Patents by Inventor Hajime Hamada

Hajime Hamada 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: 20010020917
    Abstract: 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: Application
    Filed: December 21, 2000
    Publication date: September 13, 2001
    Applicant: FUJITSU LIMITED
    Inventors: Hajime Hamada, Michiharu Nakamura, Yasuyuki Oishi
  • Patent number: 6275520
    Abstract: A pseudo-noise generating apparatus capable of starting a pseudo-noise sequence from an arbitrary phase using compact processing circuitry. Tap selection patterns corresponding to a plurality of phase shift amounts are stored in advance in a ROM. By giving a phase shift amount to the ROM and setting the corresponding tap selection pattern in AND gates, the pseudo-noise sequence generated by the pseudo-noise generator is shifted in phase, and is loaded into a shift register. After setting a new phase amount in the ROM, the contents of the shift register are transferred into a shift register in the pseudo-noise generator. By repeating this operation, the desired phase shift is accomplished as a sum of a plurality of phase shift amounts.
    Type: Grant
    Filed: November 23, 1998
    Date of Patent: August 14, 2001
    Assignee: Fujitsu Limited
    Inventors: Takaharu Nakamura, Kazuo Kawabata, Kazuhisa Obuchi, Hajime Hamada
  • Publication number: 20010007435
    Abstract: 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: Application
    Filed: December 14, 2000
    Publication date: July 12, 2001
    Applicant: FUJITSU LIMITED
    Inventors: Takayoshi Ode, Yasuyuki Oishi, Tokuro Kubo, Kazuo Nagatani, Hajime Hamada, Hiroyoshi Ishikawa
  • Patent number: 6198731
    Abstract: There are disclosed a radiocommunication apparatus and a radiocommunication system. There are provided a receiving section capable of receiving a plurality of types of signals which have been spread through use of different spread code information according to a CDMA scheme in a transmitting-side radiocommunication apparatuses; and a spread demodulation section which carries out despread processing for the common signal portions of the plurality of types of signals received by the receiving section through use of a composite spread code formed from a plurality of spread codes. Accordingly, it becomes possible to significantly improve the quality of received signals.
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: March 6, 2001
    Assignee: Fujitsu Limited
    Inventors: Hajime Hamada, Yasuyuki Oishi, Kazuo Nagatani, Hidenobu Fukumasa, Yoshihiko Asano
  • Patent number: 6097714
    Abstract: A code multiplexing transmitting apparatus spread-spectrum modulates transmission data of a plurality of channels by spreading codes that differ from one another, combines the spread-spectrum signals of each of the channels and transmits the resultant spread-spectrum modulated signal. A spread-spectrum modulating unit for each channel includes a phase shifter for shifting, by a predetermined angle channel by channel, the phase of a position vector of the spread-spectrum modulated signal of each channel. As the result of such phase control, the phases of pilot signal portions of the spread-spectrum modulated signals of the respective channels are shifted relative to one another so that the peak values of the code-multiplexed signal can be suppressed.
    Type: Grant
    Filed: June 10, 1997
    Date of Patent: August 1, 2000
    Assignee: Fujitsu Limited
    Inventors: Kazuo Nagatani, Yasuyuki Oishi, Hidenobu Fukumasa, Hajime Hamada, Yoshihiko Asano
  • Patent number: 6058138
    Abstract: A radio receiver includes a plurality of demodulating units for demodulating a received radio wave received via a plurality of paths so as to produce respective demodulated signals, and combining units for executing a combination process of synchronizing and combining the demodulated signals produced by the plurality of demodulating units, the combining units correlating the demodulated signals produced by the plurality of demodulating units and excluding from a combination process a demodulated signal that meets a predetermined condition based on a predetermined algorithm.
    Type: Grant
    Filed: June 6, 1997
    Date of Patent: May 2, 2000
    Assignee: Fujitsu Limited
    Inventors: Hidenobu Fukumasa, Yasuyuki Oishi, Kazuo Nagatani, Hajime Hamada
  • Patent number: 6041034
    Abstract: Co-channel interference may be prevented even if data having different transmission rates are concurrently multiplied to a same frequency band width with a different spreading factors.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: March 21, 2000
    Assignee: Fujitsu Limited
    Inventors: Hidenobu Fukumasa, Yasuyuki Oishi, Kazuo Nagatani, Hajime Hamada
  • Patent number: 6028894
    Abstract: SIR measurement for measuring S/N ratio, which is the ratio of a desired signal power to noise power, or S/I ratio, which is the ratio of desired signal power to interference signal power, uses a signal-point position altering unit for taking absolute values of an I component (in-phase component) and Q component (quadrature component) of a received signal to convert the received signal to a signal in the first quadrant of an I-Q orthogonal coordinate system, and for squaring the average value of the converted signal to obtain first average power (desired power) S, a received-power arithmetic unit for calculating the average value of the square of the received signal to obtain second average power, and for subtracting the desired power S from the received power to obtain noise power or interference power I, and a SIR arithmetic unit for calculating S/N ratio or S/I ratio from the desired signal power S and noise power or interference signal power I, and for outputting the ratio calculated.
    Type: Grant
    Filed: September 4, 1997
    Date of Patent: February 22, 2000
    Assignee: Fujitsu Limited
    Inventors: Yasuyuki Oishi, Kazuo Nagatani, Hidenobu Fukumasa, Hajime Hamada, Yoshihiko Asano
  • Patent number: 6009090
    Abstract: A code multiplexing wireless apparatus for amplifying a code-multiplexed signal and then transmitting the amplified signal includes the following to reduce output back-off, improve the efficiency of a power amplifier and suppress broadening of the frequency spectrum: (1) a code-multiplexed signal generator for multiplying each item of transmission data by a spreading code sequence and combining spread-spectrum modulated signals to generate a code-multiplexed signal, (2) a signal-peak suppressing unit for holding the envelope of the code-multiplexed signal below a set level, and (3) a power amplifier for amplifying the code-multiplexed signal and transmitting the amplified code-multiplexed signal from an antenna.
    Type: Grant
    Filed: June 10, 1997
    Date of Patent: December 28, 1999
    Assignee: Fujitsu Limited
    Inventors: Yasuyuki Oishi, Kazuo Nagatani, Hidenobu Fukumasa, Hajime Hamada, Yoshihiko Asano
  • Patent number: 5999579
    Abstract: In order to avoid a floor phenomenon of an error rate without insertion of a datum signal, a fading equalizer, for which it is assumed that a series of symbols that represent quadrature detect output are I(n) and Q(n) (n: natural number) and an assumed maximum fading frequency is F(max), and which demodulates a modulation wave that is to be transmitted whose data are carried by phase or amplitude modulation, or both, of a radio frequency carrier, includes a symbol extractor, for performing sampling of a signal at time intervals of 1/(2 F.sub.max) or smaller, in accordance with the series of symbols; N fading estimation units, for calculating a series of fading vectors F.sub.
    Type: Grant
    Filed: November 7, 1996
    Date of Patent: December 7, 1999
    Assignee: Fujitsu Limited
    Inventors: Makoto Uchishima, Hajime Hamada
  • Patent number: PP4674
    Abstract: A nectarine tree broadly bearing yellow-fleshed fruit of large size and resembling the Sun Grand Variety (U.S. Plant Pat. No. 974), but which bears fruit which attains an overall red coloration without exposure to sun, which ripens evenly, and which ripens about one week earlier than that of the Sun Grand.
    Type: Grant
    Filed: November 23, 1979
    Date of Patent: March 17, 1981
    Assignees: Robert M. Hamada, Lindsay K. Hamada
    Inventor: Hajime Hamada