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).
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Patent number: 7466764Abstract: In a delay regulating device, delay regulation is performed using a delay circuit performing delay regulation in a clock unit and a delay filter performing delay regulation in a tap unit smaller than the clock unit. The delay regulation is performed so as to obtain the maximum value of the correlation value and the minimum value of the error signal. First the delay circuit based on the clock unit is used to control the delay amount of the reference signal so as to obtain the maximum value of the correlation value. The delay filter is used to control the delay amount of the feedback signal so as to obtain the maximum value of the correlation value. Phase adjustment of the reference signal and the feedback signal is performed. The delay amount of the feedback signal is regulated so as to minimize the error signal unit using the delay filter.Type: GrantFiled: January 8, 2008Date of Patent: December 16, 2008Assignee: Fujitsu LimitedInventors: Takeshi Ohba, Yasuhito Funyu, Hideharu Shako
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Publication number: 20080299920Abstract: In a transmission device including an RF power amplifier with less number of terminals for monitoring an input/output signal of the RF power amplifier, there are provided with an input signal detector detecting the input signal; an output signal detector detecting the output signal; a first power amplifier switch switching ON or OFF the power amplifier; a monitor terminal; and an RF switch selecting an input signal or output signal of the power amplifier to be transmitted to the monitor terminal, in association with the first power amplifier switch being switched ON or OFF.Type: ApplicationFiled: May 30, 2008Publication date: December 4, 2008Inventors: Hideharu Shako, Takeshi Ohba, Tomoyoshi Nohira
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Patent number: 7447274Abstract: Provided is a distortion compensation apparatus to prevent divergence of distortion compensation coefficients caused by an abnormal distortion compensation coefficient value. The distortion compensation apparatus includes a storage for storing a distortion compensation coefficient in a specified write address, and outputting a distortion compensation coefficient stored in a specified readout address; a predistortion portion for performing distortion compensation processing onto a transmission signal, using the distortion compensation coefficient being output from the storage; and a distortion compensator for calculating a distortion compensation coefficient based on the transmission signal before the distortion compensation processing and the transmission signal after being amplified by an amplifier.Type: GrantFiled: June 30, 2005Date of Patent: November 4, 2008Assignee: Fujitsu, LimitedInventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Patent number: 7443923Abstract: The distortion compensating apparatus which adaptively updates a distortion compensation coefficient for an amplifier based on a difference between input and output signals of the amplifier, comprises: a distortion amount detector which detects the amount of distort of an output signal of the amplifier; a parameter holder which holds a parameter having been set therein; a parameter corrector which corrects the parameter in such a manner that the distortion amount detected by the detector is improved; and a distortion amount corrector which corrects the distortion amount detected by the detector in such a manner that the distortion amount is reduced by an offset amount according to a detection error. This arrangement makes it possible to accurately set the parameter relating to difference detection which is a factor of updating of distortion compensation coefficients of the distortion compensating apparatus.Type: GrantFiled: May 19, 2006Date of Patent: October 28, 2008Assignee: Fujitsu LimitedInventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Patent number: 7433421Abstract: A distortion compensation apparatus is provided to restrain an increased calculation time caused by a large amount of calculation required for obtaining a phase variation amount for compensation from the correlation.Type: GrantFiled: June 8, 2005Date of Patent: October 7, 2008Assignee: Fujitsu LimitedInventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Patent number: 7430249Abstract: The present invention is a carrier state judging device having a multiplexing unit multiplexing carrier signals to be inputted in parallel, output control units inputted to the multiplexing unit and performing ON/OFF control of outputs of the carrier signals inputted to the output control units themselves according to predetermined ON/OFF setting values, frequency shift units and giving predetermined frequency shift quantities to the carrier signals inputted to the frequency shift units themselves, a detection unit detecting as to whether or not there is the carrier signal flowing through on each carrier signal transmission path, and a determining unit determining a state of the carrier signals multiplexed by the multiplexing unit on the basis of the ON/OFF setting value with respect to each of the output control units, the frequency shift quantity with respect to each of the frequency shift units and a result of the detection by the detection unit.Type: GrantFiled: October 13, 2006Date of Patent: September 30, 2008Assignee: Fujitsu LimitedInventors: Takeshi Ohba, Yasuhito Funyu, Hideharu Shako
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Patent number: 7430250Abstract: The number of times of referring to of a storing unit in a distortion compensating apparatus is averaged and temporary degradation of the distortion property is avoided. The distortion compensating apparatus include a pre-distorting unit that applies a distortion compensating process to a transmission signal using a distortion compensation coefficient, a distortion compensation calculating unit that calculates a distortion compensation coefficient based on the transmission signal before the distortion compensation and a feedback fed back from an output of a distortion device, an address generating circuit that produces an address corresponding to the transmission signal, and a storing unit that updates the calculated distortion compensation coefficient to the produced address and that stores the produced address.Type: GrantFiled: August 22, 2007Date of Patent: September 30, 2008Assignee: Fujitsu LimitedInventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Patent number: 7418057Abstract: To shorten the time required for writing of the distortion compensation coefficient and to reduce amount of data of the distortion compensation coefficient