Patents by Inventor Yasuyuki Oishi
Yasuyuki Oishi 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: 20060131414Abstract: A MIMO wireless communication system and wireless communication apparatuses are disclosed that increase the practically usable communication channel capacity in the Shannon channel capacity that determines the ratio of maximum signal transmission speed to frequency. Each wireless communication apparatus includes antenna units that transmit and receive radio frequency signals, and a weight controlling unit that provides weights with respect to the antenna units. The antenna units are formed by adaptive array antenna units that can change the directivity by varying weights with respect to antenna elements.Type: ApplicationFiled: February 15, 2006Publication date: June 22, 2006Inventors: Yuuta Nakaya, Takeshi Toda, Yasuyuki Oishi, Kaoru Yokoo
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Patent number: 7035672Abstract: A MIMO wireless communication system and wireless communication apparatuses are disclosed that increase the practically usable communication channel capacity in the Shannon channel capacity that determines the ratio of maximum signal transmission speed to frequency. Each wireless communication apparatus includes antenna units that transmit and receive radio frequency signals, and a weight controlling unit that provides weights with respect to the antenna units. The antenna units are formed by adaptive array antenna units that can change the directivity by varying weights with respect to antenna elements.Type: GrantFiled: March 16, 2004Date of Patent: April 25, 2006Assignee: Fujitsu LimitedInventors: Yuuta Nakaya, Takeshi Toda, Yasuyuki Oishi, Kaoru Yokoo
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Patent number: 7030807Abstract: The invention relates to a radar device for measuring a relative distance to a target. It is an object of the invention to precisely determine the relative distance to the target in a wide range. The radar device according to the invention generates a second pulse by demodulating a signal arriving from a target as a response to a wave signal modulated with a first pulse. The radar device evaluates, as the relative distance to the target, such two different instances that an absolute value of a deviation of a ratio of two instantaneous values of the second pulse from a reference value as a ratio of two instantaneous values of the first pulse is to be minimum. The respective two instantaneous values are with a predetermined interval therebetween on a time axis.Type: GrantFiled: March 10, 2005Date of Patent: April 18, 2006Assignee: Fujitsu LimitedInventors: Kaoru Yokoo, Yasuyuki Oishi
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Patent number: 7026991Abstract: Disclosed is a method of controlling direction of radio-wave emission of a base-station transmitter which emits radio waves upon providing the radio waves with directivity in the direction of a receiver. Two antennas of a base station that are disposed at different positions transmit first and second signals that have been spread by mutually orthogonal spreading codes. A mobile station has a phase detector for receiving the first and second signals transmitted from respective ones of the antennas and obtaining a phase difference between these signals, and a direction estimator for calculating the direction of the mobile station, as seen from the base station, based upon the phase difference and for feeding back a signal representing the calculated direction from the mobile station to the base station. The transmitter of the base station transmits data toward the receiver in the calculated direction using a directional antenna.Type: GrantFiled: June 3, 2004Date of Patent: April 11, 2006Assignee: Fujitsu LimitedInventors: Hajime Hamada, Michiharu Nakamura, Yasuyuki Oishi
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Patent number: 7020447Abstract: Distortion compensation coefficients for correcting distortion of a transmission power amplifier are stored in a memory beforehand, a distortion compensation coefficient conforming to powers or amplitudes of a present transmit signal and a past transmit signal is read out of the memory, and distortion compensation processing is applied to the transmit signal using this distortion compensation coefficient. The transmit signal thus subjected to distortion compensation processing is then amplified by the transmission power amplifier and the amplified signal is transmitted, and the distortion compensation coefficient is updated based upon the transmit signal before distortion compensation and an output signal from the transmission power amplifier.Type: GrantFiled: December 6, 2001Date of Patent: March 28, 2006Assignee: Fujitsu LimitedInventors: Kazuo Nagatani, Yasuyuki Oishi, Tokuro Kubo, Takayoshi Ode, Takeshi Takano, Toru Maniwa
