US6288858B1
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Method for improving magnetic recording at high data rates for waveforms having a burst of transitions
Assignee: International Business Machines Corp
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Filing: 1999-06-09
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Granted: 2001-09-11
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Expires: 2019-06-09
Abstract
Abstract A method and a device for write precompensating a data pattern for recording the pattern on a magnetic storage medium at high data rates. A first predetermined write-precompensation delay is applied to the second transition of a burst of transitions of the data pattern. A second predetermined write-precompensation delay is applied to the last transition of a burst. A third predetermined write-precompensation delay is applied to the middle transitions, if any, of a burst. When the burst is a dibit, the application of the second and third predetermined write-precompensation delays is omitted and the first predetermined write-precompensation delay is based on the burst being a dibit. When the burst is a tribit, the application of the second predetermined write-precompensation delay is omitted and the first and third predetermined write-precompensation delays are based on the burst being a tribit. A fourth predetermined write-precompensation delay is applied to the transitions in the data pattern that are not part of a burst of transitions.
Inventors
- 👤 Patrick Clinton Arnett
- 👤 David Cheekit Cheng
- 👤 Radley Wahl Olson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:54
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/02; G11B5/09; G11B20/00; G11B20/10; G11B20/10009; G11B5/012
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
218 words
A method for write-precompensating a waveform for magnetically recording the waveform on a magnetic medium, the method comprising steps of: applying a first predetermined write-precompensation delay ε l to a second transition of a burst of transitions of the waveform, the burst of transitions having at least four transitions, the second transition being immediately subsequent to a first transition of the burst of transitions, each transition of the burst corresponding to a tick of a write clock having a period T, the first predetermined write-precompensation delay ε l delaying the second transition of the burst of transitions with respect to the tick of the write clock corresponding to the second transition; applying a second predetermined write-precompensation delay ε t to a last transition of the burst, the second predetermined write-precompensation delay ε t delaying the last transition of the burst with respect to the tick of the write clock corresponding to the last transition; and applying a third predetermined write-precompensation delay ε m to all transitions of the burst of transitions that are subsequent to the second transition except the last transition of the burst, the third predetermined write-precompensation delay ε m delaying each transition of the burst that is subsequent to the second transition with respect to a tick of the write clock corresponding to the transition.
Claim 2
Independent Claim
218 words
A method for write-precompensating a waveform for magnetically recording the waveform on a magnetic medium, the method comprising steps of: applying a first predetermined write-precompensation delay ε l to a second transition of a burst of transitions of the waveform, the burst of transitions having at least four transitions, the second transition being immediately subsequent to a first transition of the burst of transitions, each transition of the burst corresponding to a tick of a write clock having a period T, the first predetermined write-precompensation delay ε l delaying the second transition of the burst of transitions with respect to the tick of the write clock corresponding to the second transition; applying a second predetermined write-precompensation delay ε t to a last transition of the burst, the second predetermined write-precompensation delay ε t delaying the last transition of the burst with respect to the tick of the write clock corresponding to the last transition; and applying a third predetermined write-precompensation delay ε m to all transitions of the burst of transitions that are subsequent to the second transition except the last transition of the burst, the third predetermined write-precompensation delay ε m delaying each transition of the burst that is subsequent to the second transition with respect to a tick of the write clock corresponding to the transition.
Claim 3
Dependent Claim
11 words
The method according to claim 1 , wherein ε m >0.
Claim 4
Dependent Claim
13 words
The method according to claim 2 , wherein ε m <ε l .
Claim 5
Dependent Claim
13 words
The method according to claim 2 , wherein ε m <ε t .
Claim 6
Dependent Claim
68 words
The method according to claim 1 , wherein the waveform further includes an isolated transition, the method further comprising a step of applying a fourth predetermined write-precompensation delay ε iso to the isolated transition, the fourth predetermined write-precompensation delay ε iso delaying the isolated transition with respect to a tick of the write clock corresponding to the isolated transition and recentering the burst relative a detection timing window.
Claim 7
Dependent Claim
215 words
The method according to claim 1 , wherein the burst of transitions has at least six transitions, and wherein the step of applying the third predetermined write-precompensation delay ε m applies the third predetermined write-precompensation delay ε m to all transitions of the burst of transitions that are subsequent to a third transition of the burst of transitions except the penultimate and the last transition of the burst, the third transition being immediately subsequent to the second transition, the third predetermined write-precompensation delay ε m delaying each transition of the burst that is subsequent to the third transition except the penultimate and the last transition with respect to a tick of the write clock corresponding to the transition the method further comprising steps of: applying a fifth predetermined write-precompensation delay ε a to the third transition of the burst of transitions, the fifth predetermined write-precompensation delay ε a delaying the third transition of the burst of transitions with respect to the tick of the write clock corresponding to the third transition; and applying a sixth predetermined write-precompensation delay ε z to the penultimate transition of the burst, the sixth predetermined write-precompensation delay ε z delaying the penultimate transition of the burst with respect to the tick of the write clock corresponding to the penultimate transition.
