US4149200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transducer positioning system
Assignee: Unisys Corp
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Filing: 1977-10-31
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Granted: 1979-04-10
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Expires: 1997-10-31
Abstract
Abstract Principal embodiment teaches method and apparatus for radial positioning of a magnetic recording transducer relative to the concentric tracks of a rotatable magnetic disk having work data and servo data interspersed in alternate sectors along each track. The servo data sectors comprise repeating groups of servo tracks used to provide coarse and fine radial positioning signals for the transducer relative to the work data tracks. The servo system control hard-positioning carriage means [to seek target track and keep transducer gap "centered" during Reading and Writing operations] and also provides timing information (synchronized clock signals, timing-decode) determined by the drive, rather than external means. An "embedded" format, rather than "dedicated", is used for laying down the servo information.
Inventors
- 👤 Daniel C. Card
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:47
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G11B5/59605; G11B5/59616; G11B5/54; G11B5/55; G11B5/5521; G11B5/5552; G11B5/5556; G11B5/556
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
82 words
In an improved magnetic recording system including multi-track magnetic records, at least a portion of each track thereon being recorded in "di-bit" mode, the combination therewith comprising: a di-bit detection array, said array including filter means adapted to essentially filter the detected di-bit pulse, rejecting "non-standard" waveforms and delay/subtract means adapted to delay portions of this pulse and perform a summation on the original and the delayed pulse forms, with associated polarity-rectification to generate a uni-polar output representing each di-bit transition recorded.
Claim 2
Dependent Claim
82 words
In an improved magnetic recording system including multi-track magnetic records, at least a portion of each track thereon being recorded in "di-bit" mode, the combination therewith comprising: a di-bit detection array, said array including filter means adapted to essentially filter the detected di-bit pulse, rejecting "non-standard" waveforms and delay/subtract means adapted to delay portions of this pulse and perform a summation on the original and the delayed pulse forms, with associated polarity-rectification to generate a uni-polar output representing each di-bit transition recorded.
Claim 3
Dependent Claim
26 words
The combination as recited in claim 1, wherein said detection array comprises a low-pass filter input stage followed by a delay/subtract stage and a clipping stage.
Claim 4
Dependent Claim
27 words
The combination as recited in claim 1, wherein said uni-polar di-bit outputs are also electronically screened by an envelope detector stage and an associated level detect stage.
Claim 5
Dependent Claim
42 words
The combination as recited in claim 1, wherein is also included actuator motor means and associated motor control means adapted to automatically "over-load" the motor and realize maximum acceleration therefrom normally, while automatically decelerating the motor once an over-load condition is sensed.
Claim 6
Dependent Claim
36 words
The combination as recited in claim 4, wherein said motor control means includes temperature monitor means adapted to sense a prescribed critical motor temperature and to responsively cause said control means to invoke said motor deceleration.
Claim 7
Dependent Claim
76 words
The combination as recited in claim 9, wherein there is also included a "DC Unsafe" arrangement adapted to monitor supply voltages and automatically indicate overall voltage aberrations, this arrangement comprising an array of weighted-impedance inputs, one from each supply voltage, plus compare means adapted to generate an output reflecting any said aberration in a weighted fashion, said compare means including maximum standard voltage and minimum standard voltage inputs adapted to set the range of said aberrations.
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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) | 1982-04-09 | 1982-10-09 | 1983-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-09 | 1986-10-09 | 1987-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-09 | 1990-10-09 | 1991-04-10 | $7700.00 | Window Closed / Lapsed |