Patents by Inventor Isao Ikuta
Isao Ikuta 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: 7805123Abstract: A technique of frequency hopping communication capable of high-speed switching of a plurality of signals having ultra-wide band 528 MHz bandwidth at high-speed and setting and switching a band center frequency and the number of bands arbitrary is provided. A radio transceiver has a frequency hopping communication function of UWB system for switching the ultra wide band signal. In the device, high-speed frequency hopping is realized by controlling an SSB mixer in a local oscillator circuit and switching the frequency of a DDS. The device sets NCO data to the DDS and switches a quadrature phase signal of an output, and switches a signal input of an input terminal of the SSB mixer by a control of a phase switching switch. One of a sum component and a difference component of a mixture of first and second quadrature phase signals is outputted from the output terminal of the SSB mixer.Type: GrantFiled: April 20, 2007Date of Patent: September 28, 2010Assignee: Renesas Technology Corp.Inventors: Yoshikazu Sugiyama, Isao Ikuta, Yusaku Katsube
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Patent number: 7418250Abstract: Because there are different voltages at two current output terminals of a current divider, the voltages at the current input terminals of two current switch circuits are not affected mutually even with a large amplitude of local signals. Accordingly, the performance of a quadrature mixer can be enhanced by increasing the amplitude of the local signals. Bias currents are supplied to the two current switch circuits through the current divider from a common DC current source which essentially supplies a bias current to a V/I converter and, therefore, power consumption is reduced.Type: GrantFiled: February 9, 2007Date of Patent: August 26, 2008Assignee: Renesas Technology Corp.Inventors: Yutaka Igarashi, Isao Ikuta, Akio Yamamoto
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Patent number: 7340232Abstract: The invention provides a receiving system and a transmitting system capable of decreasing an offset between differential signals and between quadrature signals and improving a manufacturing yield and a semiconductor integrated circuit device for processing a wireless communication signal having therein the systems. A receiving system includes: a local oscillator for generating an oscillation signal in a desired frequency; a 90-degree phase-shifting circuit for generating a signal by shifting a phase of the oscillation signal output from the local oscillator by 90 degrees; a first mixer for mixing one of differential reception signals with an output signal of the first 90-degree phase-shifting circuit and outputting frequency-converted differential signals; and a second mixer for mixing another one of the differential reception signals with an output signal of the local oscillator and outputting frequency-converted differential signals.Type: GrantFiled: May 11, 2004Date of Patent: March 4, 2008Assignee: Renesas Technology Corp.Inventors: Motoki Murakami, Yutaka Igarashi, Akio Yamamoto, Isao Ikuta, Yoshiaki Harasawa
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Publication number: 20070189361Abstract: A technique of frequency hopping communication capable of high-speed switching of a plurality of signals having ultra-wide band 528 MHz bandwidth at high-speed and setting and switching a band center frequency and the number of bands arbitrary is provided. A radio transceiver has a frequency hopping communication function of UWB system for switching the ultra wide band signal. In the device, high-speed frequency hopping is realized by controlling an SSB mixer in a local oscillator circuit and switching the frequency of a DDS. The device sets NCO data to the DDS and switches a quadrature phase signal of an output, and switches a signal input of an input terminal of the SSB mixer by a control of a phase switching switch. One of a sum component and a difference component of a mixture of first and second quadrature phase signals is outputted from the output terminal of the SSB mixer.Type: ApplicationFiled: April 20, 2007Publication date: August 16, 2007Inventors: YOSHIKAZU SUGIYAMA, Isao Ikuta, Yusaku Katsube
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Publication number: 20070135074Abstract: Because there are different voltages at two current output terminals of a current divider, the voltages at the current input terminals of two current switch circuits are not affected mutually even with a large amplitude of local signals. Accordingly, the performance of a quadrature mixer can be enhanced by increasing the amplitude of the local signals. Bias currents are supplied to the two current switch circuits through the current divider from a common DC current source which essentially supplies a bias current to a V/I converter and, therefore, power consumption is reduced.Type: ApplicationFiled: February 9, 2007Publication date: June 14, 2007Applicant: Renesas Technology CorporationInventors: Yutaka Igarashi, Isao Ikuta, Akio Yamamoto
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Patent number: 7184739Abstract: Because there are different voltages at two current output terminals of a current divider, the voltages at the current input terminals of two current switch circuits are not affected mutually even with a large amplitude of local signals. Accordingly, the performance of a quadrature mixer can be enhanced by increasing the amplitude of the local signals. Bias currents are supplied to the two current switch circuits through the current divider from a common DC current source which essentially supplies a bias current to a V/I converter and, therefore, power consumption is reduced.Type: GrantFiled: November 13, 2003Date of Patent: February 27, 2007Assignee: Renesas Technology Corp.Inventors: Yutaka Igarashi, Isao Ikuta, Akio Yamamoto