Claim 8
Dependent Claim
11 words
The method according to claim 6 , wherein ε m >0.
Claim 9
Dependent Claim
13 words
The method according to claim 7 , wherein ε m ≦ε a .
Claim 10
Dependent Claim
13 words
The method according to claim 7 , wherein ε m ≦ε z .
Claim 11
Dependent Claim
13 words
The method according to claim 7 , wherein ε m <ε t .
Claim 12
Dependent Claim
209 words
The method according to claim 6 , wherein the burst of transitions has at least eight transitions, and wherein the step of applying the third predetermined write-precompensation delay ε m applies the third predetermined write-precompensation delay ε m to all transitions of the burst of transitions that are subsequent to a fourth transition of the burst of transitions except the antepenultimate, penultimate and the last transitions of the burst, the fourth transition being immediately subsequent to the third transition, the third predetermined write-precompensation delay ε m delaying each transition of the burst that is subsequent to the fourth transition with respect to a tick of the write clock corresponding to the transition, the method further comprising steps of: applying a seventh predetermined write-precompensation delay ε b to the fourth transition of the burst of transitions, the seventh predetermined write-precompensation delay ε b delaying the fourth transition of the burst of transitions with respect to the tick of the write clock corresponding to the fourth transition; and applying an eighth predetermined write-precompensation delay ε y to the antepenultimate transition of the burst, the eighth predetermined write-precompensation delay ε y delaying the antepenultimate transition of the burst with respect to the tick of the write clock corresponding to the antepenultimate transition.
Claim 13
Dependent Claim
11 words
The method according to claim 11 , wherein ε m >0.
Claim 14
Dependent Claim
13 words
The method according to claim 12 , wherein ε m ≦ε b .
Claim 15
Dependent Claim
13 words
The method according to claim 12 , wherein ε m ≦ε y .
Claim 16
Dependent Claim
13 words
The method according to claim 12 , wherein ε m ≦ε z .
Claim 17
Dependent Claim
13 words
The method according to claim 12 , wherein ε m <ε t .
Claim 18
Dependent Claim
53 words
The method according to claim 1 , wherein the waveform further includes a dibit, the method further comprising a step of applying a ninth predetermined write-precompensation delay ε l′ to a second transition of the dibit with respect to the tick of the write clock corresponding to the second transition of the dibit.
Claim 19
Dependent Claim
13 words
The method according to claim 17 , wherein ε l′ =ε l .
Claim 20
Dependent Claim
44 words
The method according to claim 1 , wherein the waveform further includes a tribit, the method further comprising a step of applying a tenth predetermined write-precompensation delay ε m′ to a third transition of the tribit, wherein 0≦ε m′ ≦max(ε l ,ε t ).
Claim 21
Independent Claim
245 words
A device for write-precompensating a waveform for magnetically recording the waveform on a magnetic medium, the device comprising: a shift register receiving the waveform, the waveform having a plurality of transitions; a pattern detector detecting a predetermined pattern of transitions of the waveform; and a delay device generating a first predetermined write-precompensation delay ε l for a second transition of a burst of transitions of the waveform, the burst of transitions having at least four transitions, the second transition being immediately subsequent to a first transition of the burst of transitions, each transition of the burst corresponding to a tick of a write clock having a period T, the first predetermined write-precompensation delay ε l delaying the second transition of the burst of transitions with respect to the tick of the write clock corresponding to the second transition, generating a second predetermined write-precompensation delay ε t for a last transition of the burst, the second predetermined write-precompensation delay ε t delaying the last transition of the burst with respect to the tick of the write clock corresponding to the last transition, and generating a third predetermined write-precompensation delay ε m for all transitions of the burst of transitions that are subsequent to the second transition except the last transition of the burst, the third predetermined write-precompensation delay ε m delaying each transition of the burst that is subsequent to the second transition with respect to a tick of the write clock corresponding to the transition.
Claim 22
Independent Claim
245 words
A device for write-precompensating a waveform for magnetically recording the waveform on a magnetic medium, the device comprising: a shift register receiving the waveform, the waveform having a plurality of transitions; a pattern detector detecting a predetermined pattern of transitions of the waveform; and a delay device generating a first predetermined write-precompensation delay ε l for a second transition of a burst of transitions of the waveform, the burst of transitions having at least four transitions, the second transition being immediately subsequent to a first transition of the burst of transitions, each transition of the burst corresponding to a tick of a write clock having a period T, the first predetermined write-precompensation delay ε l delaying the second transition of the burst of transitions with respect to the tick of the write clock corresponding to the second transition, generating a second predetermined write-precompensation delay ε t for a last transition of the burst, the second predetermined write-precompensation delay ε t delaying the last transition of the burst with respect to the tick of the write clock corresponding to the last transition, and generating a third predetermined write-precompensation delay ε m for all transitions of the burst of transitions that are subsequent to the second transition except the last transition of the burst, the third predetermined write-precompensation delay ε m delaying each transition of the burst that is subsequent to the second transition with respect to a tick of the write clock corresponding to the transition.
