Patents by Inventor Seiji Okubo

Seiji Okubo 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).

  • Patent number: 7970076
    Abstract: A wireless apparatus which performs a frequency conversion on a received signal with a mixer and an analog filter, and which corrects for distortion of the received signal, which occurs because the analog filter is not an ideal one, using a digital filter disables the filtering of the received signal by the digital filter when determining from the reception power level (or reception amplitude level) of the received signal that the filtering of the received signal by the digital filter will increase the distortion of the received signal.
    Type: Grant
    Filed: April 27, 2004
    Date of Patent: June 28, 2011
    Assignee: Mitsubishi Electric Corporaiton
    Inventors: Taisei Suemitsu, Hiroyasu Sano, Seiji Okubo, Kentaro Gotou
  • Publication number: 20070140381
    Abstract: A wireless apparatus which performs a frequency conversion on a received signal with a mixer and an analog filter, and which corrects for distortion of the received signal, which occurs because the analog filter is not an ideal one, using a digital filter disables the filtering of the received signal by the digital filter when determining from the reception power level (or reception amplitude level) of the received signal that the filtering of the received signal by the digital filter will increase the distortion of the received signal.
    Type: Application
    Filed: April 27, 2004
    Publication date: June 21, 2007
    Applicant: Mitsubishi Electric Corporation
    Inventors: Taisei Suemitsu, Hiroyasu Sano, Seiji Okubo, Kentaro Gotou
  • Patent number: 7225883
    Abstract: The invention relates to a device for a coupling an agricultural implement to an agricultural tractor, in which the operation to release the coupling between the agricultural implement and the agricultural tractor can be easily implemented. When the coupling of the agricultural tractor and the agricultural implement is released, first, a control lever of a coupling hook is slid upward against the urging force of a spring until a second guide pin reaches the lower end of a slit. Next, the control lever is turned forward around the second guide pin until a bent portion of the upper portion and the lower portion of the control lever comes into contact with a first guide pin. As a result, the rear end of a stopper is retracted into a cavity in the hook main body of the device through a second opening so as to slide to the coupling-ball-releasing position, and a groove of the stopper is hooked to a hooking pin so as to be fixed.
    Type: Grant
    Filed: February 11, 2005
    Date of Patent: June 5, 2007
    Assignee: Kabushiki Kaisha DELICA
    Inventors: Shoichi Yamada, Takao Yamamoto, Seiji Okubo
  • Patent number: 7095778
    Abstract: A spread spectrum transmitter provides delays having different magnitudes to spread spectrum (SS) signals for a plurality of channels, and multiplexes the SS signals to generate transmission multiplex SS signal. A spread spectrum receiver calculates a partial correlation value between the transmission multiplex SS signal and spreading codes multiplied to the SS signals, multiplies the partial correlation values by a prescribed matrix prepared based on each orthogonal code sequence to calculate a plurality of orthogonal correlation values. The receiver identifies for a respective channel each parallel data sequence related in advance to an orthogonal code sequence whose orthogonal correlation value is a maximum, corrects delay differences of the parallel data sequences, and then performs sampling and parallel-serial conversion to obtain a serial demodulated data sequence.
    Type: Grant
    Filed: January 2, 2003
    Date of Patent: August 22, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Seiji Okubo, Tatsuya Uchiki, Toshiharu Kojima
  • Publication number: 20060005977
    Abstract: The invention relates to a device for a coupling an agricultural implement to an agricultural tractor, in which the operation to release the coupling between the agricultural implement and the agricultural tractor can be easily implemented. When the coupling of the agricultural tractor and the agricultural implement is released, first, a control lever of a coupling hook is slid upward against the urging force of a spring until a second guide pin reaches the lower end of a slit. Next, the control lever is turned forward around the second guide pin until a bent portion of the upper portion and the lower portion of the control lever comes into contact with a first guide pin. As a result, the rear end of a stopper is retracted into a cavity in the hook main body of the device through a second opening so as to slide to the coupling-ball-releasing position, and a groove of the stopper is hooked to a hooking pin so as to be fixed.