stored as the initial value of the distortion compensation apparatus. The distortion compensation apparatus for amplifying the transmitting signal after implementing the distortion compensation process comprises a coefficient memory for storing corresponding to each address the coefficient used for the distortion compensation process, an initial value memory for storing the initial value of the coefficient, and a controller for write control corresponding to n (n: natural number equal to 2 or larger) addresses of the coefficient read from the initial value memory corresponding to one address.Type: GrantFiled: April 25, 2005Date of Patent: August 26, 2008Assignee: Fujitsu LimitedInventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Patent number: 7418058Abstract: The present apparatus includes: distortion amount detector which detects the amount of distortion of an output signal of the amplifier; parameter holder; parameter corrector which corrects a parameter held in the parameter holder in such a manner that the distortion amount detected by the distortion amount detector is improved; controller which controls frequency components to be subjected to distortion amount detection that is performed by the distortion amount detector, based on the distortion amounts of a plurality of different frequency components of the output signal of the amplifier and on specification values relating to the distortion amounts. This arrangement makes it possible to set (control) appropriate distortion data measurement point (frequency component to be detected) according to multiple specification values (for example, ACLR specification values) relating to the distortion amount.Type: GrantFiled: August 15, 2006Date of Patent: August 26, 2008Assignee: Fujitsu LimitedInventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Patent number: 7405680Abstract: A distortion compensator updating and selecting a distortion compensation coefficient applied to a digital transmission signal so as to reduce the difference between the digital transmission signal and a digital feedback signal is disclosed. The distortion compensator includes a control part that controls the level of an input signal to an analog-to-digital conversion part outputting the digital feedback signal in accordance with the magnitude of the amplitude of the digital transmission signal.Type: GrantFiled: May 20, 2004Date of Patent: July 29, 2008Assignee: Fujitsu LimitedInventors: Yasuhito Funyu, Hiroaki Abe, Takeshi Ohba, Tomohiro Nakamura
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Publication number: 20080130798Abstract: In a delay regulating device, delay regulation is performed using a delay circuit performing delay regulation in a clock unit and a delay filter performing delay regulation in a tap unit smaller than the clock unit. The delay regulation is performed so as to obtain the maximum value of the correlation value and the minimum value of the error signal. First the delay circuit based on the clock unit is used to control the delay amount of the reference signal so as to obtain the maximum value of the correlation value. The delay filter is used to control the delay amount of the feedback signal so as to obtain the maximum value of the correlation value. Phase adjustment of the reference signal and the feedback signal is performed. The delay amount of the feedback signal is regulated so as to minimize the error signal unit using the delay filter.Type: ApplicationFiled: January 8, 2008Publication date: June 5, 2008Applicant: FUJITSU LIMITEDInventors: Takeshi Ohba, Yasuhito Funyu, Hideharu Shako
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Publication number: 20080111723Abstract: A reference signal and a feedback signal are written to memory and the state of a power value of a reference signal is used for judging whether the current signal is in a normal state, burst state, non-modulation state or no-wave transmission state. If the state is judged to be the burst state or no-wave transmission state, a DC offset correction is performed by selecting a feedback signal type DC offset correction method in which a DC offset is corrected by using only a feedback signal. If the state is judged to be the normal state or non-modulation state, a DC offset correction is performed by selecting a reference signal type DC offset correction method in which a DC offset is corrected by using a differential signal between the reference signal and feedback signal.Type: ApplicationFiled: January 18, 2008Publication date: May 15, 2008Applicant: FUJITSU LIMITEDInventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Patent number: 7352308Abstract: It is an object of the present invention to provide a DC offset correction means capable of correctly performing DC offset correction even when transmitting a non-modulation signal in radio communication equipment for performing orthogonal modulation by a direct RF modulation method. The DC offset correction device comprises a fixed value setting unit for setting a value for outputting a non-modulation signal with a specific phase from a modulator, a non-modulation signal switch unit for switching between a main signal and the value set by the fixed value setting unit and a DC offset correction control unit for sequentially changing the specific phase of the non-modulation signal outputted from the modulator by sequentially changing the value set by the fixed value setting unit and operating a DC offset correction value to be added to an input signal by a DC offset correction unit, based on feedback signal data generated from the non-modulation signal whose phase is sequentially changed.Type: GrantFiled: April 20, 2006Date of Patent: April 1, 2008Assignee: Fujitsu LimitedInventors: Takeshi Ohba, Yasuhito Funyu, Hideharu Shako
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Patent number: 7327191Abstract: The distortion compensating apparatus, which adaptively updates a distortion compensation coefficient for an amplifier based on a difference between input and output signals of the amplifier, comprises: a distortion amount detector which detects the amount of distortion of an output signal of the amplifier; a parameter holder which holds a parameter having been set therein; a parameter corrector which corrects the parameter in such a manner that the distortion amount detected by the detector is improved; a power monitor which monitors output power of the amplifier or a factor of variation in the power; and a controller which halts, if a monitoring result by the power monitor is smaller than a specified threshold value, the correction of the parameter. This arrangement makes it possible to accurately set the parameter relating to difference detection which is a factor of updating of distortion compensation coefficients of the distortion