Patents by Inventor Taizo Yamawaki

Taizo Yamawaki 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: 9693320
    Abstract: A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.
    Type: Grant
    Filed: January 11, 2017
    Date of Patent: June 27, 2017
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventors: Satoshi Tanaka, Kiichiro Takenaka, Takayuki Tsutsui, Taizo Yamawaki, Shun Imai
  • Publication number: 20170127359
    Abstract: A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.
    Type: Application
    Filed: January 11, 2017
    Publication date: May 4, 2017
    Inventors: Satoshi Tanaka, Kiichiro Takenaka, Takayuki Tsutsui, Taizo Yamawaki, Shun Imai
  • Patent number: 9585105
    Abstract: A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.
    Type: Grant
    Filed: August 19, 2016
    Date of Patent: February 28, 2017
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventors: Satoshi Tanaka, Kiichiro Takenaka, Takayuki Tsutsui, Taizo Yamawaki, Shun Imai
  • Publication number: 20160360495
    Abstract: A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.
    Type: Application
    Filed: August 19, 2016
    Publication date: December 8, 2016
    Inventors: Satoshi Tanaka, Kiichiro Takenaka, Takayuki Tsutsui, Taizo Yamawaki, Shun Imai
  • Patent number: 9451561
    Abstract: A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.
    Type: Grant
    Filed: December 5, 2012
    Date of Patent: September 20, 2016
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventors: Satoshi Tanaka, Kiichiro Takenaka, Takayuki Tsutsui, Taizo Yamawaki, Shun Imai
  • Publication number: 20150089265
    Abstract: The power consumption of a data sampling unit that selects a phase of a clock signal appropriate for sampling payload data is reduced at an input interface. A semiconductor integrated circuit includes an input interface and internal core circuits. The input interface includes a hysteresis circuit and a data sampling unit. The hysteresis circuit detects an input signal between first and second input thresholds as a sleep command. The data sampling unit selects an appropriate phase of a sampling clock signal in accordance with a synchronizing signal and samples payload data. When a sleep command is detected, a sleep signal is also supplied to the internal core circuits and the data sampling unit and they are controlled into a low-power consumption state.
    Type: Application
    Filed: December 2, 2014
    Publication date: March 26, 2015
    Inventors: Hiroshi Kamizuma, Taizo Yamawaki, Yukinori Akamine, Koji Maeda
  • Publication number: 20150011256
    Abstract: A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.
    Type: Application
    Filed: December 5, 2012
    Publication date: January 8, 2015
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Satoshi Tanaka, Kiichiro Takenaka, Takayuki Tsutsui, Taizo Yamawaki, Shun Imai
  • Patent number: 8922263
    Abstract: The power consumption of a data sampling unit that selects a phase of a clock signal appropriate for sampling payload data is reduced at an input interface. A semiconductor integrated circuit includes an input interface and internal core circuits. The input interface includes a hysteresis circuit and a data sampling unit. The hysteresis circuit detects an input signal between first and second input thresholds as a sleep command. The data sampling unit selects an appropriate phase of a sampling clock signal in accordance with a synchronizing signal and samples payload data. When a sleep command is detected, a sleep signal is also supplied to the internal core circuits and the data sampling unit and they are controlled into a low-power consumption state.
    Type: Grant
    Filed: August 14, 2009
    Date of Patent: December 30, 2014
    Assignee: Renesas Electronics Corporation
    Inventors: Hiroshi Kamizuma, Taizo Yamawaki, Yukinori Akamine, Koji Maeda
  • Patent number: 8922407
    Abstract: A reference A/D conversion unit is connected in parallel to an input common to a time-interleaved A/D converter to be a calibration target, and the output of each unitary A/D conversion unit which makes up the time-interleaved A/D converter is calibrated in a digital region by using a low-speed high-resolution A/D conversion result output from the reference A/D conversion unit. Also, fCLK/N (fCLK represents an overall sampling rate of the time-interleaved A/D converter, and N is relatively prime to the number of unitary A/D conversion units connected in parallel M) is set as the operation clock frequency of the reference A/D conversion unit. Samplings of all unitary A/D conversion units can be sequentially synchronized with the sampling of the reference A/D conversion unit, and the operation clock frequency of the reference A/D converter can be made N times slower than the overall sampling rate of the time-interleaved A/D converter.
    Type: Grant
    Filed: April 30, 2014
    Date of Patent: December 30, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Oshima, Taizo Yamawaki, Tomomi Takahashi
  • Publication number: 20140232578
    Abstract: A reference A/D conversion unit is connected in parallel to an input common to a time-interleaved A/D converter to be a calibration target, and the output of each unitary A/D conversion unit which makes up the time-interleaved A/D converter is calibrated in a digital region by using a low-speed high-resolution A/D conversion result output from the reference A/D conversion unit. Also, fCLK/N (fCLK represents an overall sampling rate of the time-interleaved A/D converter, and N is relatively prime to the number of unitary A/D conversion units connected in parallel M) is set as the operation clock frequency of the reference A/D conversion unit. Samplings of all unitary A/D conversion units can be sequentially synchronized with the sampling of the reference A/D conversion unit, and the operation clock frequency of the reference A/D converter can be made N times slower than the overall sampling rate of the time-interleaved A/D converter.
