Patents by Inventor Kouei Misaizu
Kouei Misaizu 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: 20030067995Abstract: A wireless communication system includes an amplitude limiting section that limits an amplitude of a sequence of signals input for transmission and a nonlinear distortion compensating section compensates nonlinear distortion of the sequence of signals output from the amplitude limiting section. A digital wireless communication method is also provided.Type: ApplicationFiled: October 2, 2001Publication date: April 10, 2003Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., Ltd.Inventors: Akihiko Matsuoka, Masayuki Orihashi, Morikazu Sagawa, Kenichi Takahashi, Kouei Misaizu
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Patent number: 6418173Abstract: Nonlinear distortion compensating data is calculated by approximation equations at a compensating coefficient calculation section using an amplitude value of transmission quadrature base band signals obtained by a power calculating section, wherein by carrying out nonlinear distortion compensation at a nonlinear distortion compensating section using the data, it is possible to compensate nonlinear distortion generated in an amplifier of the transmission system without use of any memory table, and a nonlinear distortion compensating section can be obtained, which has a great effect of decrease distortion.Type: GrantFiled: July 15, 1998Date of Patent: July 9, 2002Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Akihiko Matsuoka, Masayuki Orihashi, Morikazu Sagawa, Kenichi Takahashi, Kouei Misaizu
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Publication number: 20020064236Abstract: Nonlinear distortion compensating data is calculated by approximation equations at a compensating coefficient calculation section using an amplitude value of transmission quadrature base band signals obtained by a power calculating section, wherein by carrying out nonlinear distortion compensation at a nonlinear distortion compensating section using the data, it is possible to compensate nonlinear distortion generated in an amplifier of the transmission system without use of any memory table, and a nonlinear distortion compensating section can be obtained, which has a great effect of decrease distortion.Type: ApplicationFiled: July 15, 1998Publication date: May 30, 2002Inventors: AKIHIKO MATSUOKA, MASAYUKI ORIHASHI, MORIKAZU SAGAWA, KENICHI TAKAHASHI, KOUEI MISAIZU
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Patent number: 6324221Abstract: Nonlinear distortion compensating data is calculated by approximation equations at a compensating coefficient calculation section using an amplitude value of transmission quadrature base band signals obtained by a power calculating section, wherein by carrying out nonlinear distortion compensation at a nonlinear distortion compensating section using the data, it is possible to compensate nonlinear distortion generated in an amplifier of the transmission system without use of any memory table, and a nonlinear distortion compensating section can be obtained, which has a great effect of decrease distortion.Type: GrantFiled: July 15, 1998Date of Patent: November 27, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Akihiko Matsuoka, Masayuki Orihashi, Morikazu Sagawa, Kenichi Takahashi, Kouei Misaizu
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Patent number: 5555247Abstract: In a frame synchronizing apparatus for a receiver apparatus of a digital data radio communications system in which data are transmitted in frame periods with a fixed data sequence contained each frame, a data correlation circuit obtains successive sequences of values of vector difference between vector values constituting a demodulated digital baseband signal, and successively compares these sequences with a fixed vector difference sequence corresponding to the fixed data sequence, to derive a correlation signal substantially unaffected by any phase rotation in the baseband signal. A frame synchronizing circuit formed as a PLL for generating a frame synchronizing signal, includes a phase comparator which periodically indicates whether a detected phase difference between the correlation signal and frame synchronizing signal is effectively zero, positive or negative, and a counter holding a count value indicating a cumulative phase error between these signals.Type: GrantFiled: August 16, 1995Date of Patent: September 10, 1996Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Akihiko Matsuoka, Hiroshi Ohnishi, Yoshinori Kunieda, Kouei Misaizu, Yuuri Yamamoto
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Patent number: 5487089Abstract: An input bit sequence is converted into n-bit parallel symbol signals each representing one symbol. A shift register stores an "m" number of the n-bit parallel symbol signals, shifting the n-bit parallel symbol signals one symbol by one symbol and outputting them. At least one selector is operative for sequentially selecting one of the k-th symbol signal and the (m+1)-k-th symbol signal outputted by the shift register in response to a clock signal, where k equals 1, 2, . . . , (m-1)/2. A sampling counter serves to count pairs of successive clock pulses of the clock signal. An Exclusive-OR circuit executes Exclusive-OR operation between the clock signal and an output signal of the sampling counter. At least one first read-only memory stores data representing portions of predetermined impulse response waveforms, and outputs the data in response to an address signal having higher and lower parts.Type: GrantFiled: February 11, 1993Date of Patent: January 23, 1996Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kouei Misaizu, Shoichiro Honda, Hiroshi Ohnishi
