Patents by Inventor Koji Asami

Koji Asami 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: 7292166
    Abstract: There is provided an analog-to-digital conversion apparatus that corrects digital data output from a plurality of analog-to-digital conversion units.
    Type: Grant
    Filed: May 26, 2005
    Date of Patent: November 6, 2007
    Assignee: Advantest Corporation
    Inventor: Koji Asami
  • Publication number: 20070236227
    Abstract: An waveform converting apparatus is provided. The waveform converting apparatus includes: an amplitude converting section that multiplies an amplitude component of the input signal more than a predetermined amplitude value by a conversion coefficient which gradually decreases in accordance with the amplitude value; and a filter that removes a frequency component out of the frequency band of the input signal among the frequency components of the signal generated by the amplitude converting section.
    Type: Application
    Filed: April 16, 2007
    Publication date: October 11, 2007
    Applicant: ADVANTEST CORPORATION
    Inventor: Koji Asami
  • Patent number: 7197413
    Abstract: There is provided a delay amount measuring method of measuring a delay amount in an electronic device that outputs an output signal according to an input signal. The method includes a conversion step of converting the input signal and the output signal into digital data, a shift step of sequentially shifting the digital data of either of the input signal or the output signal in a time direction, an error computing step of computing a squared error of the digital data of the input signal and the digital data of the output signal with respect to each shift amount in the shift step, and a delay amount computing step of computing the shift amount when the squared error is a minimum value by means of a nonlinear least squares method and using the computed shift amount as the delay amount in the electronic device.
    Type: Grant
    Filed: October 14, 2005
    Date of Patent: March 27, 2007
    Assignee: Advantest Corporation
    Inventor: Koji Asami
  • Patent number: 7173443
    Abstract: A mixed signal test system for testing a semiconductor device having both an analog function and a digital function achieves improved resolution and low cost. The test system is formed of a functional test unit for testing a digital function of a device under test (DUT), an analog test unit (ATU) for testing an analog function of the DUT, and a synchronous control unit for synchronizing operations between the functional test unit and the analog test unit. The analog test unit includes a digitizer for converting an analog output of the DUT into a digital signal, and an acquisition memory for storing the digital signal from the digitizer in specified addresses. The wave form of the analog output is repeated by a plurality of cycles and a sampling clock for the digitizer is phase shifted by a predetermined amount for each cycle.
    Type: Grant
    Filed: November 18, 1999
    Date of Patent: February 6, 2007
    Assignee: Advantest Corp.
    Inventor: Koji Asami
  • Publication number: 20060267813
    Abstract: There is provided an analog-to-digital conversion apparatus that corrects digital data output from a plurality of analog-to-digital conversion units.
    Type: Application
    Filed: May 26, 2005
    Publication date: November 30, 2006
    Applicant: Advantest Corporation
    Inventor: Koji Asami
  • Publication number: 20060267814
    Abstract: There is provided an analog-to-digital conversion apparatus that corrects digital data output from a plurality of analog-to-digital conversion units.
    Type: Application
    Filed: February 21, 2006
    Publication date: November 30, 2006
    Applicant: Advantest Corporation
    Inventor: Koji Asami
  • Patent number: 7119724
    Abstract: There is provided an analog-to-digital conversion apparatus that converts analog signals into digital signals.
    Type: Grant
    Filed: May 25, 2005
    Date of Patent: October 10, 2006
    Assignee: Advantest Corporation
    Inventor: Koji Asami
  • Patent number: 7106236
    Abstract: An analog-to-digital converting method for converting an analog signal into a digital signal is provided, wherein the analog-to-digital converting method includes a measuring step of measuring a frequency characteristic of each of analog-to-digital converters in advance, a sampling step of sampling the analog signal, a Fourier transformation step of performing Fourier transformation on the data sampled by the plurality of analog-to-digital converters and generating a plurality of frequency domain signals, a correcting step of converting each of the frequency domain signals into a signal to be acquired in case that the frequency characteristic of corresponding analog-to-digital converter is ideal, by multiplying each of the frequency domain signals by a correction coefficient determined on the basis of the frequency characteristics of all the analog-to-digital converters, and a synthesizing step of synthesizing each of the frequency domain signals acquired at the correcting step and generating a frequency spec
    Type: Grant
    Filed: October 14, 2004
    Date of Patent: September 12, 2006
    Assignee: Advantest Corporation
    Inventors: Koji Asami, Kiyoshi Hashiba
  • Publication number: 20060161383
    Abstract: There is provided a delay amount measuring method of measuring a delay amount in an electronic device that outputs an output signal according to an input signal. The method includes a conversion step of converting the input signal and the output signal into digital data, a shift step of sequentially shifting the digital data of either of the input signal or the output signal in a time direction, an error computing step of computing a squared error of the digital data of the input signal and the digital data of the output signal with respect to each shift amount in the shift step, and a delay amount computing step of computing the shift amount when the squared error is a minimum value by means of a nonlinear least squares method and using the computed shift amount as the delay amount in the electronic device.
