Patents by Inventor Hun C. Cho

Hun C. Cho 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: 4924483
    Abstract: A track counting circuit for an optical disk driver is disclosed. The pickup passing a track is detected through a differential amplifier receiving signals from photo diodes, an amplifier, a tracking processor, a positive zero crossing detector, and a negative zero crossing detector. The signals sensed by photo diodes are applied to one of the input terminals of each of a pair of NAND gates through a differential amplifier, level comparators and a flip-flop, and the other input terminals of the NAND gates receive the signals which are obtained by the signals sensed by the photo diodes being processed through an adder and a level comparator to distinguish whether the pickup is placed on the track or land of the disk, the output signals of the NAND gates controlling the output signals of a flip-flop which control an up/down counter to make an up/down count depending on the moving direction of the pickup on the track so that the intended track is found precisely and easily.
    Type: Grant
    Filed: September 16, 1988
    Date of Patent: May 8, 1990
    Assignee: Samsung Electronics Co. Ltd.
    Inventor: Hun C. Cho