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Patent number: 7012969Abstract: Disclosed is a distortion compensating apparatus for correcting the size of a distortion compensation coefficient in such a manner that a transmit signal that has undergone distortion compensation will not exceed the dynamic range of a DA converter. Specifically, before a distortion compensation coefficient hn+1(p) that has been calculated by a calculation unit is stored in a coefficient memory, an assumption is made that distortion compensation will be performed using the distortion compensation coefficient hn+1(p). Then it is determined beforehand whether a signal x(t)*hn+1(p) that will be obtained by this distortion compensation will exceed the limit of a DA converter. If the limit will be exceeded, the size of the distortion compensation coefficient is reduced by a correction unit, the corrected distortion compensation coefficient is stored in the memory and the transmit signal is corrected using the stored distortion compensation coefficient.Type: GrantFiled: December 14, 2000Date of Patent: March 14, 2006Assignee: Fujitsu LimitedInventors: Takayoshi Ode, Yasuyuki Oishi, Tokuro Kubo, Kazuo Nagatani, Hajime Hamada, Hiroyoshi Ishikawa
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Publication number: 20060038659Abstract: A system establishes synchronicity of transmission and receiving for each reader/writer of an RF tag independently without obtaining synchronization of the reader/writers by means of an unspecified number of control terminals is desired as a reader/writer system. A reader/writer comprises a transmitter operable to transmit an interrogation signal to an RF tag, and a receiver operable to receive a response signal from an RF tag, wherein the transmitter is operable to transmit an interrogation signal based on a synchronization signal received from another reader/writer.Type: ApplicationFiled: May 17, 2005Publication date: February 23, 2006Inventors: Takeshi Takano, Tomohiko Taniguchi, Yasuyuki Oishi, Yoshinori Tanaka, Teruhisa Ninomiya, Nobuhisa Aoki, Yuichi Nakanishi
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Patent number: 6989721Abstract: An adaptive controller adaptively controls a plurality of variable high frequency devices. A calculation part calculates a scalar function value by using a signal varied in accordance with impedances of the variable high frequency devices, a reference signal, and a predetermined scalar function. An impedance variation part creates a signal that sequentially varies the impedances of the variable high frequency devices. A determination part determines, when the impedance of one of the variable high frequency devices is varied, whether a direction in which the scalar function value is varied is in a predetermined sloped direction. The impedance variation part includes a first variation part that, when a decision result in the determination part is in the predetermined direction, creates a signal that further varies the impedance of the one of the variable high frequency devices in the predetermined sloped direction.Type: GrantFiled: March 18, 2004Date of Patent: January 24, 2006Assignee: Fujitsu LimitedInventors: Takeshi Toda, Yuuta Nakaya, Yasuyuki Oishi, Kaoru Yokoo, Shinsuke Hara, Yuji Irie
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Publication number: 20060012527Abstract: An antenna comprises a dielectric member, an antenna pattern formed on one surface of the dielectric member, and a ground pattern formed on the other surface of the dielectric member. A part or the whole of the antenna is implanted in a dielectric layer on the side from which a laser beam does not come in of an optical recording medium symmetrically having a metal layer reflecting the laser beam and the dielectric layer, thereby to provide a radio tag antenna structure for an optical recording medium which is simple, is small-sized, and can secure necessary reading performance.Type: ApplicationFiled: November 30, 2004Publication date: January 19, 2006Inventors: Manabu Kai, Yasuyuki Oishi, Toru Maniwa, Hiroyuki Hayashi, Andrey Andrenko
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Patent number: 6980604Abstract: The present invention provides a transmission device for predistorting a digital signal in order to compensate distortion, then amplifying and transmitting it. A digital input signal is converted to a first analog signal by a first D/A converter. Separately, the digital input signal is also subjected to predistortion. A compensating signal is then generated from the digital input signal and the predistorted signal. The compensating signal generated thereby is converted into a second analog signal by a second D/A converter. The first analog signal and second analog signal are then added, this addition operation giving a compensated analog transmission signal. This analog transmission signal is supplied to the amplifier for amplification, and then transmitted via an antenna.Type: GrantFiled: October 9, 2001Date of Patent: December 27, 2005Assignee: Fujitsu LimitedInventors: Tokuro Kubo, Takayoshi Ode, Kazuo Nagatani, Hajime Hamada, Hiroyoshi Ishikawa, Yasuyuki Oishi, Nobukazu Fudaba
