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US3911485A
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Self-clocking NRZ recording and reproduction system
Assignee: Arris Technology Inc
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Filing: 1974-08-09
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Granted: 1975-10-07
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Expires: 1994-08-09
Abstract
Abstract A magnetic recording and reading system wherein data is written into a magnetic medium in an NRZ code which is interrupted for the insertion of a guaranteed flux transition after each series of eight data cells. On readout, the guaranteed sync transition is used to generate a read clock for strobing purposes. The read clock is compensated to account for physical migration of the sync transition in the medium due to crowding effects or interaction with adjacent flux transitions.
Inventors
- 👤 Ronald P Mcgrath
- 👤 William A Bleher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:39
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1403
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
178 words
In a magnetic data storage system of the type having a magnetic storage medium wherein data is stored in the form of flux defining data cells and a sync flux level transition occurs every n data cells; read means responsive to the flux transitions in the magnetic storage medium to produce a corresponding signal waveform, timing means including an oscillator responsive to the occurrence of the sync transition to produce a timing signal sequence for determining the timing for reading said signal waveform, first compensation means connected between said read means and said timing means for effectively delaying the start of said timing signal sequence when the data cell preceding the sync transition does not contain a transition and the data cell following the sync transition does contain a transition, and second compensation means connected between said read means and said timing means for effectively advancing the start of said timing signal sequence when the data cell preceding the sync transition does contain a transition and the data cell following the sync transition does not contain a transition.
Claim 2
Dependent Claim
178 words
In a magnetic data storage system of the type having a magnetic storage medium wherein data is stored in the form of flux defining data cells and a sync flux level transition occurs every n data cells; read means responsive to the flux transitions in the magnetic storage medium to produce a corresponding signal waveform, timing means including an oscillator responsive to the occurrence of the sync transition to produce a timing signal sequence for determining the timing for reading said signal waveform, first compensation means connected between said read means and said timing means for effectively delaying the start of said timing signal sequence when the data cell preceding the sync transition does not contain a transition and the data cell following the sync transition does contain a transition, and second compensation means connected between said read means and said timing means for effectively advancing the start of said timing signal sequence when the data cell preceding the sync transition does contain a transition and the data cell following the sync transition does not contain a transition.
Claim 3
Dependent Claim
10 words
Apparatus as defined in claim 1 wherein n is eight.
References Cited (Backward Citations)
US3503059A
Cited
US3653009A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |