Patents Examined by Aristoelis M. Psitos
  • Level shift circuit of optical disc apparatus
    Patent number: 5005163
    Abstract: A circuit for shifting the level of a signal inputted in the focussing or tracking servocircuit provided with an automatic gain control device in an optical disc apparatus. The circuit comprises a plurality of variable gain amplifiers arranged at a stage prior to detecting a focussing or tracking error and forming the corresponding error signal, inclusive of gain set apparatus for selecting one of a plurality of gains of said gain amplifiers depending on the detected level range of the light quantity reflected from the optical disc.
    Type: Grant
    Filed: May 16, 1990
    Date of Patent: April 2, 1991
    Assignee: Nakamichi Corp.
    Inventors: Makoto Yamamoto, Akio Terada