Patents by Inventor Koutaro Mizuno
Koutaro Mizuno 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: 9203667Abstract: A circuit and a method for removing a frequency offset and a communication apparatus including the circuit, capable of removing the frequency offset by tracking rapidly and accurately in a payload section. A sequence of sample levels is obtained by sampling a frequency level of the baseband signal at every 0.5 symbol interval. Absolute values of differences between the frequency levels adjacent to each other at every 1 symbol are calculated as first difference absolute values. Absolute values of differences between the frequency levels adjacent to each other at every 1 symbol are calculated as second difference absolute values. When the first difference absolute values are greater than a predetermined first determination value or the second difference absolute values are less than a predetermined second determination value, the average value calculated is set as the frequency offset.Type: GrantFiled: September 18, 2014Date of Patent: December 1, 2015Assignee: LAPIS Semiconductor Co., Ltd.Inventor: Koutaro Mizuno
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Publication number: 20150003568Abstract: A circuit and a method for removing a frequency offset and a communication apparatus including the circuit, capable of removing the frequency offset by tracking rapidly and accurately in a payload section. A sequence of sample levels is obtained by sampling a frequency level of the baseband signal at every 0.5 symbol interval. Absolute values of differences between the frequency levels adjacent to each other at every 1 symbol are calculated as first difference absolute values. Absolute values of differences between the frequency levels adjacent to each other at every 1 symbol are calculated as second difference absolute values. When the first difference absolute values are greater than a predetermined first determination value or the second difference absolute values are less than a predetermined second determination value, the average value calculated is set as the frequency offset.Type: ApplicationFiled: September 18, 2014Publication date: January 1, 2015Applicant: LAPIS SEMICONDUCTOR CO., LTDInventor: Koutaro MIZUNO
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Patent number: 8867669Abstract: A circuit and a method for removing a frequency offset and a communication apparatus including the circuit, capable of removing the frequency offset by tracking rapidly and accurately in a payload section. A sequence of sample levels is obtained by sampling a frequency level of the baseband signal at every 0.5 symbol interval. Absolute values of differences between the frequency levels adjacent to each other at every 1 symbol are calculated as first difference absolute values. Absolute values of differences between the frequency levels adjacent to each other at every 1 symbol are calculated as second difference absolute values. When the first difference absolute values are greater than a predetermined first determination value or the second difference absolute values are less than a predetermined second determination value, the average value calculated is set as the frequency offset.Type: GrantFiled: December 4, 2012Date of Patent: October 21, 2014Assignee: LAPIS Semiconductor Co., Ltd.Inventor: Koutaro Mizuno
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Patent number: 7532064Abstract: A demodulator circuit for demodulating a signal modulated by frequency shift keying discriminates the frequency of the signal to produce demodulated data. When the demodulated data match a known synchronization pattern, or are complementary to the known synchronization pattern, the demodulator circuit latches a value indicating whether the demodulated data match or are complementary to the synchronization pattern. If the latched signal indicates matching data, subsequent demodulated data are output as is. If the latched signal indicates complementary data, subsequent demodulated data are inverted and the inverted data are output. The output data are therefore correct even if the demodulated data are inverted.Type: GrantFiled: July 17, 2007Date of Patent: May 12, 2009Assignee: Oki Semiconductor Co., Ltd.Inventor: Koutaro Mizuno
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Patent number: 7477680Abstract: A de-spreading device for a spread spectrum communication system includes a first and a second correlator assigned to a regular and a power-saving operation mode, respectively. The first correlator performs sampling with a regular operational clock while the second correlator performs sampling with an operational clock higher in rate than the regular operational clock for thereby saving power. The regular or the power-saving operation mode is selected in accordance with radio channel quality estimated on the basis of a peak value detected from a correlation value, which is output from the first or the second correlator. De-spreading can therefore be implemented by an optimum operational clock matching with radio channel quality while consuming a minimum of current.Type: GrantFiled: April 25, 2005Date of Patent: January 13, 2009Assignee: Oki Semiconductor Co., Ltd.Inventor: Koutaro Mizuno
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Patent number: 7477679Abstract: A simplified spread spectrum demodulator uses a frequency detector to demodulate a modulated spread spectrum signal to obtain successive chip values. A correlation unit correlates the successive chip values with fixed sequences of correlation coefficients to generate correlation values. A decision circuit selects one of the correlation values to decide what symbol the spread spectrum signal represents. The correlation coefficients are obtained by applying the same modulation method as used to modulate the spread spectrum signal, and then the same demodulation method as used by the frequency detector, to the sequences of chips representing different symbols. Since synchronous detection is not employed, no carrier recovery circuit is needed.Type: GrantFiled: November 9, 2004Date of Patent: January 13, 2009Assignee: Oki Semiconductor Co., Ltd.Inventor: Koutaro Mizuno