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Publication number: 20060220757Abstract: A radio frequency IC includes a PLL circuit and prevents a PLL loop from being easily unlocked upon fluctuation of VCO oscillation frequencies due to a change in temperature. The PLL loop includes a VCO capable of switching oscillation frequency bands, a variable frequency divider, a phase comparison circuit, and a loop filter. A switching switch can apply one of plural predetermined set voltages to the VCO in place of a voltage of the loop filter in an open state in which the loop filter is disconnected from the VCO. The radio frequency IC als has a decision circuit that decides whether the phase of output of the variable frequency divider is ahead of or lags behind that of a reference signal of a predetermined frequency, and an automatic band switching circuit that generates a signal for switching VCO frequency bands, based on output of the decision circuit.Type: ApplicationFiled: March 28, 2006Publication date: October 5, 2006Inventors: Kunito Satake, Hirotaka Oosawa, Isao Ikuta, Satoru Yamamoto
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Publication number: 20060181362Abstract: There are provided a voltage-controlled oscillator and an RF-IC for W-CDMA, which are capable of ensuring a wide frequency range and improving oscillation stability. The voltage-controlled oscillator (RF-IC) includes: switching A and B inductors generating a magnetic interaction between resonant A and B inductors of a resonant circuit; and an A_NMOS, a B_NMOS, a C_NMOS, and D_NMOS as switch/load means having together a function of changing an inductance value by the magnetic interaction between the resonant A and B inductors and the switching A and B inductors and a function of serving as loads of the switching A and B inductors. The A_NMOS, the B_NMOS, the C_NMOS, and the D_NMOS are turned ON/OFF by a control signal so as to control the mutual induction, whereby the oscillation frequency is switched by changing the inductance value of the resonant circuit. Also, oscillation stability is improved by increasing the inductance value.Type: ApplicationFiled: November 17, 2005Publication date: August 17, 2006Inventors: Isao Ikuta, Akio Yamamoto, Yusaku Katsube, Toshiya Uozumi, Yasuyuki Kimura
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Publication number: 20060128334Abstract: To reduce circuit area and power consumption and suppress transient response occurring at switching in PGA of a programmable gain amplifier is provided a wireless communication receiver comprising PGAs for adjusting the gain of a received signal down-converted by mixers and sending it to base-band block. Within PGAs are provided HPFATT circuits formed of capacitors arranged in series, and ladder resistors arranged in parallel, with signal lines, and a plurality of switches. HPFATT is a circuit serving as a high-pass filter and an attenuator for gain switching, wherein switches are controlled by control signal sg from a controller. Amplifiers connected to the rear stage of the HPFATT circuit are formed of MOS transistors.Type: ApplicationFiled: June 30, 2005Publication date: June 15, 2006Inventors: Isao Ikuta, Akio Yamamoto, Yutaka Igarashi, Stephen Goodwin
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Publication number: 20050147192Abstract: A high frequency signal receiver comprising a variable gain amplifier, a first filter for restricting a bandwidth of an analog baseband signal, an AD converter connected to the first filter, a second filter for restricting the bandwidth of an output of the AD converter, an interference wave detection circuit for detecting the level of an interference wave in the received signal, and a controller for controlling the first filter to have a wide bandwidth when the level of the interference wave is lower than a threshold level, and switching the first filter to have a narrow bandwidth while changing the characteristics of the second filter so as to compensate deterioration of the pass-band of the first filter when the level of the interference wave is equal to or greater than the threshold level.Type: ApplicationFiled: November 12, 2004Publication date: July 7, 2005Inventors: Akio Yamamoto, Yutaka Igarashi, Isao Ikuta
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Publication number: 20050118976Abstract: The invention provides a receiving system and a transmitting system capable of decreasing an offset between differential signals and between quadrature signals and improving a manufacturing yield and a semiconductor integrated circuit device for processing a wireless communication signal having therein the systems. A receiving system includes: a local oscillator for generating an oscillation signal in a desired frequency; a 90-degree phase-shifting circuit for generating a signal by shifting a phase of the oscillation signal output from the local oscillator by 90 degrees; a first mixer for mixing one of differential reception signals with an output signal of the first 90-degree phase-shifting circuit and outputting frequency-converted differential signals; and a second mixer for mixing another one of the differential reception signals with an output signal of the local oscillator and outputting frequency-converted differential signals.Type: ApplicationFiled: May 11, 2004Publication date: June 2, 2005Inventors: Motoki Murakami, Yutaka Igarashi, Akio Yamamoto, Isao Ikuta, Yoshiaki Harasawa