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Patent number: 5463627Abstract: In a frame synchronizing apparatus for a receiver apparatus of a digital data radio communications system in which data are transmitted in frame periods with a fixed data sequence contained each frame, a data correlation circuit obtains successive sequences of values of vector difference between vector values constituting a demodulated digital baseband signal, and successively compares these sequences with a fixed vector difference sequence corresponding to the fixed data sequence, to derive a correlation signal substantially unaffected by any phase rotation in the baseband signal. A frame synchronizing circuit formed as a PLL for generating a frame synchronizing signal, includes a phase comparator which periodically indicates whether a detected phase difference between the correlation signal and frame synchronizing signal is effectively zero, positive or negative, and a counter holding a count value indicating a cumulative phase error between these signals.Type: GrantFiled: February 23, 1994Date of Patent: October 31, 1995Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Akihiko Matsuoka, Hiroshi Ohnishi, Yoshinori Kunieda, Kouei Misaizu, Yuuri Yamamoto
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Patent number: 5448197Abstract: A frequency conversion circuit for mixing first and second frequency signals to supply an output frequency signal comprises: first and second FETs having first and second gates for receiving the first and second frequency signals respectively; and a third FET having a third gate ac-grounded, the first to third FETs being connected in series such that a current flowing through the current circuit between the source and drain is controlled by the first to third gates, the third FET being provided between the first and second FETs. The third FET may also be provided between connection an end of the series connector and the second FET in accordance with frequency differences between the first and second frequency signals and between the second frequency signal and the output frequency signal. A triple gate FET can be used in place of these three FETs connected in series. A quad gate FET can be used also. A mixing circuit including the frequency conversion circuit mentioned above is also disclosed.Type: GrantFiled: February 4, 1994Date of Patent: September 5, 1995Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Morikazu Sagawa, Kazuaki Takahashi, Kouei Misaizu, Makoto Takemoto
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Patent number: 5335251Abstract: A diversity receiver includes a first antenna and a second antenna. A first receiving section connected to the first antenna serves to convert a digital modulation wave induced at the first antenna into a first intermediate-frequency signal. A first band pass filter connected to the first receiving section serves to subject the first intermediate-frequency signal to a band pass filtering process. A second receiving section connected to the second antenna serves to convert a digital modulation wave induced at the second antenna into a second intermediate-frequency signal. A second band pass filter connected to the second receiving section serves to subject the second intermediate-frequency signal to a band pass filtering process. A switch alternately selects one of output signals of the first and second band pass filters at a period equal to a half of a period corresponding to the symbol rate.Type: GrantFiled: December 22, 1992Date of Patent: August 2, 1994Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Onishi, Akihiko Matsuoka, Kouei Misaizu, Yuuri Yamamoto
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Patent number: 5200977Abstract: A terminal unit apparatus for a time division multiplexing access radio communications system formed of a base station and a number of terminal units remote from the base station, includes a 2-dimensional adaptive equalizer circuit for equalizing two quadrature-relationship baseband signals which are obtained from a received quadrature digital modulation signal during receiving operation of the terminal unit, and an internal signal source which generates a local oscillator signal for use in demodulating a received signal to obtain these baseband signals. A frequency correction quantity is derived from the average rate of variation in each symbol interval of the ratio of the two main tap coefficients of the 2-dimensional adaptive equalizer circuit, and used to correct the frequency of operation of the internal signal source during both receiving operation and also in transmitting operation, in which the internal signal source provides a carrier signal for modulation.Type: GrantFiled: February 25, 1991Date of Patent: April 6, 1993Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Ohnishi, Yuuri Yamamoto, Kouei Misaizu
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Patent number: 5150383Abstract: An asynchronous quadrature demodulator which comprises an asynchronous quadrature detector, a frequency compensating circuit for estimating and compensating a frequency offset between an oscillating frequency of a local oscillator of the asynchronous quadrature detector and a frequency of a received carrier frequency on the basis of correcting signals, a base band complex equalizer for eliminating a transmission-channel distortion due to a multiplex transmission and a data demodulator. Thereby, a reference carrier recovery circuit becomes unnecessary. Thus, the structure of the demodulator can be simplified. Further, the demodulator can stably operate on the transmission channel.Type: GrantFiled: March 7, 1991Date of Patent: September 22, 1992Assignee: Matushita Electric Industrial Co., Ltd.Inventors: Kouei Misaizu, Hiroshi Ohnishi
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Patent number: 4791387Abstract: A microwave band frequency synthesizer comprises first and second phase-locking loops. The first phase-locking loop includes a first voltage controlled oscillator, a variable frequency divider and a first multiplier and generates an output signal whose frequency changes at the rate of a unit frequency change width of the oscillator.Type: GrantFiled: December 15, 1987Date of Patent: December 13, 1988Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Makoto Hasegawa, Kouei Misaizu, Mitsuo Makimoto