compensating apparatus.Type: GrantFiled: May 19, 2006Date of Patent: February 5, 2008Assignee: Fujitsu LimitedInventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Publication number: 20080003958Abstract: The present invention is a carrier state judging device having a multiplexing unit multiplexing carrier signals to be inputted in parallel, output control units inputted to the multiplexing unit and performing ON/OFF control of outputs of the carrier signals inputted to the output control units themselves according to predetermined ON/OFF setting values, frequency shift units and giving predetermined frequency shift quantities to the carrier signals inputted to the frequency shift units themselves, a detection unit detecting as to whether or not there is the carrier signal flowing through on each carrier signal transmission path, and a determining unit determining a state of the carrier signals multiplexed by the multiplexing unit on the basis of the ON/OFF setting value with respect to each of the output control units, the frequency shift quantity with respect to each of the frequency shift units and a result of the detection by the detection unit.Type: ApplicationFiled: October 13, 2006Publication date: January 3, 2008Inventors: Takeshi Ohba, Yasuhito Funyu, Hideharu Shako
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Publication number: 20070296495Abstract: The number of times of referring to of a storing unit in a distortion compensating apparatus is averaged and temporary degradation of the distortion property is avoided. The distortion compensating apparatus include a pre-distorting unit that applies a distortion compensating process to a transmission signal using a distortion compensation coefficient, a distortion compensation calculating unit that calculates a distortion compensation coefficient based on the transmission signal before the distortion compensation and a feedback fed back from an output of a distortion device, an address generating circuit that produces an address corresponding to the transmission signal, and a storing unit that updates the calculated distortion compensation coefficient to the produced address and that stores the produced address.Type: ApplicationFiled: August 22, 2007Publication date: December 27, 2007Applicant: FUJITSU LIMITEDInventors: Hideharu SHAKO, Yasuhito FUNYU, Takeshi OHBA
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Publication number: 20070274471Abstract: The apparatus includes: distortion amount detector which detects the amount of distortion of an output signal of an amplifier; parameter holder which holds a parameter having been set therein, the parameter holder being capable of varying the difference according to the parameter set therein; parameter corrector which corrects the parameter held in the parameter holder in such a manner that the distortion amount detected by the distortion amount detector is improved; noise component detector which detects a noise component that can be caused in the output signal resulting from a quadrature modulation; and noise component remover which performs processing for removing the noise component detected by the noise component detector. This arrangement makes it possible to suppress image frequency component generation in an output signal of the amplifier accompanying quadrature modulation and to optimize parameters in distortion compensation.Type: ApplicationFiled: September 28, 2006Publication date: November 29, 2007Inventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Publication number: 20070253566Abstract: The present apparatus includes: distortion amount detector which detects the amount of distortion of an output signal of the amplifier; parameter holder; parameter corrector which corrects a parameter held in the parameter holder in such a manner that the distortion amount detected by the distortion amount detector is improved; controller which controls frequency components to be subjected to distortion amount detection that is performed by the distortion amount detector, based on the distortion amounts of a plurality of different frequency components of the output signal of the amplifier and on specification values relating to the distortion amounts. This arrangement makes it possible to set (control) appropriate distortion data measurement point (frequency component to be detected) according to multiple specification values (for example, ACLR specification values) relating to the distortion amount.Type: ApplicationFiled: August 15, 2006Publication date: November 1, 2007Inventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba
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Patent number: 7274914Abstract: A power correction value generating unit determines a power correction value for minimizing an error, from a reference output power value of a carrier multiplexed signal, generating due to peak power suppression under a carrier setting based on the carrier setting relating to either one or both of the number of carrier signals and frequency arrangement, and peak suppression setting. An output power error correcting unit corrects a signal gain before or after the carrier signals are multiplexed, using the power correction value obtained by the power correction value generating unit. In an apparatus performing peak suppression according to an input limitation power of the power amplifier, it is possible to always obtain a desirable transmission (output) power even when the number of carriers or carrier frequency arrangement varies.Type: GrantFiled: December 21, 2004Date of Patent: September 25, 2007Assignee: Fujitsu LimitedInventors: Takeshi Ohba, Yasuhito Funyu, Hiroaki Abe, Tomohiro Nakamura
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Publication number: 20070200625Abstract: The distortion compensating apparatus which adaptively updates a distortion compensation coefficient for an amplifier based on a difference between input and output signals of the amplifier, comprises: a distortion amount detector which detects the amount of distort of an output signal of the amplifier; a parameter holder which holds a parameter having been set therein; a parameter corrector which corrects the parameter in such a manner that the distortion amount detected by the detector is improved; and a distortion amount corrector which corrects the distortion amount detected by the detector in such a manner that the distortion amount is reduced by an offset amount according to an detection error. This arrangement makes it possible to accurately set the parameter relating to difference detection which is a factor of updating of distortion compensation coefficients of the distortion compensating apparatus.Type: ApplicationFiled: May 19, 2006Publication date: August 30, 2007Inventors: Hideharu Shako, Yasuhito Funyu, Takeshi Ohba