US4438520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for regenerating a data word on a communications ring
Assignee: Massachusetts Institute of Technology
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Filing: 1981-07-22
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Granted: 1984-03-20
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Expires: 2001-07-22
Abstract
Abstract A system for regenerating an n-bit data word on a token mediated communications ring includes a decoder for receiving the data signal from the ring and deriving the n-bit data word and an associated clock signal from the received data signal. A re-transmit clock generator generates a transmit clock signal incorporating the i th through the n th cycles from the derived clock signal, followed by i cycles at the nominal system clock rate. A delay network delays the derived data word by a period approximately equal to the period of the nominal system clock. An encoding network regenerates the n-bit data word for re-transmission on the ring by encoding the delayed derived data word with the transmit clock signal.
Inventors
- 👤 Jerome H. Saltzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:48
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/20; H04L25/24; H04L25/242; H04L12/00; H04L12/28; H04L12/42; H04L12/422
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
219 words
A system for regenerating a n-bit data word on a communications ring signal path, said system having a nominal system clock rate, comprising: A. means for receiving said n-bit data word and generating an n-cycle derived clock signal and an n-bit derived data word from said received data word, B. means for generating a local data word from said derived data word, said local data word corresponding to said derived data word delayed by i periods, each of said periods being approximately equal to the period associated with the nominal system clock rate, C. means for generating an n-cycle transmit clock signal from said derived clock signal, said transmit clock signal including n-i cycles at the same rate as the (i+1) th through the n th cycles of said derived clock signal followed by i cycles at said system clock rate, where i is greater than or equal to one, and less than or equal to n-1, D. means for generating an n-bit transmit data word from said transmit clock signal and said local data word, each bit corresponding in time to a correspondingly positioned cycle of said transmit clock signal and having a bit value corresponding to the correspondingly positioned bit value of said local data word, wherein said transmit data word is said reclocked n-bit data word.
Claim 2
Independent Claim
219 words
A system for regenerating a n-bit data word on a communications ring signal path, said system having a nominal system clock rate, comprising: A. means for receiving said n-bit data word and generating an n-cycle derived clock signal and an n-bit derived data word from said received data word, B. means for generating a local data word from said derived data word, said local data word corresponding to said derived data word delayed by i periods, each of said periods being approximately equal to the period associated with the nominal system clock rate, C. means for generating an n-cycle transmit clock signal from said derived clock signal, said transmit clock signal including n-i cycles at the same rate as the (i+1) th through the n th cycles of said derived clock signal followed by i cycles at said system clock rate, where i is greater than or equal to one, and less than or equal to n-1, D. means for generating an n-bit transmit data word from said transmit clock signal and said local data word, each bit corresponding in time to a correspondingly positioned cycle of said transmit clock signal and having a bit value corresponding to the correspondingly positioned bit value of said local data word, wherein said transmit data word is said reclocked n-bit data word.
Claim 3
Dependent Claim
28 words
A system according to claim 1 wherein each of said i periods is substantially equal to the period of the first clock cycle of said derived clock signal.
Claim 4
Dependent Claim
25 words
A system according to claim 1 wherein each of said i periods is substantially equal to the period associated with said nominal system clock rate.
Claim 5
Dependent Claim
48 words
A system according to claim 1 wherein each of said i periods is substantially equal to T where (T o +a)<T<(T o +b), where T o is the period associated with said nominal system clock rate and a and b are values related to the system noise level.
Claim 6
Independent Claim
14 words
A system according to claims 1 or 2 or 3 or 4 wherein i=1.
References Cited (Backward Citations)
US3113268A
Cited
US3737585A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |