US4977593A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical communications network
Assignee: British Telecommunications PLC
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Filing: 1988-11-28
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Granted: 1990-12-11
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Expires: 2008-11-28
Abstract
Abstract A central station (4) for a digital communications network comprising a plurality of outstations (8) and a branch network of waveguides comprising a single waveguide (6) from the central station, one or more passive splitters (1) and two or more secondary waveguides (14) for onward transmission to the outstations: the central station comprising; means for transmitting data to outstations in the form of a stream of frames, each comprising a synchronisation signal in the form of a predetermined pattern of bits; scrambling means for scrambling the frames in accordance with a predetermined binary sequence; and means for detecting in data received from the outstations the presence of the scrambled synchronisation signal thereby obtaining information concerning reflections in the branch network.
Inventors
- 👤 John W. Ballance
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:59
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/02; H04J3/06; H04J3/0635; H04J3/0682; H04B; H04B10/00; H04B10/27; H04B10/272; H04B10/50; H04J14/00; H04J14/08; H04J3/0602; H04J3/0605; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03828; H04L25/03866
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
136 words
A central station for a digital communications network comprising a plurality of outstations and a branch network of waveguides comprising a single waveguide from the central station, one or more passive splitters and two or more secondary waveguides for bidirectional transmission to and from the outstations: the central station comprising transmitting means for transmitting data to outstations in the form of a stream of frames, each comprising a synchronisation signal in the form of a predetermined pattern of bits; and characterised by scrambling means for scrambling the synchronisation signal and at least some of the data bits of each of the frames in accordance with a predetermined binary sequence; and by means for detecting in data received from the outstations the presence of the scrambled synchronisation signal thereby obtaining information concerning reflections in the branch network.
Claim 2
Dependent Claim
136 words
A central station for a digital communications network comprising a plurality of outstations and a branch network of waveguides comprising a single waveguide from the central station, one or more passive splitters and two or more secondary waveguides for bidirectional transmission to and from the outstations: the central station comprising transmitting means for transmitting data to outstations in the form of a stream of frames, each comprising a synchronisation signal in the form of a predetermined pattern of bits; and characterised by scrambling means for scrambling the synchronisation signal and at least some of the data bits of each of the frames in accordance with a predetermined binary sequence; and by means for detecting in data received from the outstations the presence of the scrambled synchronisation signal thereby obtaining information concerning reflections in the branch network.
Claim 3
Dependent Claim
54 words
A central station as claimed in claim 1 wherein each frame comprises a first portion comprising the synchronisation signal, and a second portion comprising traffic data, and wherein the scrambling means is arranged to scramble the first portion with said predetermined binary sequence, and to scramble the second portion with another predetermined binary sequence.
Claim 4
Dependent Claim
22 words
A central station as claimed in either claim 1 wherein the or each predetermined binary sequence is a pseudo random binary sequence.
Claim 5
Dependent Claim
18 words
A central station as claimed in claim 1 wherein said predetermined pattern is a sequence of zero bits.
Claim 6
Dependent Claim
15 words
A central station as claimed in claim 1 wherein the detecting means comprises an autocorrelator.
Claim 7
Dependent Claim
50 words
A digital communications network comprising a central station as claimed in claim 1, a plurality of outstations and a branch network of waveguides comprising a single waveguide from the central station, one or more passive splitters and two or more secondary waveguides for bidirectional transmission to and from the outstations.
References Cited (Backward Citations)
FR2550400A1
Cited
US4817144A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-10 | 1994-06-11 | 1994-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-10 | 1998-06-11 | 1998-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-10 | 2002-06-11 | 2002-12-11 | $7700.00 | Window Closed / Lapsed |