Claim 23
Dependent Claim
11 words
The device according to claim 20 , wherein ε m ≧0.
Claim 24
Dependent Claim
13 words
The device according to claim 21 , wherein ε m <ε l .
Claim 25
Dependent Claim
13 words
The device according to claim 21 , wherein ε m <ε t .
Claim 26
Dependent Claim
64 words
The device according to claim 20 , wherein the waveform further includes an isolated transition, the delay device generating a fourth predetermined write-precompensation delay ε iso to the isolated transition, the fourth predetermined write-precompensation delay ε iso delaying the isolated transition with respect to a tick of the write clock corresponding to the isolated transition and recentering the burst relative a detection timing window.
Claim 27
Dependent Claim
205 words
The device according to claim 20 , wherein the burst of transitions has at least six transitions, wherein the delay device generates the third predetermined write-precompensation delay ε m for all transitions of the burst of transitions that are subsequent to a third transition of the burst of transitions except the penultimate and the last transition of the burst, the third transition being immediately subsequent to the second transition, the third predetermined write-precompensation delay ε m delaying each transition of the burst that is subsequent to the third transition except the penultimate and the last transition with respect to a tick of the write clock corresponding to the transition, and wherein the delay device generates a fifth predetermined write-precompensation delay ε a for the third transition of the burst of transitions, the fifth predetermined write-precompensation delay ε a delaying the third transition of the burst of transitions with respect to the tick of the write clock corresponding to the third transition, and generates a sixth predetermined write-precompensation delay ε z for the penultimate transition of the burst, the sixth predetermined write-precompensation delay ε z delaying the penultimate transition of the burst with respect to the tick of the write clock corresponding to the penultimate transition.
Claim 28
Dependent Claim
11 words
The device according to claim 25 , wherein ε m ≧0.
Claim 29
Dependent Claim
13 words
The device according to claim 26 , wherein ε m ≦ε a .
Claim 30
Dependent Claim
13 words
The device according to claim 26 , wherein ε m ≦ε z .
Claim 31
Dependent Claim
13 words
The device according to claim 26 , wherein ε m <ε t .
Claim 32
Dependent Claim
199 words
The device according to claim 25 , wherein the burst of transitions has at least eight transitions, wherein the delay device generates the third predetermined write-precompensation delay ε m for all transitions of the burst of transitions that are subsequent to a fourth transition of the burst of transitions except the antepenultimate, penultimate and the last transitions of the burst, the fourth transition being immediately subsequent to the third transition, the third predetermined write-precompensation delay ε m delaying each transition of the burst that is subsequent to the fourth transition with respect to a tick of the write clock corresponding to the transition, and wherein the delay device generates a seventh predetermined write-precompensation delay ε b for the fourth transition of the burst of transitions, the seventh predetermined write-precompensation delay ε b delaying the fourth transition of the burst of transitions with respect to the tick of the write clock corresponding to the fourth transition, and generates an eighth predetermined write-precompensation delay ε y for a antepenultimate transition of the burst, the eighth predetermined write-precompensation delay ε y delaying the antepenultimate transition of the burst with respect to the tick of the write clock corresponding to the antepenultimate transition.
Claim 33
Dependent Claim
11 words
The device according to claim 30 , wherein ε m ≧0.
Claim 34
Dependent Claim
13 words
The device according to claim 31 , wherein ε m ≦ε b .
Claim 35
Dependent Claim
13 words
The device according to claim 31 , wherein ε m ≦ε y .
Claim 36
Dependent Claim
13 words
The device according to claim 31 , wherein ε m ≦ε z .
Claim 37
Dependent Claim
14 words
The device according to claim 31 , wherein ε m 21 ε t .
Claim 38
Dependent Claim
70 words
The device according to claim 20 , wherein the waveform further includes a dibit, and wherein the delay device generates a ninth predetermined write-precompensation delay ε t′ for a second transition of the dibit with respect to the tick of the write clock corresponding to the second transition of the dibit instead of generating the first predetermined write-precompensation delay ε l and the second predetermined write-precompensation delay ε t .
Claim 39
Dependent Claim
13 words
The device according to claim 36 , wherein ε l′ =ε l .
Claim 40
Dependent Claim
72 words
The device according to claim 20 , wherein the waveform further includes a tribit, wherein the delay device generates a tenth predetermined write-precompensation delay ε m′ for a third transition of the dibit instead of generating the method further comprising a step of replacing the step of applying the second predetermined write-precompensation delay ε t to a third transition of the tribit, and wherein 0≦ε m′ ≦max(ε l , ε t ).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-09-10 | 2005-03-12 | 2005-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-09-10 | 2009-03-12 | 2009-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-09-10 | 2013-03-12 | 2013-09-11 | $7700.00 | Window Closed / Lapsed |