Patents by Inventor David T. L. Chang

David T. L. Chang 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: 4323930
    Abstract: A U-Matic video tape recorder of the type which is modified so as to employ wide-band-direct circuitry for developing a modulated signal from a video signal and to divide each frame of the modulated signal into several segments for recordation upon respective tracks of a tape is further modified to include circuitry for transporting the tape at a reduced rate wherein each segment of the modulated signal is multiply reproduced and circuitry for combining one of each multiply reproduced segments of a signal developed by a demodulator of the reproduced modulated signal with a black-level video signal to develop a signal representing in slow motion the original video signal.
    Type: Grant
    Filed: October 6, 1980
    Date of Patent: April 6, 1982
    Assignee: Recortec, Inc.
    Inventor: David T. L. Chang
  • Patent number: 4214259
    Abstract: An EIAJ-2, video tape recorder and reproducer machine having broadcast quality response characteristics achieved through the use of a wide band direct type FM modulator for encoding a video signal for recording onto a video tape, a pair of record/playback heads carried by a rotating drum which is partially wrapped by a length of the video tape which is transported past the drum such that the heads scan the tape in helical fashion, the speed of the drum being such that each head records upon a respective track of the video tape a segment of the modulated video signal which correspond to 1/3 of a field of the video signal, an FM demodulator for decoding the frequency modulated video signal which is recovered during playback, circuits for synchronizing the speed of the drum with the synchronization pulses of the video signal and for controlling the speed with which the tape is transported pass the drum and circuitry for minimizing distortion of the video signal caused when the segmented portions of the video sig
    Type: Grant
    Filed: April 7, 1978
    Date of Patent: July 22, 1980
    Assignee: Recortec, Inc.
    Inventor: David T. L. Chang
  • Patent number: 4104685
    Abstract: A video recorder/reproducer tape transport including a supply reel, a take-up reel, a helical scanner head assembly for recording and reproducing signals on the tape in a helical scan format, a capstan, a first movable tension tape guide positioned within the tape path intermediate the scanner head assembly and one of said reels and being movable under tension between a first location and a second location, the first movable tension tape guide being constantly under tension urging it towards the first location in opposition to the tension on the tape, and a second movable tension tape guide positioned within the tape path intermediate the other of the reels and the capstan, and being movable under tension between a third and a fourth location, the second movable tension tape guide being constantly under tension urging it toward the third location in opposition to the tension on the tape.
    Type: Grant
    Filed: January 13, 1977
    Date of Patent: August 1, 1978
    Assignee: Recortec, Inc.
    Inventor: David T. L. Chang