Granted Patent B2

US 7,260,031 · App. 09/950,376 · Granted Aug 21, 2007

Abstract

Claims (32)

1. A method of performing a one-track jump, comprising:

holding a control signal from a tracking servo system constant including filtering the control signal with a low pass filter and sampling and holding an output signal of the low pass filter, the control signal controlling the motion of an optical pick-up unit over a first track on an optical media;

adding an acceleration control signal to the control signal for a first period of time;

adding a deceleration control signal to the control signal for a third period of time subsequent to an expiration of a second period of time and an expiration of the first period of time; and

freeing the control signal to close tracking on a target track separated from the first track by one track subsequent to an expiration of the third period of time.

2. The method of claim 1 , wherein the acceleration control signal is a square-wave pulse.

3. The method of claim 1 , wherein the acceleration control signal is smoothly shaped.

4. The method of claim 3 , wherein the shape is a sine wave.

5. The method of claim 1 , wherein the deceleration control signal is a square-wave pulse.

6. The method of claim 1 , wherein the deceleration control signal is smoothly shaped.

7. The method of claim 6 , wherein the shape is a sine wave.

8. The method of claim 1 , wherein the second period of time is determined by when a tracking error signal crosses a half track point.

9. The method of claim 1 , wherein freeing the control signal includes delaying for a fourth period of time before closing tracking.

10. The method of claim 9 , wherein the fourth period of time is sufficient to allow most transient effects to substantially decay.

11. The method of claim 1 , further including initializing a tracking phase lead in a tracking servo system.

12. The method of claim 1 , further including holding a focus control effort from a focus servo system constant; and freeing the focus control effort before freeing the control signal.

13. A servo system, comprising:

an optical pick-up unit;

an analog-to-digital 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 tracking position of the optical pick-up unit in response to the control signal,

wherein the at least one processor executes a one-track jump algorithm that

holds the control signal constant, the control signal controlling the motion of an optical pick-up unit over a first track on an optical media;

adds an acceleration control signal to the control signal for a first period of time;

adds a deceleration control signal to the control signal for a third period of time upon an expiration of the first period of time and an expiration of a second period of time;

frees the control signal to close tracking on a target track separated from the first track by one track upon an expiration of the third period of time;

filters a focus control signal with a low pass filter to form a filtered focus control signal; and

samples and holds the filtered control signal the one-track jump algorithm is being executed.

14. The system of claim 13 , wherein the second period of time is sufficient that a tracking error signal indicates a half-track crossing.

15. The system of claim 13 , wherein the algorithm also includes a fourth delay period before closing tracking.

16. The system of claim 15 , wherein the algorithm also holds a focus control effort constant.

17. The system of claim 15 , wherein the algorithm also initializes a phase lead in a tracking control effort.

Assignments (8)