Patents by Inventor Takeshi Ohba

Takeshi Ohba 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).

  • Publication number: 20240126479
    Abstract: According to one embodiment, a controller includes a first interface, a second interface, a virtual register table, a memory management unit and a calculation processing unit. The first interface receives an I/O command from a host. The second interface transmits and receives first host data to and from a storage. The virtual register table has a virtual address specified by a page number assigned to a page in which data to be used to process a calculation instruction is stored and a page offset, and a data size of the data. The memory management unit stores, into a memory, the copy of the first host data, and updates the virtual register table. The calculation processing unit processes the calculation instruction by referring to the virtual register table.
    Type: Application
    Filed: October 9, 2023
    Publication date: April 18, 2024
    Inventors: Yoshihiro OHBA, Tomoya SANUKI, Takeshi ISHIHARA
  • Publication number: 20170302389
    Abstract: A wireless communication device includes: a transmitting circuit that is connected to an antenna and includes a power amplifier that amplifies an input signal; a receiving circuit that is connected to the antenna and includes a switch that switches as to whether or not a signal is received; and a processor that executes a process including: acquiring timing information that indicates timing of a guard period when no signal is transmitted or received by the antenna; turning on the power amplifier and turning on the switch in the guard period based on the acquired timing information to input a noise signal of the transmitting circuit that is amplified by the power amplifier to the receiving circuit; measuring electrical power of a signal that is output from the receiving circuit in the guard period; and determining abnormality of the receiving circuit based on the measured electrical power.
    Type: Application
    Filed: March 24, 2017
    Publication date: October 19, 2017
    Applicant: FUJITSU LIMITED
    Inventors: HIRO YOSHIDA, Junya MORITA, Takuro Nishikawa, Takeshi OHBA, Akifumi Adachi, Shinichiro Kobayashi, Satoshi Matsubara, Yasushi Seino, Kouichi Hayasaka, Shunsuke Satou
  • Patent number: 8897391
    Abstract: A distortion compensator compensates for distortion of a signal caused by an amplifier. A storage section stores a plurality of compensation coefficients used for distortion compensation. A selection section selects a compensation coefficient corresponding to an index value indicative of a power level of the signal from among the plurality of compensation coefficients. The selection section determines whether or not the power level is higher than a threshold, and uses, based on a determination result, a first index value calculated without using a logarithmic operation or a second index value calculated by using a logarithmic operation.
    Type: Grant
    Filed: September 12, 2012
    Date of Patent: November 25, 2014
    Assignee: Fujitsu Limited
    Inventors: Daisuke Masunaga, Satoshi Matsubara, Takeshi Ohba, Hideharu Shako
  • Patent number: 8798197
    Abstract: A distortion compensation amplifier device for compensating for distortion of a transmission signal generated by amplifying the transmission signal and for outputting the compensated transmission signal. The distortion compensation amplifier includes a storage unit that stores therein distortion compensation coefficients; a processor that performs distortion compensation processing on the transmission signal by using one of the distortion compensation coefficients; and an amplifier that amplifies the transmission signal that has been subjected to the distortion compensation processing; wherein the processor calculates an average value of the distortion compensation coefficients stored in the storage unit, and calculates the distortion compensation coefficient on the basis of the transmission signal, and the average value.
    Type: Grant
    Filed: August 5, 2011
    Date of Patent: August 5, 2014
    Assignee: Fujitsu Limited
    Inventors: Satoshi Matsubara, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama
  • Patent number: 8565697
    Abstract: A distortion compensation apparatus having a circuit configured to perform power amplification of a transmission signal; and a circuit configured to feedback the transmission signal output from the circuit configured to perform power amplification and obtain a demodulated signal of the transmission signal, while calculating and holding a distortion compensation coefficient with which an error between the demodulated signal and the transmission signal before the power amplification becomes minimum, to perform distortion compensation of the transmission signal based on the distortion compensation coefficient and provide the compensated transmission signal to the circuit configured to perform the power amplification, the distortion compensation apparatus includes: a gain adjustment unit to adjust a gain of the transmission signal; and a gain control unit to adaptively adjust a gain of the gain adjustment unit based on the held distortion compensation coefficient.