    Type: Application
    Filed: October 25, 2005
    Publication date: July 20, 2006
    Applicant: Advantest Corporation
    Inventor: Koji Asami
  • Publication number: 20050270213
    Abstract: An analog-to-digital converting method for converting an analog signal into a digital signal is provided, wherein the analog-to-digital converting method includes a measuring step of measuring a frequency characteristic of each of analog-to-digital converters in advance, a sampling step of sampling the analog signal, a Fourier transformation step of performing Fourier transformation on the data sampled by the plurality of analog-to-digital converters and generating a plurality of frequency domain signals, a correcting step of converting each of the frequency domain signals into a signal to be acquired in case that the frequency characteristic of corresponding analog-to-digital converter is ideal, by multiplying each of the frequency domain signals by a correction coefficient determined on the basis of the frequency characteristics of all the analog-to-digital converters, and a synthesizing step of synthesizing each of the frequency domain signals acquired at the correcting step and generating a frequency spec
    Type: Application
    Filed: October 14, 2004
    Publication date: December 8, 2005
    Applicant: Advantest Corporation
    Inventors: Koji Asami, Kiyoshi Hashiba
  • Publication number: 20050141642
    Abstract: A detector for detecting a signal to be measured, which is made to discrete with a predetermined discrete frequency, is provided, wherein the detector includes an analysis signal transformer for eliminating aliasing components of the signal to be measured, which are generated due to the discreteness, by transforming the signal to be measured into an analysis signal of which the discrete frequency is lower than that of the signal to be measured, and a base band signal generating unit for frequency-shifting the analysis signal and generating a complex base band signal of the signal to be measured.
    Type: Application
    Filed: December 27, 2004
    Publication date: June 30, 2005
    Applicant: Advantest Corporation
    Inventor: Koji Asami
  • Patent number: 6867719
    Abstract: A digitizer module comprises an AD converter for sampling a pair of analog signals at a predetermined time interval and converting into a first and second digital signals respectively, a second signal frequency component calculating unit for calculating a second signal frequency component representing a component of each frequency of the second digital signal on the basis of the second digital signal, a skew frequency component calculating unit for calculating a skew frequency component representing a phase error of each frequency of the second digital signal corresponding to the first digital signal on the basis of a skew of a timing with which the pair of analog signals are sampled by the AD converter and a second signal frequency component correcting unit for correcting the second signal frequency component on the basis of the skew frequency component.
    Type: Grant
    Filed: August 25, 2004
    Date of Patent: March 15, 2005
    Assignee: Advantest Corporation
    Inventor: Koji Asami
  • Publication number: 20050024244
    Abstract: A digitizer module comprises an AD converter for sampling a pair of analog signals at a predetermined time interval and converting into a first and second digital signals respectively, a second signal frequency component calculating unit for calculating a second signal frequency component representing a component of each frequency of the second digital signal on the basis of the second digital signal, a skew frequency component calculating unit for calculating a skew frequency component representing a phase error of each frequency of the second digital signal corresponding to the first digital signal on the basis of a skew of a timing with which the pair of analog signals are sampled by the AD converter and a second signal frequency component correcting unit for correcting the second signal frequency component on the basis of the skew frequency component.
    Type: Application
    Filed: August 25, 2004
    Publication date: February 3, 2005
    Inventor: Koji Asami
  • Publication number: 20050017885
    Abstract: A digitizer module comprises an AD converter for sampling a pair of analog signals at a predetermined time interval and converting into a first and second digital signals respectively, a second signal frequency component calculating unit for calculating a second signal frequency component representing a component of each frequency of the second digital signal on the basis of the second digital signal, a skew frequency component calculating unit for calculating a skew frequency component representing a phase error of each frequency of the second digital signal corresponding to the first digital signal on the basis of a skew of a timing with which the pair of analog signals are sampled by the AD converter and a second signal frequency component correcting unit for correcting the second signal frequency component on the basis of the skew frequency component.
    Type: Application
    Filed: August 25, 2004
    Publication date: January 27, 2005
    Inventor: Koji Asami
  • Publication number: 20050017886
    Abstract: A digitizer module comprises an AD converter for sampling a pair of analog signals at a predetermined time interval and converting into a first and second digital signals respectively, a second signal frequency component calculating unit for calculating a second signal frequency component representing a component of each frequency of the second digital signal on the basis of the second digital signal, a skew frequency component calculating unit for calculating a skew frequency component representing a phase error of each frequency of the second digital signal corresponding to the first digital signal on the basis of a skew of a timing with which the pair of analog signals are sampled by the AD converter and a second signal frequency component correcting unit for correcting the second signal frequency component on the basis of the skew frequency component.
    Type: Application
    Filed: August 25, 2004
    Publication date: January 27, 2005
    Inventor: Koji Asami
  • Patent number: 6836235
    Abstract: A digitizer is provided which includes: N A/D converters for converting an analog signal output from an electronic device to digital signals at different sampling timings by turns (N is an integer equal to or larger than 2); and N digital filters for outputting corrected signals obtained by multiplying the digital signals output from the N A/D converters by correction coefficients, wherein the correction coefficients are based on phase errors between ideal sampling timings at which associated A/D converters are to sample the analog signal and actual sampling timings at which the N A/D converters sampled the analog signal, respectively.
    Type: Grant
    Filed: August 19, 2003
    Date of Patent: December 28, 2004
    Assignee: Advantest Corporation
    Inventor: Koji Asami
  • Patent number: 6836227
    Abstract: A digitizer module comprises an AD converter for sampling a pair of analog signals at a predetermined time interval and converting into a first and second digital signals respectively, a second signal frequency component calculating unit for calculating a second signal frequency component representing a component of each frequency of the second digital signal on the basis of the second digital signal, a skew frequency component calculating unit for calculating a skew frequency component representing a phase error of each frequency of the second digital signal corresponding to the first digital signal on the basis of a skew of a timing with which the pair of analog signals are sampled by the AD converter and a second signal frequency component correcting unit for correcting the second signal frequency component on the basis of the skew frequency component.
    Type: Grant
    Filed: February 25, 2003
    Date of Patent: December 28, 2004
    Assignee: Advantest Corporation
    Inventor: Koji Asami
  • Patent number: 6809668
    Abstract: An interleaving A/D conversion type waveform digitizer module comprising a means for eliminating spurious components resulting from phase errors according to N A/D converters, wherein the digitizer samples signals continually with a predetermined timing corresponding to a interleaving configuration of the A/D converters, receives signals outputted by a tested device to be tested, converts the signals into digital signals, performs Fourier-transform of the digital signals and performs interleaving.
    Type: Grant
    Filed: February 26, 2003
    Date of Patent: October 26, 2004
    Assignee: Advantest Corporation
    Inventor: Koji Asami
  • Patent number: 6801145
    Abstract: An interleaving A/D conversion type waveform digitizer module comprising a means for eliminating spurious components resulting from phase errors according to N A/D converters, wherein the digitizer samples signals continually with a predetermined timing corresponding to a interleaving configuration of the A/D converters, receives signals outputted by a tested device to be tested, converts the signals into digital signals, performs Fourier-transform of the digital signals and performs interleaving.
    Type: Grant
    Filed: February 13, 2003
    Date of Patent: October 5, 2004
    Assignee: Advantest Corporation
    Inventor: Koji Asami
  • Publication number: 20040164889
    Abstract: A digitizer module comprises an AD converter for sampling a pair of analog signals at a predetermined time interval and converting into a first and second digital signals respectively, a second signal frequency component calculating unit for calculating a second signal frequency component representing a component of each frequency of the second digital signal on the basis of the second digital signal, a skew frequency component calculating unit for calculating a skew frequency component representing a phase error of each frequency of the second digital signal corresponding to the first digital signal on the basis of a skew of a timing with which the pair of analog signals are sampled by the AD converter and a second signal frequency component correcting unit for correcting the second signal frequency component on the basis of the skew frequency component.
    Type: Application
    Filed: February 25, 2003
    Publication date: August 26, 2004
    Inventor: Koji Asami