    Type: Application
    Filed: February 11, 2005
    Publication date: January 12, 2006
    Applicant: KABUSHIKI KAISHA DELICA
    Inventors: Shoichi Yamada, Takao Yamamoto, Seiji Okubo
  • Patent number: 6940892
    Abstract: A spread spectrum transmission apparatus includes, a chip clock generation section which outputs a chip clock in one frame formed of M+L?1 chips, a frame clock generation section which outputs a frame clock synchronized to frame occurrence timing, SS-PPM signal generation sections each of which inserts a pseudonoise code sequence corresponding to one period from some of M chips located at a head of a frame based on K-bit transmission data and generates an SS-PPM signal, delay sections which respectively delay N SS-PPM signals respectively by determined delay quantities, and a multiplexing section which adds up all of outputs respectively of the delay units and generates a multiplexed SS-PPM signal.
    Type: Grant
    Filed: March 14, 2002
    Date of Patent: September 6, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Seiji Okubo, Tatsuya Uchiki, Toshiharu Kojima
  • Patent number: 6850576
    Abstract: A base band signal is sampled, based on an asynchronous sampling clocking, to output two sampled data series. A transmission side complex symbol frequency generator generates a complex transmission symbol frequency component combining an envelope value and an amplitude change amount value, which are each calculated from the two sampled data series. The transmission side complex symbol frequency component is provided to a correlation value calculator that outputs a correlation data series correlated to the complex symbol frequency and the symbol frequency generated by a cosine wave generator. The correlation data series is converted a timing error by an inverse tangent calculator. By the above configuration, a timing reproducing unit, which includes the above components, determines the timing error at a sampling speed of twice the symbol rate.
    Type: Grant
    Filed: February 5, 2001
    Date of Patent: February 1, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Akinori Fujimura, Seiji Okubo, Toshiharu Kojima
  • Patent number: 6728298
    Abstract: There are provided a spread code generating section generates a spread code list from the input parallel information, spread modulating sections generate a plurality of parallel spectrum spread signals corresponding to the parallel information list by multiplying each of the parallel information list and the spread code list respectively, phase shifting sections shift the phase of the parallel spectrum spread signals, delay sections delay the parallel spectrum spread signals. A multiplexing section generates a multiplexed spectrum spread signal by adding the delayed parallel spectrum spread signals. The multiplexed spectrum spread signal are converted into a radio frequency signal, amplified and then transmitted.
    Type: Grant
    Filed: March 3, 2000
    Date of Patent: April 27, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Seiji Okubo, Akinori Fujimura, Toshiharu Kojima
  • Patent number: 6683493
    Abstract: In-phase and orthogonal components of a base band signal having a preamble symbol are squared to obtain squared in-phase orthogonal components. Amount of correlation is obtained between the squared in-phase component and a ½ symbol frequency component output from a VCO or an oscillator, and amount of correlation is obtained between the squared orthogonal component and the ½ symbol frequency component. Finally, a phase control signal for carrying out a phase control is generated by using the obtained amount of correlations.
    Type: Grant
    Filed: August 23, 2001
    Date of Patent: January 27, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Akinori Fujimora, Seiji Okubo, Toshiharu Kojima
  • Patent number: 6650718
    Abstract: A timing recovery device and demodulator. An adding device adds together an in-phase component and a quadrature component of a base band signal. A subtracting device subtracts the in-phase component and the quadrature component of the base band signal from each other. Then, the correlation between the added signal and a ½ symbol frequency component generated at the receiver side and the correlation between the subtracted value and the ½ symbol frequency component are calculated. A vector selector compares the added value correlation signal and the subtracted value correlation signal, and selects the larger one of the correlation signals. A timing phase difference calculator then calculates a timing phase difference, using the vector angle indicated by the selected correlation signal.