    Type: Application
    Filed: April 30, 2014
    Publication date: August 21, 2014
    Applicant: HITACHI, LTD.
    Inventors: Takashi OSHIMA, Taizo YAMAWAKI, Tomomi TAKAHASHI
  • Patent number: 8736470
    Abstract: A reference A/D conversion unit is connected in parallel to an input common to a time-interleaved A/D converter to be a calibration target, and the output of each unitary A/D conversion unit which makes up the time-interleaved A/D converter is calibrated in a digital region by using a low-speed high-resolution A/D conversion result output from the reference A/D conversion unit. Also, fCLK/N (fCLK represents an overall sampling rate of the time-interleaved A/D converter, and N is relatively prime to the number of unitary A/D conversion units connected in parallel M) is set as the operation clock frequency of the reference A/D conversion unit. Samplings of all unitary A/D conversion units can be sequentially synchronized with the sampling of the reference A/D conversion unit, and the operation clock frequency of the reference A/D converter can be made N times slower than the overall sampling rate of the time-interleaved A/D converter.
    Type: Grant
    Filed: December 28, 2011
    Date of Patent: May 27, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Oshima, Taizo Yamawaki, Tomomi Takahashi
  • Patent number: 8633746
    Abstract: A phase detector, which forms a semiconductor device, detects a phase difference between a reference signal and a feedback signal obtained by feeding back an output signal of an oscillator, and generates a phase difference value indicating a value in accordance with the phase difference. An amplifier amplifies the phase difference value at a gain determined in accordance with a control signal from outside the device. A filter smoothes an output value of the amplifier. The oscillator controls a frequency of the output signal in accordance with an output value of the filter.
    Type: Grant
    Filed: October 17, 2012
    Date of Patent: January 21, 2014
    Assignee: Renesas Mobile Corporation
    Inventors: Takayasu Norimatsu, Satoru Yamamoto, Taizo Yamawaki
  • Patent number: 8494456
    Abstract: The transmitter of the transceiver includes: a transmitter-side mixers of a transmitter-side modulator; a transmitter-side voltage-controlled oscillator; and a transmitter-side divider. The divider having a dividing factor of a non-integral number is supplied with an oscillating output of the oscillator. A pair of non-quadrature local signals having a phase difference of 90° plus a predetermined offset angle is produced by the divider and supplied to the mixers. The transmitter includes a phase-shift unit which converts a pair of quadrature transmit signals having a phase difference of about 90° on an analog basis into a pair of non-quadrature shifted transmit signals. Consequently, quadrature modulation is performed by the mixers. Use of a similar configuration enables the reduction in interference of an RF signal with local signals supplied to receiver-side mixers of the receiver.
    Type: Grant
    Filed: August 23, 2012
    Date of Patent: July 23, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Satoshi Tanaka, Hiroshi Kamizuma, Koji Maeda, Sungwoo Cha, Yukinori Akamine, Taizo Yamawaki
  • Patent number: 8442461
    Abstract: The transmitter synthesizes amplitude and phase components and calibrates a delay mismatch between amplitude and phase components with high accuracy at high speed. The transmitter has: a digital-to-analog converter (DAC) and a low-pass filter (LPF) in its amplitude-signal path; and a phase modulator operable to convert up a phase component into an RF component in its phase-signal path. In an operation of delay calibration, a test input signal is supplied to a delay-calibrating unit in the amplitude-signal path, and the delay-calibrating unit provides a test input signal to DAC. Then, LPF generates a test output signal. The delay-calibrating unit detects a delay of the test output signal relative to the test input signal, calibrates an amplitude signal delay in a range from the input of the delay-calibrating unit to the output of LPF, reduces the difference between amplitude and phase signal delays of the phase modulator in the phase-signal path.
    Type: Grant
    Filed: August 11, 2010
    Date of Patent: May 14, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Takayasu Norimatsu, Taizo Yamawaki, Yukinori Akamine, Koji Maeda
  • Patent number: 8411730
    Abstract: The semiconductor integrated communication circuit includes: a low-noise amplifier; a receive mixer; a receive VCO; a demodulation-processing circuit; a modulation-processing circuit; a transmit mixer; a transmit VCO; a second-order-distortion-characteristic-calibration circuit; a quadrature-receive-signal-calibration circuit; and a test-signal generator. The test-signal generator generates first and second test signals using the transmit VCO. In the second-order-distortion-characteristic-calibration mode, the second-order-distortion-characteristic-calibration circuit variably changes an operation parameter of the receive mixer thereby to calibrate the second-order distortion characteristic to achieve its best condition while the first test signal is supplied to the receive mixer.