    Type: Grant
    Filed: January 21, 2010
    Date of Patent: October 22, 2013
    Assignee: Fujitsu Limited
    Inventors: Hideharu Shako, Takeshi Ohba
  • Patent number: 8472578
    Abstract: A radio apparatus includes: first and second reception units to receive first and second signals from first and second radio apparatus controllers, respectively; first and second synchronous clock generation units to generate first and second recovery clocks from clock components included in the first and second signals received by the reception units, respectively; a clock synchronization detection unit to detect whether or not the second recovery clock is synchronous with the first recovery clock; a code selection unit to select a code indicating the synchronous state according to a detection result of the synchronization detection unit; a signal processing unit of generate a third signal to which the code selected by the code selection unit is added and which is synchronous with the first recovery clock; and a transmission unit to transmit the third signal generated by the signal processing unit to the second radio apparatus controller.
    Type: Grant
    Filed: February 1, 2012
    Date of Patent: June 25, 2013
    Assignee: Fujitsu Limited
    Inventors: Hideharu Shako, Takeshi Ohba, Satoshi Matsubara
  • Patent number: 8461925
    Abstract: A distortion compensating apparatus that compensates signal distortion caused by an amplifier includes a distortion compensating process unit that using a distortion compensation coefficient, compensates distortion of an input signal; a memory unit that stores the distortion compensation coefficient; and an address generating unit that generates a first address that is based on electrical power of the input signal and for acquiring the distortion compensation coefficient from the memory unit and that generates a second address that is based on a phase of the input signal and for acquiring the distortion compensation coefficient from the memory unit. The distortion compensating process unit acquires the distortion compensation coefficient from the memory unit based on the first and the second addresses to compensate the distortion.
    Type: Grant
    Filed: January 13, 2011
    Date of Patent: June 11, 2013
    Assignee: Fujitsu Limited
    Inventors: Satoshi Matsubara, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama
  • Patent number: 8442157
    Abstract: A wireless apparatus includes: an A/D converter which samples an in-phase signal component and a quadrature signal component from a quadrature-modulated signal of analog form alternately; a digital quadrature demodulation unit which applies digital quadrature demodulation to an output signal of the A/D converter and outputs an in-phase signal and a quadrature signal; and an error detection unit which, based on the in-phase and quadrature signals output from the digital quadrature demodulation unit, detects a time difference error between the sample timing of the in-phase signal component and the sample timing of the quadrature signal component.
    Type: Grant
    Filed: June 4, 2010
    Date of Patent: May 14, 2013
    Assignee: Fujitsu Limited
    Inventors: Hiroyoshi Ishikawa, Kazuo Nagatani, Hajime Hamada, Nobukazu Fudaba, Yuichi Utsunomiya, Takeshi Ohba, Hideharu Shako, Yasuhito Funyu
  • Patent number: 8437425
    Abstract: A distortion compensation device includes a storage unit storing a plurality of distortion compensation coefficients associated with power values of transmission signals, a distortion compensation processing unit acquiring a distortion compensation coefficient corresponding to a power value of a received transmission signal from among the plurality of distortion compensation coefficients and subjecting the received transmission signal to a distortion compensation process on the basis of the acquired distortion compensation coefficient, a phase calculating unit calculating a phase correction value on the basis of the distortion compensation coefficients, a phase correcting unit generating a reference signal by correcting a phase of the received transmission signal on the basis of the phase correction value, and a correction processing unit performing a correction process for the transmission signal subjected to the distortion compensation process on the basis of the reference signal and a feedback signal from
    Type: Grant
    Filed: November 4, 2011
    Date of Patent: May 7, 2013
    Assignee: Fujitsu Limited
    Inventors: Satoshi Matsubara, Takeshi Ohba, Hideharu Shako
  • Publication number: 20130083866
    Abstract: A distortion compensator compensates for distortion of a signal caused by an amplifier. A storage section stores a plurality of compensation coefficients used for distortion compensation. A selection section selects a compensation coefficient corresponding to an index value indicative of a power level of the signal from among the plurality of compensation coefficients. The selection section determines whether or not the power level is higher than a threshold, and uses, based on a determination result, a first index value calculated without using a logarithmic operation or a second index value calculated by using a logarithmic operation.
