Reducing the effect of spiral sync marks in non-coherent repeatable runout
View Patent ↗A method for collecting position information in a disk drive having a read head and a disk with a set of spirals formed thereon includes: while the read head crosses a first spiral included in the set of spirals, opening a first frame integration window; while the first frame integration window is open, generating first signals with the read head as the read head crosses over a first set of magnetic transitions; closing the first frame integration window; after closing the first frame integration window, generating second signals with the read head as the read head crosses over a second set of magnetic transitions; and determining a radial position of the read head by integrating amplitudes of the first signals, wherein the first set includes magnetic transitions having a first polarity, and the second set includes two or more magnetic transitions having a second polarity.
1. A method for collecting position information in a disk drive having a read head and a disk with a set of spirals formed thereon, the method comprising:
while the read head crosses a first spiral included in the set of spirals, opening a first frame integration window;
while the first frame integration window is open, generating first signals with the read head as the read head crosses over a first set of magnetic transitions;
closing the first frame integration window;
after closing the first frame integration window, generating second signals with the read head as the read head crosses over a second set of magnetic transitions; and
determining a radial position of the read head by integrating amplitudes of the first signals,
wherein the first set includes magnetic transitions having a first polarity, and the second set includes two or more magnetic transitions having a second polarity.
2. The method of claim 1 , further comprising, after the read head crosses the second set of magnetic transitions and while the read head crosses the first spiral, opening a second frame integration window, and while the second frame integration window is open, generating additional first signals with the read head as the read head crosses over a third set of magnetic transitions.
3. The method of claim 2 , wherein:
the third set includes magnetic transitions having the first polarity and magnetic transitions having the second polarity; and
the magnetic transitions included in the third set and having the second polarity are adjacent to the second set of magnetic transitions.
4. The method of claim 1 , further comprising determining the radial position of the read head by determining a timing associated with the read head based on the second signals.
5. The method of claim 1 , wherein the first set includes magnetic transitions having the first polarity and magnetic transitions having the second polarity which are adjacent to the second set of magnetic transitions, and the second set includes no magnetic transitions having the first polarity.
6. The method of claim 5 , wherein the magnetic transitions having the second polarity that are adjacent to the second set of magnetic transitions are included in an end portion of the first frame integration window.
7. The method of claim 1 , wherein the first frame integration window is included in a plurality of frame integration windows associated with the first spiral, and the first signals are generated by the read head as the read head crosses over magnetic transitions while the first frame integration window is open.
8. The method of claim 1 , wherein opening the first frame integration window comprises opening the first frame integration window based on a start time for the first frame integration window that is associated with servoing the read head at a first data storage track while the read head crosses the first spiral.
9. The method of claim 8 , further comprising determining the start time based on timing signals generated with the read head while servoing the read head at a second data storage track.
10. The method of claim 9 , wherein the second data storage track is radially adjacent to the first data storage track.
11. The method of claim 1 , wherein closing the first frame integration window comprises closing the first frame integration window based on an end time for the first frame integration window that is associated with servoing the read head at a first data storage track while the read head crosses the first spiral.
12. The method of claim 11 , further comprising determining the end time based on timing signals generated with the read head while servoing the read head at a second data storage track.
13. The method of claim 12 , wherein the second data storage track is radially adjacent to the first data storage track.
14. The method of claim 1 , further comprising performing a servo self-writing process on the disk based on the first signals and the second signals.
15. A disk drive, comprising:
a read head;
a disk with a set of spirals formed thereon; and
a controller configured to perform the steps of:
while the read head crosses a first spiral included in the set of spirals, opening a first frame integration window;
while the first frame integration window is open, generating first signals with the read head as the read head crosses over a first set of magnetic transitions;
closing the first frame integration window;
after closing the first frame integration window, generating second signals with the read head as the read head crosses over a second set of magnetic transitions; and
determining a radial position of the read head by integrating amplitudes of the first signals,
wherein the first set includes magnetic transitions having a first polarity, and the second set includes two or more magnetic transitions having a second polarity.
16. The disk drive of claim 15 , wherein the steps further comprise: after the read head crosses the second set of magnetic transitions and while the read head crosses the first spiral, opening a second frame integration window, and while the second frame integration window is open, generating additional first signals with the read head as the read head crosses over a third set of magnetic transitions.
17. The disk drive of claim 16 , wherein:
the third set includes magnetic transitions having the first polarity and magnetic transitions having the second polarity; and
the magnetic transitions included in the third set and having the second polarity are adjacent to the second set of magnetic transitions.
18. The disk drive of claim 15 , wherein the first set includes magnetic transitions having the first polarity and magnetic transitions having the second polarity which are adjacent to the second set of magnetic transitions, and the second set includes no magnetic transitions having the first polarity.
19. The disk drive of claim 18 , wherein the magnetic transitions having the second polarity that are adjacent to the second set of magnetic transitions are included in an end portion of the first frame integration window.
20. The disk drive of claim 15 , wherein opening the first frame integration window comprises opening the first frame integration window based on a start time for the first frame integration window that is associated with servoing the read head at a first data storage track while the read head crosses the first spiral.