US5153788A
Expired / Lapsed
US
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Method of recording and detecting servo information for positioning magnetic head
Assignee: Mitsubishi Electric Corp
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Filing: 1990-03-28
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Granted: 1992-10-06
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Expires: 2010-03-28
Abstract
Abstract Magnetization inversion data at different frequencies are recorded as part of servo information before and after an erasing gap between a data sector and a servo sector, the time interval between pulses read out from these magnetization inversion data is detected using a gap detection timer, and a timing for reading out servo information is obtained according to the result of detection by the gap detection timer.
Inventors
- 👤 Keiichi Nishikawa
- 👤 Shigemasa Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:29
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G11B5/59605; G11B5/59616; G11B19/00; G11B19/02; G11B19/04; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B27/3027
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
128 words
A method of recording and detecting servo information for positioning a magnetic head, comprising the steps of: alternately providing data sectors for recording data and servo sectors for recording servo information for positioning the head on a recording medium, recording detection information between said data and servo sectors, said detection information including preceding magnetization inversion data, succeeding magnetization inversion data, and an erasing gap between said preceding and succeeding magnetization inversion data; detecting a time interval between a pulse read out from said preceding magnetization inversion data and a pulse read out from said succeeding magnetization inversion data, said detection being accomplished by using a gap detection timer; and obtaining a timing for reading out said servo information from the result of detection by said gap detection timer.
Claim 2
Independent Claim
128 words
A method of recording and detecting servo information for positioning a magnetic head, comprising the steps of: alternately providing data sectors for recording data and servo sectors for recording servo information for positioning the head on a recording medium, recording detection information between said data and servo sectors, said detection information including preceding magnetization inversion data, succeeding magnetization inversion data, and an erasing gap between said preceding and succeeding magnetization inversion data; detecting a time interval between a pulse read out from said preceding magnetization inversion data and a pulse read out from said succeeding magnetization inversion data, said detection being accomplished by using a gap detection timer; and obtaining a timing for reading out said servo information from the result of detection by said gap detection timer.
Claim 3
Dependent Claim
22 words
The method according to claim 1, wherein obtaining said timing is providing a start signal and a count to a count setter.
Claim 4
Dependent Claim
26 words
The method according to claim 1, wherein said preceding and succeeding magnetization inversion data respectively include start and end signals indicative of their start and end.
Claim 5
Dependent Claim
69 words
The method according to claim 3, wherein said gap detection timer starts measurement of time from the appearance of said end signal of said preceding magnetization inversion data and effects time setting for obtaining said timing every time a time period T corresponding to the time interval of said preceding magnetization inversion data is passed after lapse of a time interval corresponding to the duration of said erasing gap.
Claim 6
Dependent Claim
24 words
The method according to claim 4, wherein said timing is started selectively by said start or end signal of said succeeding magnetization inversion data.
Claim 7
Dependent Claim
47 words
The method according to claim 1, wherein the preceding and succeeding magnetization data each has a time interval, the time interval of said succeeding magnetization inversion data being nT (n=2, 3, . . . ) where T is the time interval of said preceding magnetization inversion data.
Claim 8
Dependent Claim
29 words
The method according to claim 1, wherein a track address of a servo track provided in each said servo sector is provided subsequent to said succeeding magnetization inversion data.
Claim 9
Dependent Claim
39 words
The method according to claim 1 wherein said preceding magnetization inversion data is recorded at a first frequency and said succeeding magnetization inversion data is recorded at a second frequency, said first frequency being different from said second frequency.
Claim 10
Dependent Claim
28 words
The method according to claim 1 wherein the step of obtaining a timing includes the steps of providing a start signal and a count to a count setter.
Claim 11
Dependent Claim
72 words
The method according to claim 1, wherein said gap detection timer begins measuring time when it detects the ending signal of said preceding magnetization inversion data, and wherein said gap detection timer effects time setting for obtaining said timing every time a time period T corresponding to the time interval of said preceding magnetization inversion data is passed after lapse of a time interval corresponding to the duration of said erasing gap.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-06 | 1996-04-06 | 1996-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-06 | 2000-04-06 | 2000-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-06 | 2004-04-06 | 2004-10-06 | $7700.00 | Window Closed / Lapsed |