Digital tracking servo system with multi-track seek
AssigneeDPHI Acquisitions, Inc.
InventorRon J. Kadlec
Life of this patent
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Abstract
A servo system with a multi-track seek algorithm is presented. The multi-track seek algorithm detects zero crossings in a tracking error signal, counts the number of zero crossings to form a count, and calculates a reference velocity from the count. The algorithm also determines a time period between successive zero crossings, calculates a velocity from the time period, calculates a difference signal between the reference velocity and the velocity, and adjusts the control signal so that the velocity follows the reference velocity. The reference velocity can follow a velocity profile with acceleration portions, coasting portions, and deceleration portions which move an optical pick-up unit from a starting position to a target position.
Claims15
A method of multi-track seeking, comprising:
- calculating a tracking error signal from digitized optical signals from an optical pick-up unit;
- detecting zero crossings in the tracking error signal;
- counting the number of zero crossings to form a count;
- calculating a reference velocity from the count;
- determining a time period between successive zero crossings;
- calculating a velocity from the time period;
- calculating a difference signal between the reference velocity and the velocity;
- adjusting a control signal so that the velocity follows the reference velocity;
- and
- applying the control signal to an actuator coupled to adjust the position of the optical pick-up unit over an optical media.
A servo system, comprising:
- an optical pick-up unit positioned over an optical media;
- an analog processor coupled to receive signals from detectors in the optical pick-up unit and provide digital signals;
- at least one processor coupled to receive the digital signals, the processor calculating a control signal;
- and
- a driver coupled to control a position of the optical pick-up unit in response to the control signal,
- wherein the at least one processor executes a multi-track seek algorithm that
- calculates a tracking error signal from the digital signals,
- detects zero crossings in the tracking error signal,
- counts the number of zero crossings to form a count,
- calculates a reference velocity from the count,
- determines a time period between successive zero crossings,
- calculates a velocity from the time period,
- calculates a difference signal between the reference velocity and the velocity, and
- adjusts the control signal so that the velocity follows the reference velocity.
A servo system, comprising:
- means for receiving optical signals;
- means for calculating a tracking error signal;
- and
- means for performing a multi-track seek operation.
Dependencies are inferred from the claim text.