Patent US4615025A successfully refreshed from Google Patents.
US4615025A
Expired / Lapsed
US
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Data transmission system
Assignee: US Philips Corp
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Filing: 1984-08-07
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Granted: 1986-09-30
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Expires: 2004-08-07
Abstract
Abstract A data transmission system using a transmission code in which one data state corresponds to a zero transmission level, such as the alternate mark inversion (AMI) code, includes at each terminal adaptive signal processing circuits such as an echo canceller (402) and/or an adaptive equalizer (409). Each terminal includes a decision circuit (408) an output of which controls a switch (410) which is operative to allow updating of the adaption of the echo canceller (402) and adaptive equalizer (409) only when a data state corresponding to a zero transmission level is detected.
Inventors
- 👤 Michael G. Vry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:55
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04B; H04B3/00; H04B3/02; H04B3/20; H04B3/23; H04B3/235
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
107 words
A transmission system for digital data signals and which employs a transmission code in which one data state of such signals corresponds to a zero transmission level, comprising: an adaptive signal processing circuit which adapts to changes in the transmission characteristics of the system and updates such adaptation at fixed intervals; means for detecting the data states represented by received data signals; and means connected to said signal processing circuit and to said detecting means for inhibiting the updating of the adaptation of said signal processing circuit during intervals in which the transmission level of a received data signal does not correspond to said one data state.
Claim 2
Dependent Claim
107 words
A transmission system for digital data signals and which employs a transmission code in which one data state of such signals corresponds to a zero transmission level, comprising: an adaptive signal processing circuit which adapts to changes in the transmission characteristics of the system and updates such adaptation at fixed intervals; means for detecting the data states represented by received data signals; and means connected to said signal processing circuit and to said detecting means for inhibiting the updating of the adaptation of said signal processing circuit during intervals in which the transmission level of a received data signal does not correspond to said one data state.
Claim 3
Dependent Claim
21 words
A digital data transmission system as claimed in claim 1, in which the transmission code is the Alternate Mark Inversion code.
Claim 4
Dependent Claim
22 words
A transmission system as claimed in claim 1 or claim 2, in which the adaptive signal processing circuit comprises an adaptive equaliser.
Claim 5
Dependent Claim
51 words
A transmission system as claimed in any one of claims 1, 2, and 3, said system being a duplex transmission system, in which the adaptive signal processing circuit comprises an echo canceller, and further comprising means for disabling said inhibiting means for an initial period of transmission of a data signal.
Claim 6
Dependent Claim
70 words
A transmission system as claimed in claim 4, in which said means for detecting the data states of received data signals is a decision circuit, and said disabling means comprises circuit means for detecting correlation between a transmitted data signal and a received data signal detected by the decision circuit, said disabling means being adapted to produce a disabling signal for disabling said inhibiting means when such correlation is detected.
Claim 7
Independent Claim
112 words
A method whereby the adaptation of a signal processing circuit to the transmission characteristics of a transmission system for digital data signals is updated at fixed intervals, comprising: encoding the signals into a transmission code in which one of the data states thereof corresponds to a zero transmission level; updating the adaptation of the signal processing circuit at fixed intervals to adapt to changes in the transmission characteristics of the system; detecting the data states represented by received data signals; and inhibiting the updating of the adaptation of the signal processing circuit during intervals in which the transmission level of a received data signal does not correspond to said one data state.
Claim 8
Independent Claim
112 words
A method whereby the adaptation of a signal processing circuit to the transmission characteristics of a transmission system for digital data signals is updated at fixed intervals, comprising: encoding the signals into a transmission code in which one of the data states thereof corresponds to a zero transmission level; updating the adaptation of the signal processing circuit at fixed intervals to adapt to changes in the transmission characteristics of the system; detecting the data states represented by received data signals; and inhibiting the updating of the adaptation of the signal processing circuit during intervals in which the transmission level of a received data signal does not correspond to said one data state.
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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) | 1989-09-29 | 1990-03-31 | 1990-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-29 | 1994-03-31 | 1994-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-29 | 1998-03-31 | 1998-09-30 | $7700.00 | Window Closed / Lapsed |