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US4549288A
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Apparatus for enhancing the playback signal in an optical data recording system
Assignee: NORTH AMERCAN PHILIPS Corp
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Filing: 1982-12-20
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Granted: 1985-10-22
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Expires: 2002-12-20
Abstract
Abstract Optical data recording apparatus which enhances a playback signal by comparing the lengths of the lands on a recording medium with the lengths of the pits on it and changes the playback signal to represent equality between such lengths.
Inventors
- 👤 Albert Y. Chan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:56
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/005
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
139 words
Apparatus for enhancing the playback signal in an optical recording system in which a read beam impinges on a record carrier having data stored on it in the form of pits and lands, said system producing in response to said read beam impinging on said pits and lands a signal which alternates in accordance therewith; said apparatus including clipping means clipping said alternating signal to produce signal pulses representative of said lands and pits; pulse converting means converting said signal pulses into two sawtooth waves, one having amplitudes representing the lengths of said pits, the other having amplitudes representing the lengths of said lands; comparator means comparing said one sawtooth wave with said other and producing an error signal; and feedback means using said error signal to improve said alternating signal so that it represents said data more accurately.
Claim 2
Dependent Claim
139 words
Apparatus for enhancing the playback signal in an optical recording system in which a read beam impinges on a record carrier having data stored on it in the form of pits and lands, said system producing in response to said read beam impinging on said pits and lands a signal which alternates in accordance therewith; said apparatus including clipping means clipping said alternating signal to produce signal pulses representative of said lands and pits; pulse converting means converting said signal pulses into two sawtooth waves, one having amplitudes representing the lengths of said pits, the other having amplitudes representing the lengths of said lands; comparator means comparing said one sawtooth wave with said other and producing an error signal; and feedback means using said error signal to improve said alternating signal so that it represents said data more accurately.
Claim 3
Dependent Claim
61 words
Apparatus according to claim 1, wherein said comparator means includes a separate peak detector circuit for each sawtooth wave, each peak detector circuit operating in response to its individual sawtooth wave and producing a signal representing an average thereof and said comparator means including a differential amplifier receiving each of said average signals and producing said error signal in response thereto.
Claim 4
Dependent Claim
34 words
Apparatus according to claim 2, wherein said pulses converting means includes a separate integrating circuit for each of said signal pulses, each of said integrating circuits producing a different one of said sawtooth waves.
Claim 5
Dependent Claim
39 words
Apparatus according to claim 3, wherein said pulse converting means includes an inverter connected to the input of the integrating circuit producing the sawtooth wave associated with said lands, said inverter receiving said signal pulses from said clipping means.
Claim 6
Dependent Claim
25 words
Apparatus according to claim 4, wherein said feedback means includes an integrator receiving said error signal and applying its integrated output to said clipping means.
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) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |