Patents Examined by Marc Hoff
  • Patent number: 5144307
    Abstract: The present invention can provide an integral A-D converter of high frequency and of high accuracy and capable of reducing the influence of the integrating capacitor caused by the electric charge absorption property thereof because it compensates the measured data by substracting the compensating data from the measured data, the compensating data being the repeatedly A-D converted data of the ground voltage during the standardized initiating time of the integrating capacitor.
    Type: Grant
    Filed: June 28, 1991
    Date of Patent: September 1, 1992
    Assignee: Ando Electric Co., Ltd.
    Inventor: Tomohide Takatsuka
  • Patent number: 5140324
    Abstract: A superconducting sigma-delta analog-to-digital converter utilizes a superconducting inductor as the integrator and a Josephson junction connected in series between the inductor and ground as the quantizer. A SQUID generates sampling pulses at a selected GHz frequency which add to the inductor current flowing through the Josephson junction. When the combined current through the Josephson junction exceeds the critical current of the Josephson junction, a voltage pulse is generated which kicks back into the inductor to reduce the inductor current. The voltage across the Josephson junction is, therefore, a one bit digital representation of the analog signal. This one bit digital signal is converted to a multi-bit digital signal preferably by a decimator having superconducting circuits which reduce the frequency of the multi-bit digital signal to a frequency which can be further processed by semiconductor processors. Preferably, a weighting function is utilized in a conversion to improve accuracy.
    Type: Grant
    Filed: June 6, 1991
    Date of Patent: August 18, 1992
    Assignee: Westinghouse Electric Corp.
    Inventors: John X. Przybysz, Donald L. Miller, Eric H. Naviasky
  • Patent number: 5136293
    Abstract: This invention is a D/A converter including a preset current source, first and second differential switches for selectively deriving an output current of the preset current source in response to complementary signals supplied to control electrodes thereof, and an imaginary short circuit for connecting output portions of current paths of the switches to each other. Variation in the voltage at the time of switching operation of the differential switch can be suppressed by use of the imaginary short circuit with the above construction, thus making it possible to enhance the operation speed.
    Type: Grant
    Filed: June 4, 1991
    Date of Patent: August 4, 1992
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenji Matsuo, Yasukazu Noine, Kazuhiko Kasai
  • Patent number: 5117227
    Abstract: A continuously integrating analog-to-digital converter (ADC) calculates a digital output by integrating an input voltage over a number of time intervals using a multisloping technique to define the input voltage in terms of a slope count. A residue ADC is used in lieu of a run-down interval of the integrator to calculate the least significant bits of the ADC digital output. This is accomplished by first sampling the integrator output voltage, and then after a number of time intervals, sampling the integrator output voltage a second tune. The difference between the two residue voltages is converted into a fractional slope count by multiplication with a calibration constant. The fractional slope count can then be added to the slope count from the integrator, so that the resulting total slope count is directly proportional to the input voltage at a high resolution.
    Type: Grant
    Filed: September 27, 1991
    Date of Patent: May 26, 1992
    Assignee: Hewlett-Packard Company
    Inventor: Wayne C. Goeke