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Publication number: 20080074181Abstract: A demodulator circuit for demodulating a signal modulated by frequency shift keying discriminates the frequency of the signal to produce demodulated data. When the demodulated data match a known synchronization pattern, or are complementary to the known synchronization pattern, the demodulator circuit latches a value indicating whether the demodulated data match or are complementary to the synchronization pattern. If the latched signal indicates matching data, subsequent demodulated data are output as is. If the latched signal indicates complementary data, subsequent demodulated data are inverted and the inverted data are output. The output data are therefore correct even if the demodulated data are inverted.Type: ApplicationFiled: July 17, 2007Publication date: March 27, 2008Applicant: OKI ELECTRIC INDUSTRY CO., LTD.Inventor: Koutaro Mizuno
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Patent number: 7298202Abstract: An FSK demodulator which outputs an enable signal in response to the detection of a data change point in a detected signal of an amplitude associated with the received frequency of an input FSK signal, outputs an average signal of the detected signal for each predetermined time period, acquires the average signal in response to the enable signal to output as an offset signal an average value of M average signals, and subtracts the offset signal from the detected signal to output the resulting signal.Type: GrantFiled: February 23, 2006Date of Patent: November 20, 2007Assignee: Oki Electric Industry Co., Ltd.Inventor: Koutaro Mizuno
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Patent number: 7286615Abstract: A detector includes a binarizer for binarizing the amplitude of an input FSK signal; a 2n-stage shift register having 2n registers for sequentially shifting the FSK signal binarized by the binarizer in response to a clock; and an adder for calculating a sum of a total number of FSK signals having the value of “1” or “0” among FSK signals stored in a first to an n-th register of the 2n-stage shift register and a total number of FSK signals having the value of “0” or “1” among FSK signals stored in an (n+1)th to a 2n-th register.Type: GrantFiled: June 3, 2004Date of Patent: October 23, 2007Assignee: Oki Electric Industry Co., Ltd.Inventor: Koutaro Mizuno
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Publication number: 20060261883Abstract: An FSK demodulator which outputs an enable signal in response to the detection of a data change point in a detected signal of an amplitude associated with the received frequency of an input FSK signal, outputs an average signal of the detected signal for each predetermined time period, acquires the average signal in response to the enable signal to output as an offset signal an average value of M average signals, and subtracts the offset signal from the detected signal to output the resulting signal.Type: ApplicationFiled: February 23, 2006Publication date: November 23, 2006Applicant: OKI ELECTRIC INDUSTRY CO., LTD.Inventor: Koutaro Mizuno
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Publication number: 20060018370Abstract: A de-spreading device for a spread spectrum communication system includes a first and a second correlator assigned to a regular and a power-saving operation mode, respectively. The first correlator performs sampling with a regular operational clock while the second correlator performs sampling with an operational clock higher in rate than the regular operational clock for thereby saving power. The regular or the power-saving operation mode is selected in accordance with radio channel quality estimated on the basis of a peak value detected from a correlation value, which is output from the first or the second correlator. De-spreading can therefore be implemented by an optimum operational clock matching with radio channel quality while consuming a minimum of current.Type: ApplicationFiled: April 25, 2005Publication date: January 26, 2006Applicant: Oki Electric Industry Co., LtdInventor: Koutaro Mizuno
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Publication number: 20050157777Abstract: A simplified spread spectrum demodulator uses a frequency detector to demodulate a modulated spread spectrum signal to obtain successive chip values. A correlation unit correlates the successive chip values with fixed sequences of correlation coefficients to generate correlation values. A decision circuit selects one of the correlation values to decide what symbol the spread spectrum signal represents. The correlation coefficients are obtained by applying the same modulation method as used to modulate the spread spectrum signal, and then the same demodulation method as used by the frequency detector, to the sequences of chips representing different symbols. Since synchronous detection is not employed, no carrier recovery circuit is needed.Type: ApplicationFiled: November 9, 2004Publication date: July 21, 2005Applicant: Oki Electric Industry Co., Ltd.Inventor: Koutaro Mizuno
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Publication number: 20050105653Abstract: A detector includes a binarizer for binarizing the amplitude of an input FSK signal; a 2n-stage shift register having 2n registers for sequentially shifting the FSK signal binarized by the binarizer in response to a clock; and an adder for calculating a sum of a total number of FSK signals having the value of “1” or “0” among FSK signals stored in a first to an n-th register of the 2n-stage shift register and a total number of FSK signals having the value of “0” or “1” among FSK signals stored in an (n+1)th to a 2n-th register.Type: ApplicationFiled: June 3, 2004Publication date: May 19, 2005Applicant: Oki Electric Industry Co., Ltd.Inventor: Koutaro Mizuno