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Disk apparatus and method of generating a tracking error signal

  • US 7,295,498 B2
  • Filed: 12/02/2003
  • Issued: 11/13/2007
  • Est. Priority Date: 12/03/2002
  • Status: Expired due to Fees
First Claim
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1. A disk apparatus which reproduces information by irradiating an optical beam to a disk, the disk apparatus comprising:

  • a photodetector which comprises two or more photodetection cells, receives a reflected light from a disk, and outputs a photodetection signal based on the received reflected light;

    a first tracking error signal generator which detects a phase difference between the photodetection signals from the photodetector, and generates a first tracking error signal corresponding to the phase difference;

    a first variable amplifier which varies an amplitude of the first tracking error signal;

    a second tracking error signal generator which detects a level difference between the photodetection signals from the photodetector; and

    generates from the photodetection signal a second tracking error signal corresponding to the level difference;

    a second variable amplifier which varies an amplitude of the second tracking error signal;

    an adder which adds the first and second tracking error signals generated by the first and second variable amplifiers to provide an added tracking error signal;

    a muting unit which mutes the first tracking error signal when the first tracking error signal amplitude is lower than a predetermined reference, and mutes the second tracking error signal when the second tracking error signal amplitude is lower than a predetermined reference; and

    a tracking control unit which controls tracking by using the added error signal provided from the adder.

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