    Type: Grant
    Filed: November 29, 2010
    Date of Patent: April 2, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Koji Maeda, Taizo Yamawaki, Yukinori Akamine
  • Patent number: 8396430
    Abstract: Disclosed are a semiconductor integrated circuit device and a wireless communication system that are capable of improving reception sensitivity. The wireless communication system includes, for instance, a first duplexer, a second duplexer, a first low-noise amplifier circuit, and a second low-noise amplifier circuit. A transmission band compliant with a communication standard is split into two segments for use, namely, low- and high-frequency transmission bands. A reception band compliant with the communication standard is split into two segments for use, namely, low- and high-frequency reception bands. The first duplexer uses the low-frequency transmission band and low-frequency reception band as passbands. The second duplexer uses the high-frequency transmission band and high-frequency reception band as passbands.
    Type: Grant
    Filed: May 24, 2011
    Date of Patent: March 12, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Taizo Yamawaki, Tomonori Tanoue, Kazuaki Hori
  • Publication number: 20130049999
    Abstract: A reference A/D conversion unit is connected in parallel to an input common to a time-interleaved A/D converter to be a calibration target, and the output of each unitary A/D conversion unit which makes up the time-interleaved A/D converter is calibrated in a digital region by using a low-speed high-resolution A/D conversion result output from the reference A/D conversion unit. Also, fCLK/N (fCLK represents an overall sampling rate of the time-interleaved A/D converter, and N is relatively prime to the number of unitary A/D conversion units connected in parallel M) is set as the operation clock frequency of the reference A/D conversion unit. Samplings of all unitary A/D conversion units can be sequentially synchronized with the sampling of the reference A/D conversion unit, and the operation clock frequency of the reference A/D converter can be made N times slower than the overall sampling rate of the time-interleaved A/D converter.
    Type: Application
    Filed: December 28, 2011
    Publication date: February 28, 2013
    Inventors: TAKASHI OSHIMA, Taizo Yamawaki, Tomomi Takahashi
  • Patent number: 8359067
    Abstract: There is provided a radio frequency circuit device for multi-band and multi-mode which is low in a circuit loss, and a mobile communication terminal using the radio frequency circuit device. The radio frequency circuit device has a first path 110 that includes an amplifier 10a that amplifies signals of at least two modulation techniques in power, a matching network 20 that is connected to the amplifier and a duplexer 50 and allows the matching network to be coupled with an antenna, and a second path 111 that does not include the duplexer and allows the matching network to be coupled with the antenna. The first path is selected when the amplifier amplifies one of the signals of at least two modulation techniques, and the second path is selected when the amplifier amplifies another signal. An output impedance of the amplifier is matched with an impedance when viewing the antenna side from the amplifier in the first path and the second path.
    Type: Grant
    Filed: August 3, 2011
    Date of Patent: January 22, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Akira Kuriyama, Taizo Yamawaki, Satoshi Tanaka
  • Patent number: 8346180
    Abstract: A transceiver includes an oscillator and a plurality of communication blocks. Each of the communication blocks includes frequency dividers and mixers. Frequency dividing number of the frequency divider included in one communication block is set to an even-numbered integer, and transmission local signals supplied from the frequency dividers to the mixer become quadrature signals having a phase difference of 90 degrees. The frequency dividing number of another frequency divider in the another communication block is set to a non-integer, and communication local signals supplied from the frequency divider to the mixers become non-quadrature signals having a phase difference at a predetermined offset angle from 90 degrees. The transceiver further includes a converting unit for giving a compensation offset amount having almost the same absolute value and having a polarity opposite to that of the offset angle to communication analog signals related to the mixer of the another communication block.
    Type: Grant
    Filed: September 21, 2011
    Date of Patent: January 1, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Hiroshi Kamizuma, Satoshi Tanaka, Taizo Yamawaki, Yukinori Akamine, Koji Maeda
  • Publication number: 20120320957
    Abstract: The transmitter of the transceiver includes: a transmitter-side mixers of a transmitter-side modulator; a transmitter-side voltage-controlled oscillator; and a transmitter-side divider. The divider having a dividing factor of a non-integral number is supplied with an oscillating output of the oscillator. A pair of non-quadrature local signals having a phase difference of 90° plus a predetermined offset angle is produced by the divider and supplied to the mixers. The transmitter includes a phase-shift unit which converts a pair of quadrature transmit signals having a phase difference of about 90° on an analog basis into a pair of non-quadrature shifted transmit signals. Consequently, quadrature modulation is performed by the mixers. Use of a similar configuration enables the reduction in interference of an RF signal with local signals supplied to receiver-side mixers of the receiver.
    Type: Application
    Filed: August 23, 2012
    Publication date: December 20, 2012
    Inventors: Satoshi TANAKA, Hiroshi Kamizuma, Koji Maeda, Sungwoo Cha, Yukinori Akamine, Taizo Yamawaki