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Publication number: 20050226346Abstract: Disclosed is a distortion compensating apparatus for correcting the size of a distortion compensation coefficient in such a manner that a transmit signal that has undergone distortion compensation will not exceed the dynamic range of a DA converter. Specifically, before a distortion compensation coefficient hn+1(p) that has been calculated by a calculation unit is stored in a coefficient memory, an assumption is made that distortion compensation will be performed using the distortion compensation coefficient hn+1(p). Then it is determined beforehand whether a signal x(t)*hn+1(p) that will be obtained by this distortion compensation will exceed the limit of a DA converter. If the limit will be exceeded, the size of the distortion compensation coefficient is reduced by a correction unit, the corrected distortion compensation coefficient is stored in the memory and the transmit signal is corrected using the stored distortion compensation coefficient.Type: ApplicationFiled: June 10, 2005Publication date: October 13, 2005Inventors: Takayoshi Ode, Yasuyuki Oishi, Tokuro Kubo, Kazuo Nagatani, Hajime Hamada, Hiroyoshi Ishikawa
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Publication number: 20050184922Abstract: A control device for an antenna matching circuit is configured to output an adjusting signal for changing impedance of an element in the antenna matching circuit based on change over time in signal power ratio of a reflected signal from the antenna matching circuit to an incident signal to the antenna matching circuit.Type: ApplicationFiled: June 22, 2004Publication date: August 25, 2005Applicant: FUJITSU LIMITEDInventors: Ichirou Ida, Jun-ichi Takada, Takeshi Toda, Yasuyuki Oishi
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Publication number: 20050174281Abstract: The invention relates to a radar device for measuring a relative distance to a target. It is an object of the invention to precisely determine the relative distance to the target in a wide range. The radar device according to the invention generates a second pulse by demodulating a signal arriving from a target as a response to a wave signal modulated with a first pulse. The radar device evaluates, as the relative distance to the target, such two different instances that an absolute value of a deviation of a ratio of two instantaneous values of the second pulse from a reference value as a ratio of two instantaneous values of the first pulse is to be minimum. The respective two instantaneous values are with a predetermined interval therebetween on a time axis.Type: ApplicationFiled: March 10, 2005Publication date: August 11, 2005Inventors: Kaoru Yokoo, Yasuyuki Oishi
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Publication number: 20050146387Abstract: A control unit and a control method are disclosed. First and second changing units change impedances of two or more first and second components within predetermined first and second ranges, respectively, the first and the second components affecting an output signal. An evaluation function value calculating unit calculates an evaluation function value that is dependent on the impedances of the first and the second components. A gradient vector calculating unit calculates a gradient vector based on the difference between the evaluation function values before and after the impedance change of the second components. Based on the gradient vector, impedance of each of the first components is changed such that the evaluation function value takes a desired value.Type: ApplicationFiled: January 27, 2005Publication date: July 7, 2005Inventors: Takeshi Toda, Takeshi Takano, Yuuta Nakaya, Yasuyuki Oishi
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Patent number: 6907085Abstract: First, a digital section constituting a linearizer is activated. Then, a feedback loop for updating a distortion compensation coefficient is opened. Then, the analog section on the antenna side is activated from an ADC, including a PA, etc., or a DAC. Then, both the ATT value of an ATT installed in a feedback route for updating the distortion compensation coefficient and the signal delay amount of a signal delay unit are adjusted to make a state such that the distortion compensation coefficient can be accurately updated. Then, the feedback loop is closed, a distortion compensation table having the distortion compensation coefficient as an entry is generated and after the generation is completed, the operation shifts to the normal operation.Type: GrantFiled: March 14, 2001Date of Patent: June 14, 2005Assignee: Fujitsu LimitedInventors: Tokuro Kubo, Takayoshi Ode, Kazuo Nagatani, Hajime Hamada, Hiroyoshi Ishikawa, Yasuyuki Oishi
