point on a complex space diagram for each of a plurality of symbols of the received signal, an addition average unit (12) configured to perform addition averaging of outputs from the multiplication unit for the plurality of symbols of the received signal, and a synchronization determination unit (13) configured to perform coincidence determination of whether an output from the addition average unit (12) falls within a predetermined coincidence determination range of the predetermined signal point, and determine a synchronization state of the frame synchronization based on a result of the coincidence determination.Type: ApplicationFiled: June 6, 2019Publication date: September 2, 2021Inventors: Mitsuteru YOSHIDA, Yasuyuki ENDOH, Katsuichi OYAMA, Masayuki IKEDA, Tsutomu TAKEYA, Etsushi YAMAZAKI, Yoshiaki KISAKA, Masahito TOMIZAWA
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Publication number: 20210273732Abstract: A known pattern comparison type phase difference detection unit (12) detects a phase difference between a known pattern extracted from a received signal and a true value of the known pattern as a first phase difference. M indicates the number of modulation phases in a phase modulation method of the received signal. An M-th power type phase difference detection unit (13) removes a modulation component by raising the received signal to M-th power, and detects phase variation from a modulation phase point used for mapping on a transmission side, as a second phase difference. A phase compensation unit (11) compensates phase variation of the received signal based on an addition result of the first phase difference and the second phase difference.Type: ApplicationFiled: July 22, 2019Publication date: September 2, 2021Applicant: NTT Electronics CorporationInventors: Tomohiro TAKAMUKU, Mitsuteru YOSHIDA, Tsutomu TAKEYA, Katsuichi OYAMA, Hiroyuki NOUCHI, Atsushi SUENAGA
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Publication number: 20210167939Abstract: A frame synchronization apparatus (10) according to this invention includes a multiplication unit (11) configured to multiply a received signal by an inverse complex number of a predetermined synchronization pattern with respect to a predetermined signal point on a complex space diagram for each of a plurality of symbols of the received signal, an addition average unit (12) configured to perform addition averaging of outputs from the multiplication unit for the plurality of symbols of the received signal, and a synchronization determination unit (13) configured to perform coincidence determination of whether an output from the addition average unit (12) falls within a predetermined coincidence determination range of the predetermined signal point, and determine a synchronization state of the frame synchronization based on a result of the coincidence determination.Type: ApplicationFiled: February 12, 2021Publication date: June 3, 2021Inventors: Mitsuteru YOSHIDA, Yasuyuki ENDOH, Katsuichi OYAMA, Masayuki IKEDA, Tsutomu TAKEYA, Etsushi YAMAZAKI, Yoshiaki KISAKA, Masahito TOMIZAWA
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Publication number: 20210075541Abstract: An error correction device according to this invention includes a first correction unit configured to perform error correction decoding of data by a repetitive operation, and having a full operation state in which the repetitive operation of the error correction decoding is repeated until convergence is obtained and a save operation state in which the number of times of the repetitive operation of the error correction decoding is restricted to a predetermined number of times, an error information estimation unit configured to estimate an input error rate or an output error rate of the first correction unit using a decoding result of the first correction unit, and a control unit configured to control transition between the full operation state and the save operation state of the first correction unit based on at least one piece of information of the input error rate, the output error rate, and an operation time of the first correction unit.Type: ApplicationFiled: December 20, 2018Publication date: March 11, 2021Inventors: Fumiaki NAKAGAWA, Yasuharu ONUMA, Katsuichi OYAMA, Yasuyuki ENDOH, Etsushi YAMAZAKI, Yoshiaki KISAKA, Masahito TOMIZAWA
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Patent number: 10880193Abstract: 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: GrantFiled: December 15, 2017Date of Patent: December 29, 2020Assignees: 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: 10608743Abstract: 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: GrantFiled: May 26, 2017Date of Patent: March 31, 2020Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Tomohiro Takamuku, Etsushi Yamazaki, Katsuichi Oyama, Yasuharu Onuma, Kazuhito Takei, Masanori Nakamura, Mitsuteru Yoshida, Masahito Tomizawa, Yoshiaki Kisaka
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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: 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: 10396895Abstract: In a method in which a compensation coefficient calculating portion (6) calculates a compensation coefficient of a compensation portion (5) which compensates transmission characteristics of a signal, a known signal is extracted from the signal. Next, a pseudo-random number is added to the extracted known signal. Next, the compensation coefficient is calculated by comparing a true value of the known signal with the known signal to which the pseudo-random number is added.Type: GrantFiled: April 26, 2017Date of Patent: August 27, 2019Assignee: NTT ELECTRONICS CORPORATIONInventors: Tomohiro Takamuku, Etsushi Yamazaki, Yuki Yoshida, Katsuichi Oyama, Yasuharu Onuma, Akihiro Yamagishi
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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: 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: 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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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: 20190036613Abstract: In a method in which a compensation coefficient calculating portion (6) calculates a compensation coefficient of a compensation portion (5) which compensates transmission characteristics of a signal, a known signal is extracted from the signal. Next, a pseudo-random number is added to the extracted known signal. Next, the compensation coefficient is calculated by comparing a true value of the known signal with the known signal to which the pseudo-random number is added.Type: ApplicationFiled: April 26, 2017Publication date: January 31, 2019Inventors: Tomohiro TAKAMUKU, Etsushi YAMAZAKI, Yuki YOSHIDA, Katsuichi OYAMA, Yasuharu ONUMA, Akihiro YAMAGISHI