US4963998A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for marking a recorded signal
Assignee: EMI Group Ltd
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Filing: 1989-04-20
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Granted: 1990-10-16
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Expires: 2009-04-20
Abstract
Abstract This invention relates to apparatus for marking a recorded signal. The apparatus includes means for generating and storing a marking signal comprising at least two codes which are mutually in phase quadrature. The codes are converted to analogue signal and are used to phase-shift modulate the signal to be recorded, the modulating means performing the function of a single side band modulator on the signal to be recorded.
Inventors
- 👤 Barry G. Maufe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:40
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/00086; G11B20/00884
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
83 words
Apparatus for marking a recorded signal, said apparatus including: means for generating and storing a marking signal comprising at least two codes which are mutually in phase quadrature; means for converting said codes from a digital to an analogue signal; and modulating means including phase shift means such that the two marking codes can be used to phase-shift modulate the signal to be recorded, said modulating means performing the function of a single side band modulator on the said signal to be recorded.
Claim 2
Dependent Claim
83 words
Apparatus for marking a recorded signal, said apparatus including: means for generating and storing a marking signal comprising at least two codes which are mutually in phase quadrature; means for converting said codes from a digital to an analogue signal; and modulating means including phase shift means such that the two marking codes can be used to phase-shift modulate the signal to be recorded, said modulating means performing the function of a single side band modulator on the said signal to be recorded.
Claim 3
Dependent Claim
49 words
Apparatus as claimed in claim 1, said apparatus for marking the recorded signal including: means for generating a marking signal, said signal comprising a sequence of binary elements; and means for translating each like binary element of said sequence into a randomised sequence of binary elements prior to modulation.
Claim 4
Dependent Claim
46 words
Apparatus as claimed in claim 1, said apparatus including: means for demodulating said modulated signal; means for digitising said demodulated signal into a sequence; and means for correlating said demodulated, digitised sequence with reference sequences stored in the means for generating and storing the marking signal.
References Cited (Backward Citations)
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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) | 1993-10-15 | 1994-04-16 | 1994-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-15 | 1998-04-16 | 1998-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-15 | 2002-04-16 | 2002-10-16 | $7700.00 | Window Closed / Lapsed |