    Type: Application
    Filed: September 12, 2012
    Publication date: April 4, 2013
    Applicant: FUJITSU LIMITED
    Inventors: Daisuke MASUNAGA, Satoshi MATSUBARA, Takeshi OHBA, Hideharu SHAKO
  • Patent number: 8384477
    Abstract: A distortion compensating apparatus that compensates signal distortion caused by an amplifier includes a distortion compensating process unit that using a distortion compensation coefficient, compensates distortion of an input signal; a memory unit storing therein the distortion compensation coefficient; and an address generating unit that generates a first address that is based on electrical power of the input signal and is for acquiring the distortion compensation coefficient from the memory unit, and a second address that is based on any one among the electrical power, phase of the input signal and amplitude of the input signal, is for acquiring the distortion compensation coefficient from the memory unit, and is normalized in a normalizing range determined according to the electrical power of the input signal. The distortion compensating process unit acquires the distortion compensation coefficient from the memory unit, based on the first and the second addresses to compensate the distortion.
    Type: Grant
    Filed: January 6, 2011
    Date of Patent: February 26, 2013
    Assignee: Fujitsu Limited
    Inventors: Satoshi Matsubara, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama
  • Patent number: 8351878
    Abstract: When a distortion correction coefficient, which is calculated according to a signal input to a power amplifier and a signal output from the power amplifier, is larger than a first threshold, a distortion correction coefficient corresponding to the input signal is updated to the first threshold. When the calculated distortion correction coefficient is equal to or smaller than the first threshold, the distortion correction coefficient corresponding to the input signal is updated to the calculated distortion correction coefficient.
    Type: Grant
    Filed: February 14, 2011
    Date of Patent: January 8, 2013
    Assignee: Fujitsu Limited
    Inventors: Satoshi Matsubara, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama
  • Patent number: 8311493
    Abstract: An error between the power of an input signal, which is input to a power amplifier, and the power of an output signal, which is output from the power amplifier, is calculated. The calculated error is normalized according to the power of the input signal or the power of the output signal. A distortion correction coefficient, which is stored in a predetermined storage unit in association with the power of the input signal, is updated using the normalized error.
    Type: Grant
    Filed: February 17, 2011
    Date of Patent: November 13, 2012
    Assignee: Fujitsu Limited
    Inventors: Satoshi Matsubara, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama
  • Publication number: 20120250738
    Abstract: A radio apparatus includes: first and second reception units to receive first and second signals from first and second radio apparatus controllers, respectively; first and second synchronous clock generation units to generate first and second recovery clocks from clock components included in the first and second signals received by the reception units, respectively; a clock synchronization detection unit to detect whether or not the second recovery clock is synchronous with the first recovery clock; a code selection unit to select a code indicating the synchronous state according to a detection result of the synchronization detection unit; a signal processing unit of generate a third signal to which the code selected by the code selection unit is added and which is synchronous with the first recovery clock; and a transmission unit to transmit the third signal generated by the signal processing unit to the second radio apparatus controller.
    Type: Application
    Filed: February 1, 2012
    Publication date: October 4, 2012
    Applicant: FUJITSU LIMITED
    Inventors: Hideharu SHAKO, Takeshi Ohba, Satoshi Matsubara
  • Publication number: 20120147991
    Abstract: A distortion compensation device includes a storage unit storing a plurality of distortion compensation coefficients associated with power values of transmission signals, a distortion compensation processing unit acquiring a distortion compensation coefficient corresponding to a power value of a received transmission signal from among the plurality of distortion compensation coefficients and subjecting the received transmission signal to a distortion compensation process on the basis of the acquired distortion compensation coefficient, a phase calculating unit calculating a phase correction value on the basis of the distortion compensation coefficients, a phase correcting unit generating a reference signal by correcting a phase of the received transmission signal on the basis of the phase correction value, and a correction processing unit performing a correction process for the transmission signal subjected to the distortion compensation process on the basis of the reference signal and a feedback signal from
    Type: Application
    Filed: November 4, 2011
    Publication date: June 14, 2012
    Applicant: FUJITSU LIMITED
    Inventors: Satoshi MATSUBARA, Takeshi OHBA, Hideharu SHAKO
  • Publication number: 20120039415
    Abstract: A distortion compensation amplifier device for compensating for distortion of a transmission signal generated by amplifying the transmission signal and for outputting the compensated transmission signal. The distortion compensation amplifier includes a storage unit that stores therein distortion compensation coefficients; a processor that performs distortion compensation processing on the transmission signal by using one of the distortion compensation coefficients; and an amplifier that amplifies the transmission signal that has been subjected to the distortion compensation processing; wherein the processor calculates an average value of the distortion compensation coefficients stored in the storage unit, and calculates the distortion compensation coefficient on the basis of the transmission signal, and the average value.
