Synchronization (e.g., H-sync To Subcarrier) Patents (Class 348/194)
  • Patent number: 6008859
    Abstract: An image data processing apparatus is described that prevents the period of a horizontal timing signal from being shifted. The apparatus includes a separator, a phase-locked loop, a detector, a compensator and a timing signal generator. The detector delays a reference clock signal in a shorter period than the period of the reference clock signal, in a step-like manner, to produce a plurality of delayed timing signals having step-like phase differences. The detector further contrasts the plurality of delayed timing signals with a horizontal sync signal and the reference clock signal to measure the phase difference and the period of the horizontal sync signal. The compensator sets a ratio for combining consecutive luminance data in accordance with the phase difference and the period of the reference clock signal and combines consecutive luminance data in accordance with the ratio to generate compensated luminance data.
    Type: Grant
    Filed: July 30, 1997
    Date of Patent: December 28, 1999
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Hiroya Ito, Masashi Kiyose
  • Patent number: 5986697
    Abstract: A method and apparatus for raster calibration is described. Calibration circuitry operates in the context of a local video subsystem which receives at least one sync signal from a remote video (typically graphics) subsystem. The calibration circuitry calibrates a local raster of the local video subsystem to a remote raster of the remote video subsystem. The calibration circuitry includes measurement circuitry for measuring a first duration of a first phase of the sync signal, and for measuring a second duration of a second phase of the sync signal. Processing logic compares the first and second durations and determines that the phase having the shorter duration is an active phase, the active phase corresponding to the polarity of the sync signal. The processing logic also adds the first and second durations to provide an estimate of the scan line period of the remote raster.
    Type: Grant
    Filed: April 7, 1997
    Date of Patent: November 16, 1999
    Assignee: Intel Corporation
    Inventor: Benjamin M. Cahill, III
  • Patent number: 5982952
    Abstract: A character reader comprises an input unit for reading characters by a scanner-typed photoelectric transfer unit as an image, creating the image data formed by binary pixel of white and black lying on the plain surface and entering the same, a tangent detecting unit for detecting tangent information on tangents contacting with black pixels forming a character string within the image data, a tilt deciding unit for deciding a representative tangent which is representative for the direction of a row of character string, from the above-mentioned tangents, on the basis of the tangent information detected by the tangent detecting unit.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: November 9, 1999
    Assignee: NEC Corporation
    Inventor: Yutaka Nakashima
  • Patent number: 5959682
    Abstract: A circuit for detecting a data segment sync signal of data segment consisting of a plurality of symbols in a high-definition television, includes a correlator for detecting a correlation value from a received data segment signal, a segment integrator for accumulating the detected correlation value by segments and attenuating the accumulated correlation value in response to an overflow prevention signal, a maximum-value detector for detecting a maximum accumulated correlation value in the segment from the segment integrator output, an overflow prevention circuit for generating the overflow prevention signal by comparing the detected maximum accumulated correlation value with a predetermined reference value, a sync position detector for detecting a symbol position having the detected maximum accumulated correlation value, and a synchronization signal generator for generating a synchronization signal at the symbol position corresponding to the detected maximum accumulated correlation value.
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: September 28, 1999
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ki-bum Kim, Hyun-soo Shin
  • Patent number: 5896180
    Abstract: A phase-locked loop circuit generates a clock signal synchronized with a color burst signal contained in a composite color picture signal. The phase-locked loop circuit contains a phase synchronization loop having a loop gain, extracts the color burst signal from the composite color picture signal, compares the phases of the generated clock signal and the color burst signal, and controls the phase of the generated clock signal to reduce the difference between the above phases. The phase-locked loop circuit further detects the vertical blanking signal, and reduces the loop gain for the duration of the vertical blanking signal. Alternatively, a horizontal synchronizing signal is used instead of the color burst signal. Another phase-locked loop circuit generates a clock signal synchronized with a reference clock signal based on first frequency information indicating a frequency of the reference clock signal.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: April 20, 1999
    Assignee: Fujitsu Limited
    Inventor: Toshiaki Usui
  • Patent number: 5710593
    Abstract: A digital test signal generator includes the ability to adjust the SCH phase of the output test signal. A color frame reset pulse is generated at the beginning of each color frame of the output test signal. The color frame reset pulse is input to a direct digital signal synthesizer together with an SCH phase adjust signal to initialize the synthesizer with an SCH phase offset at the beginning of each color frame. By varying the amount of the SCH phase offset, the SCH phase in the output test signal is varied.
    Type: Grant
    Filed: January 22, 1996
    Date of Patent: January 20, 1998
    Assignee: Tektronix, Inc.