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Publication number: 20040147240Abstract: Because there are different voltages at two current output terminals of a current divider, the voltages at the current input terminals of two current switch circuits are not affected mutually even with a large amplitude of local signals. Accordingly, the performance of a quadrature mixer can be enhanced by increasing the amplitude of the local signals. Bias currents are supplied to the two current switch circuits through the current divider from a common DC current source which essentially supplies a bias current to a V/I converter and, therefore, power consumption is reduced.Type: ApplicationFiled: November 13, 2003Publication date: July 29, 2004Inventors: Yutaka Igarashi, Isao Ikuta, Akio Yamamoto
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Publication number: 20040105450Abstract: An image captured by a camera can be sent to and stored in a controller on a LAN as well as to a high-capacity camera with more memory than other camera devices on the LAN and to a camera on another LAN. This allows captured images to be recorded without losing the images even if an irregular event is detected and an irregularity takes place in the camera device at the site.Type: ApplicationFiled: May 20, 2003Publication date: June 3, 2004Applicant: Hitachi, Ltd.Inventors: Isao Ikuta, Tetsuo Nakano, Shinya Imanishi, Yutaka Igarashi
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Publication number: 20040048589Abstract: A radio communication apparatus for executing reliable communications is provided by detecting reception statuses of communication systems, and selecting one from the systems according to the detected reception statuses and power consumption.Type: ApplicationFiled: May 16, 2003Publication date: March 11, 2004Applicant: Hitachi, Ltd.Inventors: Akio Yamamoto, Katsuei Ichikawa, Isao Ikuta
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Publication number: 20040014450Abstract: A signal receiving apparatus comprises an analog control AGC having a continuously varying gain and a step control AGC having a gain switched in steps, one of which is used to control the gain of a baseband signal, and the other of which is used to control the gain of the gain controlled signal.Type: ApplicationFiled: July 14, 2003Publication date: January 22, 2004Inventors: Akio Yamamoto, Yutaka Igarashi, Isao Ikuta
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Patent number: 6628361Abstract: A wiring structure is provided, the wiring structure being formed by forming a laminated film of silver (Ag) or an alloy containing silver (Ag) as the major constituent and the other metallic material, and by forming a wiring pattern through a single process of photolithography.Type: GrantFiled: February 23, 2001Date of Patent: September 30, 2003Assignee: Hitachi, Ltd.Inventors: Takuya Takahashi, Yoichi Sakaki, Isao Ikuta, Katsumi Tamura, Ken-ichi Onisawa
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Publication number: 20030112382Abstract: A liquid crystal display device in which at least one of the scanning line GL, data line DL, source and drain electrodes SD1, SD2 of the thin film transistor TFT comprises a laminated film containing a first electroconductive film and a second electroconductive film, the first electroconductive film being made of a molybdenum-based Mo alloy and the second electroconductive film being made of a silver-based Ag alloy and disposed on the first electroconductive film, can be produced at low cost.Type: ApplicationFiled: September 20, 2001Publication date: June 19, 2003Inventors: Takuya Takahashi, Isao Ikuta, Katsumi Tamura, Youichi Sakaki, Ken-Ichi Onisawa, Masahiko Ando
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Publication number: 20010022635Abstract: A wiring structure is provided, the wiring structure being formed by forming a laminated film of silver (Ag) or an alloy containing silver (Ag) as the major constituent and the other metallic material, and by forming a wiring pattern through a single process of photolithography.Type: ApplicationFiled: February 23, 2001Publication date: September 20, 2001Inventors: Takuya Takahashi, Yoichi Sakaki, Isao Ikuta, Katsumi Tamura, Ken-ichi Onisawa
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Patent number: 6127210Abstract: A simple and convenient method of manufacturing a CMOS TFT semiconductor circuit device wherein a doping layer doped into a first conductivity type without a mask is compensated with a dopant of a second conductivity type having a high density so that the conductivity type of the doping layer of first conductivity type is inverted into the second conductivity type, and further, in order to carry out the inversion of the conductivity type by the compensation easily and reliably, the surface density of the dopant of the doping layer of first conductivity type is reduced prior to compensating with the dopant of second conductivity type.Type: GrantFiled: October 3, 1996Date of Patent: October 3, 2000Assignee: Hitachi, Ltd.Inventors: Akio Mimura, Hiroshi Suga, Masaichi Nagai, Youmei Shinagawa, Isao Ikuta
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Patent number: RE36624Abstract: The present invention provides an optical recording medium using an amorphous-crystalline phase-change for recording and erasing, wherein reflectivity of an optical recording medium-constituting recording film in an amorphous state is larger than that of the optical recording medium-constituting recording film in a crystalline state, or wherein absorptivity of an optical recording medium-constituting recording film in an amorphous state is smaller than that of the optical recording medium-constituting recording film in a crystalline state.Type: GrantFiled: January 15, 1998Date of Patent: March 21, 2000Assignee: Hitachi, Ltd.Inventors: Yoshihito Maeda, Isao Ikuta, Hisashi Andoh, Masaichi Nagai, Yoshimi Katoh, Yoshio Sato, Nobuyoshi Tsuboi, Hiroyuki Minemura