Method and system for a disc player tracking servo
Tracking system for optical record medium
Scanning beam control system
Focus servo control system for automatically adjusting a relative distance between an objective lens unit and a recording surface of an optical recording medium
Tracking servo signal generating device in an apparatus for reading recorded information Patent #: 4506149
ApplicationNo. 06/550540 filed on 11/10/1983
US Classes:369/44.25, Servo signal compared to a reference signal369/44.32, Means to compensate for defect or abnormal condition369/44.36, Variable gain369/44.37, Plural incident beams369/44.41, Arithmetic operation using plural photodetectors369/53.15Defect
ExaminersPrimary: Cardillo, Raymond F. Jr.
Assistant: Nguyen, Hiep T.
Attorney, Agent or Firm
International ClassG11B 7/09 (20060101)
Foreign Application Priority Data1982-11-11 JP
AbstractA tracking servocontrol circuit for use in an optical reproducing apparatus comprises a signal generator for generating a tracking error signal representing a tracking error in respect of a light beam scanning the record track on a record medium from which a reproduced information signal is obtained. A servocontrol amplifier is supplied with the tracking error signal and produces a drive signal in response to the tracking error signal. The drive signal is supplied to a driving device for tracking servocontrol. A defect detector detects a variation in the reproduced information signal resulting from a defect on the recorded surface of the record medium, and a control circuit reduces the gain of the servocontrol amplifier when a predetermined detection output is obtained from the defect detector. This prevents the drive signal supplied to the driving device from being harmfully affected by the defect on the recorded surface of the record medium.