Granted Patent B2

US 7,065,018 · App. 09/951,108 · Granted Jun 20, 2006

Abstract

Claims (31)

1. A method for controlling the spin speed of motor, said method comprising:

receiving a physical sector address (PSA) value and recording a current time of receipt;

determining a time difference between the time of receipt and a previous time of receipt;

if the time difference is less than a maximum time difference, entering a database using a table index based on said PSA value; and

providing reference data from said database corresponding to said table index to provide an output for providing a control effort.

2. The method of claim 1 , wherein said entering said database comprises entering a first resolution table or a second resolution table based upon said table index.

3. The method of claim 2 , wherein said reference data comprises a proportional gain (Kp), an integrator gain (Ki) and a reference period.

4. The method of claim 1 , further comprising calculating said table index by dividing the PSA value by a number of PSA data entries listed per row in said database.

5. The method of claim 1 , wherein said receiving of said PSA value occurs every 2 milliseconds.

6. The method of claim 5 , wherein said receiving comprises detecting an age of said PSA value by comparing the receipt time for a PSA value previously received to a present time.

7. The method of claim 6 , comprises updating said PSA value by one for every 2 milliseconds of time passed when said comparison yields a difference of less than about 48 milliseconds.

8. The method of claim 1 , wherein said database comprises a lookup table module including a first table section corresponding to PSA values from a first portion of an optical medium and a second table section corresponding to PSA values from a second portion of said optical medium.

9. A method for controlling spin velocity of an optical medium comprising:

reading a physical sector address (PSA) from an optical medium;

detecting an age of said PSA by comparing a first time stamp for said PSA to the present time;

if the age is less than a maximum age, calculating a table index based on said PSA;

entering a lookup table module to acquire reference data; and

maintaining a constant data rate transfer from said optical medium for a range of PSAs.

10. The method of claim 9 , further comprising updating said PSA by one for every 2 milliseconds of time passed when about 48 milliseconds have passed since said reading of said PSA.

11. The method of claim 9 , wherein said reference data comprises a proportional gain (Kp), an integrator gain (Ki) and a reference period.

12. The method of claim 9 , wherein said calculating said table index comprises dividing the PSA by a number of PSA data entries listed per row in said lookup table module.

13. The method of claim 9 , wherein said reading of said PSA value occurs every 2milliseconds.

14. The method of claim 9 , wherein said lookup table module comprises a first table section corresponding to a PSA from a first portion of said optical medium and a second table section corresponding to a PSA from a second portion of said optical medium.

15. A system for controlling spin velocity of an optical medium comprising:

means for reading a physical sector address (PSA) from an optical medium;

means for calculating a table index based on said PSA;

means for detecting an age of said PSA by comparing a time stamp for said PSA to a present time;

means for entering a lookup table module to acquire reference data; and

means for maintaining a constant data rate transfer from said optical medium for a range of PSAs.

16. The method of claim 15 , wherein said lookup table module comprises a first table section corresponding to a PSA from a first portion of said optical medium and a second table section corresponding to a PSA from a second portion of said optical medium.

17. The system of claim 15 , wherein said reference data comprises a proportional gain (Kp), an integrator gain (Ki) and a reference period.

Assignments (9)