    Type: Application
    Filed: August 5, 2011
    Publication date: February 16, 2012
    Applicant: FUJITSU LIMITED
    Inventors: Satoshi MATSUBARA, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama
  • Patent number: 8081029
    Abstract: There is provided a distortion compensation apparatus for compensating distortion of an output of a power amplifier included in a radio transmitter. The distortion compensation apparatus includes a difference value calculator to calculate a difference value between a reference signal and a feedback signal, where the reference signal is branched from an input signal to the power amplifier and the feedback signal is branched from an output from the power amplifier; an integrator to accumulate the difference value; and a failure determiner to determine based on the accumulated difference value whether or not a failure has occurred or not.
    Type: Grant
    Filed: April 20, 2010
    Date of Patent: December 20, 2011
    Assignee: Fujitsu Limited
    Inventors: Takeshi Ohba, Hideharu Shako
  • Publication number: 20110227643
    Abstract: A distortion compensating apparatus that compensates signal distortion caused by an amplifier includes a distortion compensating process unit that using a distortion compensation coefficient, compensates distortion of an input signal; a memory unit storing therein the distortion compensation coefficient; and an address generating unit that generates a first address that is based on electrical power of the input signal and is for acquiring the distortion compensation coefficient from the memory unit, and a second address that is based on any one among the electrical power, phase of the input signal and amplitude of the input signal, is for acquiring the distortion compensation coefficient from the memory unit, and is normalized in a normalizing range determined according to the electrical power of the input signal. The distortion compensating process unit acquires the distortion compensation coefficient from the memory unit, based on the first and the second addresses to compensate the distortion.
    Type: Application
    Filed: January 6, 2011
    Publication date: September 22, 2011
    Applicant: FUJITSU LIMITED
    Inventors: Satoshi Matsubara, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama
  • Publication number: 20110227644
    Abstract: A distortion compensating apparatus that compensates signal distortion caused by an amplifier includes a distortion compensating process unit that using a distortion compensation coefficient, compensates distortion of an input signal; a memory unit that stores the distortion compensation coefficient; and an address generating unit that generates a first address that is based on electrical power of the input signal and for acquiring the distortion compensation coefficient from the memory unit and that generates a second address that is based on a phase of the input signal and for acquiring the distortion compensation coefficient from the memory unit. The distortion compensating process unit acquires the distortion compensation coefficient from the memory unit based on the first and the second addresses to compensate the distortion.
    Type: Application
    Filed: January 13, 2011
    Publication date: September 22, 2011
    Applicant: FUJITSU LIMITED
    Inventors: Satoshi Matsubara, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama
  • Publication number: 20110221525
    Abstract: An error between the power of an input signal, which is input to a power amplifier, and the power of an output signal, which is output from the power amplifier, is calculated. The calculated error is normalized according to the power of the input signal or the power of the output signal. A distortion correction coefficient, which is stored in a predetermined storage unit in association with the power of the input signal, is updated using the normalized error.
    Type: Application
    Filed: February 17, 2011
    Publication date: September 15, 2011
    Applicant: FUJITSU LIMITED
    Inventors: Satoshi Matsubara, Shuya Hirata, Takeshi Ohba, Hideharu Shako, Jun Sugiyama