US3357003A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single channel quaternary magnetic recording system
Assignee: International Business Machines Corp
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Filing: 1964-12-28
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Granted: 1967-12-05
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Expires: 1984-12-28
Abstract
No abstract record available.
Inventors
- 👤 Steven J Macarthur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 18:07
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/14; G11B20/1488
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
122 words
THE METHOD OF RECORDING DIGITAL DATA AT A SELECTED DATA RATE ON A SINGLE RECORD TRACK OF A MAGNETIC MEDIUM COMPRISING THE STEPS OF ESTABLISHING A SUCCESSION OF DATA POINTS THAT ARE REGULARLY SPACED IN TIME, ESTABLISHING A SUCCESSION OF REGULARLY SPACED TRANSITION POINTS, EACH TRANSITION POINT HAVING A FIXED TIME OF OCCURRENCE WITHIN THE DATA INTERVAL DEFINED BY A PAIR OF SUCCESSIVE DATA POINTS, ESTABLISHING A MAGNETIZATION CONDITION AT THE DATA POINTS REPRESENTING EITHER (1) STEADY STATE MAGNETIZATION OF EITHER POLARITY OF (2) A SHARP TRANSITION OF EITHER POLARITY DIRECTION BETWEEN THE STEADY STATE CONDITIONS, THUS TO PROVIDE A QUATERNARY CODE, AND SELECTIVELY INTRODUCING TRANSITIONS AT THE TRANSITION POINTS IN ACCORDANCE WITH THE SUCCEEDING MAGNETIZATION CONDITION AT THE NEXT DATA POINT.
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) | 1970-12-04 | 1971-06-05 | 1971-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-12-04 | 1975-06-05 | 1975-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-12-04 | 1979-06-05 | 1979-12-05 | $7700.00 | Window Closed / Lapsed |