US4797872A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for reproducing data recorded on optical card
Assignee: Olympus Corp
•
Filing: 1987-08-13
•
Granted: 1989-01-10
•
Expires: 2007-08-13
Abstract
Abstract In a method of reproducing data recorded on an optical card in such a manner that distances between successive pits are modulated in accordance with the data, the optical card and an optical reading device are moved relative to each other in a reciprocal manner to derive a read-out signal both in forward and backward movements, the polarity of the read-out signal is selectively inverted in accordance with the mutual relation between the write-in direction and the read-out direction, the read-out signal is converted into a bivalent signal, and a reproduced signal is derived from the bivalent signal in such a manner that front or rear edges of pits viewed in the write-in direction are always detected.
Inventors
- 👤 Takao Rokutan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 04:18
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/002; G11B7/0033; G11B7/004; G11B7/005
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
76 words
A method for reproducing data recorded on an optical card on which said data has been recorded by modulating distances between successive pits comprising the steps of: moving the optical card and an optical reading device relative to each other in a reciprocal manner to derive a read-out signal; and processing said read-out signal to derive a reproduced signal by detecting distances between front or rear edges of pits viewed in a write-in direction of pits.
Claim 2
Independent Claim
76 words
A method for reproducing data recorded on an optical card on which said data has been recorded by modulating distances between successive pits comprising the steps of: moving the optical card and an optical reading device relative to each other in a reciprocal manner to derive a read-out signal; and processing said read-out signal to derive a reproduced signal by detecting distances between front or rear edges of pits viewed in a write-in direction of pits.
Claim 3
Dependent Claim
26 words
A method according to claim 1, wherein the reproduced signal is derived by detecting distances between the front edges of pits viewed in the write-in direction.
Claim 4
Dependent Claim
25 words
A method according to claim 1, wherein said reproduced signal is derived by detecting distances between rear edges of pits viewed in the write-in direction.
Claim 5
Dependent Claim
36 words
A method according to claim 1, wherein a read-out direction and the write-in direction are compared to derive a condition signal, and the polarity of the read-out signal is changed in accordance with said condition signal.
Claim 6
Dependent Claim
26 words
A method according to claim 4, wherein said write-in direction is detected by reading-out a write-in direction flag recorded at both ends of respective data blocks.
Claim 7
Dependent Claim
92 words
A method according to claim 4, wherein the read-out signal is converted into a bivalent signal, a read-out direction signal and a write-in direction signal are supplied to a first exclusive OR circuit whose output signal is supplied to a second exclusive OR circuit together with the bivalent signal, an output of the second exclusive OR circuit is supplied to a clock input terminal of a D-flip-flop whose Q output terminal is connected to a D input terminal, and the reproduced signal is derived from a Q output terminal of the D-flip-flop.
Claim 8
Dependent Claim
118 words
A method according to claim 4, wherein the read-out signal is supplied to a differential circuit to derive a differential signal, a read-out direction signal and a write-in direction signal are supplied to an exclusive OR circuit whose output is supplied as a control signal to a polarity switching circuit to which is supplied said differential signal to derive an inverted or non-inverted differential signal which is supplied to a bivalent circuit to derive a bivalent signal, said bivalent signal is supplied to a clock input terminal of a D-flip-flop whose Q output terminal is connected to a D input terminal of the D-flip-flop, and said reproduced signal is derived from a Q output terminal of the D-flip-flop.
References Cited (Backward Citations)
US2916624A
Cited
US3619569A
Cited
US4650979A
Cited
US4525822A
Cited
US4558441A
Cited
US4599717A
Cited
EP0156555A1
Cited
US4740675A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-01-10 | 1992-07-11 | 1993-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-10 | 1996-07-11 | 1997-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-10 | 2000-07-11 | 2001-01-10 | $7700.00 | Window Closed / Lapsed |