    Type: Grant
    Filed: August 28, 2001
    Date of Patent: November 18, 2003
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Akinori Fujimura, Seiji Okubo, Toshiharu Kojima
  • Publication number: 20030138031
    Abstract: A spread spectrum transmitter provides delays having different magnitudes to spread spectrum (SS) signals for a plurality of channels, and multiplexes the SS signals to generate transmission multiplex SS signal. A spread spectrum receiver calculates a partial correlation value between the transmission multiplex SS signal and spreading codes multiplied to the SS signals, multiplies the partial correlation values by a prescribed matrix prepared based on each orthogonal code sequence to calculate a plurality of orthogonal correlation values. The receiver identifies for a respective channel each parallel data sequence related in advance to an orthogonal code sequence whose orthogonal correlation value is a maximum, corrects delay differences of the parallel data sequences, and then performs sampling and parallel-serial conversion to obtain a serial demodulated data sequence.
    Type: Application
    Filed: January 2, 2003
    Publication date: July 24, 2003
    Inventors: Seiji Okubo, Tatsuya Uchiki, Toshiharu Kojima
  • Patent number: 6522684
    Abstract: In a DLL, in-phase correlation signal and orthogonal correlation signal are squared and adder to generate correlation power. Delays are provided so that the peaks of N number of divided correlation power portions to have coincided timing with each other. Composite correlation power is generated from the respective correlation power portions. A composite error signal of a sample clock is generated by subtracting the composite correlation power from the composite correlation power that has been delayed. A data clock is generated by frequency-dividing the sample clock based upon an acquisition pulse. A sample clock is finally generated based upon the composite error signal that has been latched and noise-removed therefrom in synchronized timing with the data clock that has been delayed.
    Type: Grant
    Filed: February 8, 2001
    Date of Patent: February 18, 2003
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Seiji Okubo, Toshiharu Kojima, Akinori Fujimura
  • Publication number: 20020176486
    Abstract: A spread spectrum transmission apparatus includes, a chip clock generation section which outputs a chip clock in one frame formed of M+L−1 chips, a frame clock generation section which outputs a frame clock synchronized to frame occurrence timing, SS-PPM signal generation sections each of which inserts a pseudonoise code sequence corresponding to one period from some of M chips located at a head of a frame based on K-bit transmission data and generates an SS-PPM signal, delay sections which respectively delay N SS-PPM signals respectively by determined delay quantities, and a multiplexing section which adds up all of outputs respectively of the delay units and generates a multiplexed SS-PPM signal.
    Type: Application
    Filed: March 14, 2002
    Publication date: November 28, 2002
    Inventors: Seiji Okubo, Tatsuya Uchiki, Toshiharu Kojima
  • Patent number: 6456672
    Abstract: In a communication system using the time diversity transmission scheme, the communication system provided with the stable automatic frequency control circuit with the wide frequency pull-in range and under low CN ratio transmission is achieved by removing the modulation phase from the received data through the application of the data correlation of the time diversity.
    Type: Grant
    Filed: April 28, 1998
    Date of Patent: September 24, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuya Uchiki, Toshiharu Kojima, Hiroyasu Sano, Seiji Okubo, Makoto Miyake
  • Publication number: 20020085652
    Abstract: In the automatic frequency control apparatus, a correlation between a complex spectrum spread signal and a spread code is computed to output a complex correlation signal. A sample clock for sampling the complex spectrum spread signal and a data clock synchronous with a repetitive period of the spread code are generated based on the complex correlation signal. Delay correcting sections correct the delays so that generation timings of the correlation peak values with respect to each parallel transmission signal of each of the complex correlation signals divided to N signals. Latch sections latch the correlation peak value using a data clock and a synthetic frequency error signal generating section for generating a synthetic frequency error signal based on each signal. Frequency offset of the local carrier is corrected based on the synthetic frequency error signal.
    Type: Application
    Filed: November 6, 2001
    Publication date: July 4, 2002
    Inventors: Seiji Okubo, Toshiharu Kojima
  • Publication number: 20010033602
    Abstract: In a DLL, in-phase correlation signal and orthogonal correlation signal are squared and adder to generate correlation power. Delays are provided so that the peaks of N number of divided correlation power portions to have coincided timing with each other. Composite correlation power is generated from the respective correlation power portions. A composite error signal of a sample clock is generated by subtracting the composite correlation power from the composite correlation power that has been delayed. A data clock is generated by frequency-dividing the sample clock based upon an acquisition pulse. A sample clock is finally generated based upon the composite error signal that has been latched and noise-removed therefrom in synchronized timing with the data clock that has been delayed.
    Type: Application
    Filed: February 8, 2001
    Publication date: October 25, 2001
    Inventors: Seiji Okubo, Toshiharu Kojima, Akinori Fujimura
  • Publication number: 20010031021
    Abstract: Two A/D converters sample received base band signal Sb by asynchronous sampling clock at double speed of symbol rate, and based on the sampled data series Ii, Qi. A transmission complex symbol frequency generator generates data series Ei, Di of transmission complex symbol frequency component. A correlation value calculator outputs correlation data series SMi as the correlation value of cosine wave data series Ci, and data series Ei, D1 of symbol frequency generated by a cosine wave generator, based on the asynchronous sampling clock CK. An inverse tangent calculator outputs a timing error &tgr; based on the correlation data series SMi.
    Type: Application
    Filed: February 5, 2001
    Publication date: October 18, 2001
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA, 2-3, Marunouchi 2-chome, Chiyoda-ku, TOKYO, JAPAN
    Inventors: Akinori Fujimura, Seiji Okubo, Toshiharu Kojima
  • Patent number: 6212222
    Abstract: In the identical spread code multiplex SS system, a delay correction unit and a multiplexer calculates the multiplexed square correlation value by matching the peak values and adding the square correlation values of all the multiplexed signals. The multiplexed signals are the signals obtained by multiplexing an RF signal in such manner that different specific delay times are respectively given to parallel transmission information sequences multiplied by identical spread codes. Therefore, code synchronization can be realized by using only one correlator for both the orthogonal and an in-phase components.
    Type: Grant
    Filed: January 14, 2000
    Date of Patent: April 3, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Seiji Okubo, Akinori Fujimura, Takashi Asahara, Toshiharu Kojima
  • Patent number: 6097766
    Abstract: A demodulator is made compact, and with a simple circuit arrangement, and also having a better bit error rate characteristic. A timing phase synchronization detecting circuit 219 judges any one of the following two conditions based upon baseband phase data 202, i.e., an UNLOCK (timing phase asynchronous) condition, and a LOCK (timing phase synchronous) condition. Based upon the judgement result of the timing phase synchronization detecting circuit 219, in a timing recovering means 221, a frequency range of a PLL (phase synchronization loop) is variable, whereas the number of data entered within 1 symbol time is variable in a frequency synchronizing means 222 and a carrier recovering means 223. A data demodulating means 224 outputs demodulation data 206 in response to baseband phase data 202 and a recovery carrier signal 205.
    Type: Grant
    Filed: October 22, 1998
    Date of Patent: August 1, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Seiji Okubo, Akinori Fujimura, Makoto Miyake
  • Patent number: 4607229
    Abstract: A phase shifter includes first and second mixers which mix a first signal with a second signal having a phase different from the first signal, respectively, third and fourth mixers which mix the second signal with the output signals of the first and second mixers and a combiner which combines the output signals of the third and fourth mixers to produce an output signal having a phase which is inverted with respect to the first signal.
    Type: Grant
    Filed: November 8, 1984
    Date of Patent: August 19, 1986
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Seiji Isobe, Seiji Okubo