Patent
Focus and tracking servo decoupling system
Keith Allen Bates,Nhan X. Bui,Delbert Hansen +2 more
- 05 Nov 1993
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TL;DR: In this paper, the authors proposed a circuit for electronically compensating for optical and mechanical instabilities induced into the focus control and tracking control servo circuits of an optical disk apparatus.
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Abstract: A circuit for electronically compensating for optical and mechanical instabilities induced into the focus control and tracking control servo circuits of an optical disk apparatus. The circuit contains a filter and a variable gain amplifier for passing a tracking error signal compensation component at a selected frequency within the range of frequencies in which mechanical resonance is significant and at a magnitude equal to the focus error signal component at that frequency. The result is the electronic elimination of optical feedthrough at mechanically resonating frequencies. A calibration circuit establishes the compensation component magnitude for each optical disk inserted into the apparatus.
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Citations
Patent
Integrated optical/electronic circuits and associated methods of simultaneous generation thereof
Shrenik Deliwala
- 15 May 2002
TL;DR: In this article, a method for forming a hybrid active electronic and optical circuit (103) using a lithography mask (6312) is disclosed. But the method is not suitable for the case where the active electronic device and the optical device are on the same SOI wafer.
72
Patent
Repeatable runout compensation using a learning algorithm with scheduled parameters
YangQuan Chen,LeeLing Tan,KianKeong Ooi,Qiang Bi,Kokhiang Cheong +4 more
- 21 Jan 2000
TL;DR: In this paper, a method and apparatus for compensating for written-in repeatable runout in a disc drive is provided, where compensation values are determined through an iterative learning process in which parameters of the learning process such as learning gain, servo loop gain, etc. are functions of the iteration number.
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Patent
Compensation for repeatable run-out error
John C. Morris,Brian R. Pollock,Timothy F. Ellis +2 more
- 09 Aug 1999
TL;DR: In this paper, a method and apparatus for compensating for repeatable run-out errors in a disc drive is described, where the compensation is created by determining transfer function values for a servo loop in the drive as well as a sequence of repeatable running-out values.
56
Patent
Repeatable runout compensation using iterative learning control in a disc storage system
Qiang Bi,Gomez Kevin A,YangQuan Chen,KianKeong Ooi +3 more
- 29 Dec 1999
TL;DR: In this article, a disc storage system is provided which includes a servo control loop for compensating for repeatable runout, which is compensated using table entries of the form Comp Value(k+1), where K is a learning rate; k is iteration number Φ(z) is a filter and RRO(k) is the repeatability runout error.
52
Patent
Virtual tracks for repeatable runout compensation
Brian R. Pollock,Alexei H. Sacks,Brian W. Sudman,James H. McGlennen,Reed David Hanson +4 more
- 08 Dec 2000
TL;DR: In this article, the authors proposed a repeatable runout (RRO) compensation of servo control systems that can be used in disc drives or spin-stands, where the RRO relates to eccentricity between servo tracks, which were written onto a disc prior to the installation of the disc into the disc drive or spinstand, and an axis of rotation of a disc.
20
References
Patent
Servo system gain compensation method for magneto-optic disk drives
Gregory V. Hofer,James C. McDonald +1 more
- 31 Oct 1988
TL;DR: In this paper, a programmable digital signal processor in an optical disk drive is used to compensate tracking and/or focus servo system gain each time a new disk is inserted.
69
Patent
Servo circuit for a signal reproducing apparatus
Shigeki Inoue,Takao Arai,Yukio Fukui,Takashi Takeuchi,Harushige Nakagaki,Masafumi Nagamura,Baba Tatsuo +6 more
- 30 May 1983
TL;DR: In this paper, a servo circuit for a signal reproducing apparatus for reproducing signals from a record medium such as a disc utilizing an optical pickup is described, wherein a variable gain amplifier is arranged in a servosupported loop between a pickup and an actuator so that the pickup is caused to track a signal track in accordance with the servo error signal produced by the variable gain amplifiers.
42
Patent
Focus and tracking error detector apparatus for optical and magneto-optical information storage systems
Frank R. Whitehead,Alan B. Marchant +1 more
- 30 Oct 1989
TL;DR: In this article, a focus and tracking error optical servo detector is described in which focus error offset caused by beam transition between track and non-track areas is substantially reduced by shaping the detector element areas so as to derive servo signals from substantially only the overlap lobes between the zeroth order diffraction beam and the plus and minus first-order diffraction beams in the optical readout beam from the recording element.
35
Patent
Acquiring a best focus using a focus signal offset
Alan August Fennema,Robert Alan Klem +1 more
- 28 Sep 1990
TL;DR: A focus acquisition system includes providing a focus offset and changing the offset symmetrically for each measurement cycle as discussed by the authors, where the amplitudes of the readback or tracking error signal are sensed and compared.
26
Patent
Beam focus control system for optical record carrier scanning apparatus
Martinus Petrus Maria Bierhoff,Job F. P. van Mil +1 more
- 16 May 1989
TL;DR: In this article, a focus control system for optical record carrier scanning apparatus includes a mechanical actuator (13) for moving the focus of the scanning beam relative to a recording layer of the record carrier, a focus error detection circuit (15, 16, 17) for generating a focus-error signal (FE), and a control circuit (26) for producing a first control signal (AS') for the actuator, which is proportional to the focus error signal.
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