Patent
Tracking servocontrol circuits for reducing gain to avoid tracking defect in an optical reproducing apparatus
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TLDR
In this paper, a tracking servocontrol circuit for optical reproducing is described, which consists of a signal generator for generating a tracking error signal representing the tracking error in respect of a light beam scanning the record track on a record medium from which a reproduced information signal is obtained.Abstract:
A 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.read more
Citations
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Method and apparatus for correcting the loop gain of a servo loop in accordance with measurements during open-loop operation
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TL;DR: In this article, the peak-to-peak value of an error signal in the servo loop is detected while the optical pickup is being driven perpendicularly to the disk in focusing or transversely to the disks in tracking.
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William Wai-Chung Chow,Alan August Fennema,Benjain Carmel Fiorino,Ian Edward Henderson,Kadlec Ronald James,Spencer Donald Roberts +5 more
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References
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Patent
Tracking system for optical record medium
TL;DR: In this paper, the tracking error signal represents the deviation of a scanning reading beam from the centerline of the selected track, and couples this error signal to a movable tracking mirror to form a servo for controllably positioning the beam in alignment with the track.
Patent
Scanning beam control system
Robert M. Shoji,John S. Chudy +1 more
TL;DR: In this paper, the authors present a control system for controllably adjusting a prescribed characteristic of a beam scanning a record medium, which is embodied in a tracking apparatus for use in a playback system for recovering information from a selected recording track on an optical record medium such as a video disc.
Patent
Focus servo control system for automatically adjusting a relative distance between an objective lens unit and a recording surface of an optical recording medium
TL;DR: In this paper, a focus servo control system for adjusting a relative distance between an objective lens unit and a recording surface of an optical recording medium is presented. But the focus control system includes a component adapted to be energized by an electrical current to shift the object lens perpendicularly to the recording surface, a component for detecting the laser light reflected from the recorded surface, and a servo amplifier adapted to amplify the error signal thereby to produce the electric current for energizing the lens shifting components, and in order to avoid wasteful electrical power consumption and the mechanical noises.
Patent
Tracking servo signal generating device in an apparatus for reading recorded information
TL;DR: In this paper, a tracking servo signal generating device in a tracked servo control system in a recorded information reading apparatus adapted to deviate an information detecting point in the direction perpendicular to a target recording track on a recording medium is presented.
Patent
Method and system for a disc player tracking servo
TL;DR: In this article, a tracking error signal indicative of an amount of deviation of an information pickup medium such as a focused spot of a scanning beam of light from a target track of the recording disc being scanned is amplified with a gain which is varied as the pickup medium is displaced radially of the disc between an outer peripheral area and a central area.