    Inventor: John C. Reynolds
  • Patent number: 5668594
    Abstract: A method and apparatus for raster calibration is described. Calibration circuitry operates in the context of a local video subsystem which receives at least one sync signal from a remote video (typically graphics) subsystem. The calibration circuitry calibrates a local raster of the local video subsystem to a remote raster of the remote video subsystem. The calibration circuitry includes measurement circuitry for measuring a first duration of a first phase of the sync signal, and for measuring a second duration of a second phase of the sync signal. Processing logic compares the first and second durations and determines that the phase having the shorter duration is an active phase, the active phase corresponding to the polarity of the sync signal. The processing logic also adds the first and second durations to provide an estimate of the scan line period of the remote raster.
    Type: Grant
    Filed: January 3, 1995
    Date of Patent: September 16, 1997
    Assignee: Intel Corporation
    Inventor: Benjamin M. Cahill, III
  • Patent number: 5614944
    Abstract: In a video signal test, a sync signal test is first performed in which specification items of sync signals are measured. If the result is good, then a dot level test is performed using a dot discriminating pattern in which a dot level of the video signal changes between the maximum value and the minimum value for every dot. If the result is good, then a gradation test is finally performed using a gradation change pattern in which the gradation gradually changes for every horizontal line. In a case that the gradation test result is determined to be good, the functions of the video signal generator are finally judged to be good. On the other hand, if any one of the testing results is not good, the function test is ended at that stage without executing the next test.
    Type: Grant
    Filed: March 30, 1995
    Date of Patent: March 25, 1997
    Assignee: NEC Corporation
    Inventors: Toru Taura, Hirobumi Inoue
  • Patent number: 5510859
    Abstract: Disclosed is a tuned channel detector which includes a cable path between a radio frequency source and a receiver such as a TV, wherein the radio frequency source passes first through an attenuator and second through a signal selection module comprising two opposing directional couplers and a single-pole/double-throw switch. The channel to which the TV is tuned is determined by measuring the TV's local oscillator signal from the cable which feeds the radio frequency signal to the TV and, additionally or alternatively, by comparing the signal strength of the input and reflected TV carrier signals at and around the channels under test. Signal detection is further enhanced by modulating the signal mixed with the local oscillator with a tone and/or testing only during certain intervals such as the vertical synchronization interval or the power line cycle. A tone detector having a synchronous rectifier is used to detect low level local oscillator signals.
    Type: Grant
    Filed: December 7, 1994
    Date of Patent: April 23, 1996
    Assignee: Information Resources, Inc.
    Inventors: Ralph G. Douglass, Arthur R. Furman
  • Patent number: 5451999
    Abstract: The presence and stability of the input digital video signal of a digital video device, such as a digital video tape recorder system, is determined by a system control microprocessor running a program for periodically reading signals from an input data clock presence detector circuit, a circuit detecting presence of timing reference code words in the input digital video signal, and circuits measuring rates of single-bit and multiple-bit errors in the detected timing reference code words. The input signal is determined present and stable if the input data clock is present, timing reference code words are present, and if measured sync data error rates do not exceed some experimentally determined threshold values.
    Type: Grant
    Filed: November 5, 1992
    Date of Patent: September 19, 1995
    Assignee: Ampex Corporation
    Inventor: Jan S. Wesolowski
  • Patent number: 5410245
    Abstract: A method and apparatus of calibrating electronic scales for the horizontal axis of an oscilloscope is provided. For each of two electronic scales or cursors, output voltages of a horizontal deflection circuit are generated. A measurement is made to determine a time interval in which the voltage of a sweep waveform, generated by a sweep waveform generator and appearing at the output of the horizontal deflection circuit, passes the two output voltages. The slope of the sweep waveform generated by the sweep waveform generator is adjusted such that the time interval coincides with a target time interval.
    Type: Grant
    Filed: July 29, 1993
    Date of Patent: April 25, 1995
    Assignee: Leader Electronics Corp.
    Inventors: Kenzo Ikuzawa, Kentaro Ozawa, Susumu Mogi, Hirohisa Mita, Kouji Furihata
  • Patent number: RE36508
    Abstract: A method of automatically measuring the horizontal scan frequency of a composite synchronism signal, comprising horizontal synchronization impulses at line frequency, consists of first performing a count of a number of impulses having a repeat frequency higher than said line frequency, as intervening between two successive impulses at line frequency.The count value, corresponding to said number of impulses, is stored to obtain the line frequency of the signal, and thereafter, a series of down counts is effected, as initiated at predetermined times, until a change of frequency of the signal is detected.
    Type: Grant
    Filed: September 17, 1997
    Date of Patent: January 18, 2000
    Assignee: SGS-Thomson Microelectronics S.r.l.
    Inventors: Silvano Gornati, Giorgio Betti, Fabrizio Sacchi, Gianfranco Vai, Maurizio Zuffada