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Publication number: 20050101258Abstract: A distortion compensation apparatus of the present invention is used in a transmitter that produces and outputs a second signal from a first signal. This apparatus comprises a delay unit for delaying a feedback signal obtained from by the second signal; and a delay control unit for determining a delay quantity of said delay means so that a timing difference between a reference signal obtained from the first signal and the feedback signal delayed by the delay unit is made small. The delay control unit limits the delay quantity within a predetermined limit value.Type: ApplicationFiled: November 23, 2004Publication date: May 12, 2005Inventors: Tokuro Kubo, Kazuo Nagatani, Hajime Hamada, Hiroyoshi Ishikawa, Nobukazu Fudaba, Yasuyuki Oishi, Toru Maniwa, Hiroyuki Hayashi
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Publication number: 20050073361Abstract: The distortion compensator which compensates the nonlinearity of a power amplifier in a radio communication device stops the operation of updating the automatic phase adjustment, automatic delay adjustment, equalizer adjustment, and distortion compensation table when something wrong is detected in the input to a distortion compensation unit such as a reference signal, feedback signal, address of the distortion compensation table, and phase value so that the distortion compensation coefficients may not be improperly updated.Type: ApplicationFiled: November 30, 2004Publication date: April 7, 2005Inventors: Hajime Hamada, Hiroyoshi Ishikawa, Kazuo Nagatani, Tokuro Kubo, Nobukazu Fudaba, Yasuyuki Oishi, Toru Maniwa, Hiroyuki Hayashi
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Publication number: 20050058220Abstract: Disclosed is an adaptive control apparatus having an error calculation unit for calculating the difference between a reference signal and a feedback signal, and an adaptive controller for applying adaptive control so as to diminish the difference and causing the result of adaptive control to be reflected in the reference signal. The adaptive control apparatus has a delay unit for delaying at least one of the reference signal and feedback signal by a set delay time in such a manner that the reference signal and feedback signal will be input simultaneously to the arithmetic unit; a frequency-component detecting unit for detecting a frequency component of the reference signal; a delay-time acquisition unit for acquiring delay time conforming to the frequency component; and a delay-time setting unit for setting the acquired delay time in the delay unit.Type: ApplicationFiled: October 26, 2004Publication date: March 17, 2005Inventors: Kazuo Nagatani, Tokuro Kubo, Hiroyoshi Ishikawa, Yasuyuki Oishi, Toru Maniwa, Hiroyuki Hayashi, Hajime Hamada, Nobukazu Fudaba
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Patent number: 6864745Abstract: In a distortion compensation device which uses distortion compensation coefficients to subject distortion compensation processing to an input signal and supply the result of the distortion compensation processing to a distorting device, calculates the distortion compensation coefficients based on the input signal before distortion compensation and the feedback signal fed back from the output side of the distorting device, and stores the calculated distortion compensation coefficients in association with the input signal, (1) the feedback signal is AD-converted; (2) the AD-converted output is subjected to fast Fourier transform (FFT) processing; (3) the FFT calculation result is used to calculate the value of either the signal-to-noise ratio SNR, or the adjacent channel leakage power ratio ACLR, or the noise level; (4) the delay time occurring in the distorting device and feedback loop is adjusted such that the difference between the above calculated value at the current time and the above calculated value atType: GrantFiled: October 15, 2003Date of Patent: March 8, 2005Assignee: Fujitsu LimitedInventors: Takayoshi Ode, Yasuyuki Oishi, Tokuro Kubo, Kazuo Nagatani, Hajime Hamada, Hiroyoshi Ishikawa, Nobukazu Fudaba
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Patent number: 6864839Abstract: Disclosed is a method of controlling direction of radio-wave emission of a base-station transmitter which emits radio waves upon providing the radio waves with directivity in the direction of a receiver. Two antennas of a base station that are disposed at different positions transmit first and second signals that have been spread by mutually orthogonal spreading codes. A mobile station has a phase detector for receiving the first and second signals transmitted from respective ones of the antennas and obtaining a phase difference between these signals, and a direction estimator for calculating the direction of the mobile station, as seen from the base station, based upon the phase difference and for feeding back a signal representing the calculated direction from the mobile station to the base station. The transmitter of the base station transmits data toward the receiver in the calculated direction using a directional antenna.Type: GrantFiled: April 14, 2003Date of Patent: March 8, 2005Assignee: Fujitsu LimitedInventors: Hajime Hamada, Michiharu Nakamura, Yasuyuki Oishi