US3920900A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telecommunications receivers
Assignee: Post Office
•
Filing: 1974-08-28
•
Granted: 1975-11-18
•
Expires: 1994-08-28
Abstract
Abstract A method and apparatus are described for reframing a framestructured telecommunication signal in which detection of a suspected misframe condition initiates a checking process to determine whether a misframe condition exists and at the same time initiates a hunting process to determine the correct frame structure. Checking is effected by accumulating indications of in frame and out of frame conditions in a bidirectional counter and an out of frame decision is made when the counter reaches a limit value. A local frame distributor is then shifted immediately to the new frame structure found by the hunting process. Reframing is thereby accomplished with minimal information loss.
Inventors
- 👤 Laurence Keith Fineman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:28
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/02; H04J3/06
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
211 words
Apparatus for reframing a frame structured communication signal comprising: signal detecting and generating means connected to receive a frame structured communication signal for generating line frame synchronization signals in response to the detection of frame synchronization patterns in said frame structured communication signal; main local frame structure generating means for generating main local frame timing signals for receiving and decoding said frame structured communication signal; reserve local frame structure generating means for generating reserve local frame timing signals, said reserve local frame structure generating means being connected to be reset by each occurrence of said line frame synchronization signals; decision means; first and second persistence check means respectively coupled to said decision means, said first persistence check means operable in response to persistent non-coincidence of line frame synchronization signals and main local frame timing signals to deliver a first output to said decision means and said second persistence check means operable in response to the persistent coincidence of reserve local frame timing signals and line frame sychronization signals to deliver a second output to said decision means, said decision means being operable in response to receipt of said first and second outputs simultaneously to reset said main local frame structure generating means in alignment with the reserve local frame timing signal.
Claim 2
Dependent Claim
211 words
Apparatus for reframing a frame structured communication signal comprising: signal detecting and generating means connected to receive a frame structured communication signal for generating line frame synchronization signals in response to the detection of frame synchronization patterns in said frame structured communication signal; main local frame structure generating means for generating main local frame timing signals for receiving and decoding said frame structured communication signal; reserve local frame structure generating means for generating reserve local frame timing signals, said reserve local frame structure generating means being connected to be reset by each occurrence of said line frame synchronization signals; decision means; first and second persistence check means respectively coupled to said decision means, said first persistence check means operable in response to persistent non-coincidence of line frame synchronization signals and main local frame timing signals to deliver a first output to said decision means and said second persistence check means operable in response to the persistent coincidence of reserve local frame timing signals and line frame sychronization signals to deliver a second output to said decision means, said decision means being operable in response to receipt of said first and second outputs simultaneously to reset said main local frame structure generating means in alignment with the reserve local frame timing signal.
Claim 3
Dependent Claim
111 words
Apparatus as claimed in claim 1 in which said first persistence check means includes a bi-directional counter having lower and upper limits, the stored count being changed in a first sense in response to non-coincidence of a line frame synchronization signal and a main local frame timing signal and being changed in a second sense, opposite to the first sense, in response to coincidence of a line frame synchronization signal and a main local frame timing signal, a said first output being delivered to said decision means when said counter reaches one of said limits in response to said non-coincidences of line frame synchronization signals and main local frame timing signals.
Claim 4
Dependent Claim
74 words
Apparatus as claimed in claim 1 in which said second persistence check means comprises a scale-of-three counter which counts one in response to a coincidence of a reserve local frame timing signal and a line frame synchronization signal and is reset by non-coincidence of a reserve local frame timing signal and a line frame synchronization signal, a said second output being delivered to said decision means when said counter reaches a count of three.
Claim 5
Dependent Claim
86 words
Apparatus as claimed in claim 2 in which said bi-directional counter has lower and upper limits of 0 and 9 respectively, the stored count being increased by three in response to a non-coincidence of a line frame synchronization signal and a main local frame timing signal and being decreased by one in response to coincidence of a line frame synchronization signal and a main local frame timing signal, a said first output being delivered to said decision Means when said counter reaches a count of 9.
Claim 6
Independent Claim
125 words
A method of re-framing a frame structured communication signal comprising the steps of: generating line frame synchronization signals in response to the detection of a frame synchronization pattern in said frame structured communication signal; generating main local frame timing signals for receiving and decoding said frame structured communication signal; generating reserve local frame timing signals, said reserve local frame time signals being reset by each occurrence of said line frame synchronization signals; resetting said main local frame time signals in alignment with said reserve local frame time signals on detecting the joint occurrence of persistent non-coincidence of said line frame synchronization signals and said main local frame time signals and persistence coincidence of said line frame synchronization signals and said reserve local frame time signals.
Claim 7
Independent Claim
125 words
A method of re-framing a frame structured communication signal comprising the steps of: generating line frame synchronization signals in response to the detection of a frame synchronization pattern in said frame structured communication signal; generating main local frame timing signals for receiving and decoding said frame structured communication signal; generating reserve local frame timing signals, said reserve local frame time signals being reset by each occurrence of said line frame synchronization signals; resetting said main local frame time signals in alignment with said reserve local frame time signals on detecting the joint occurrence of persistent non-coincidence of said line frame synchronization signals and said main local frame time signals and persistence coincidence of said line frame synchronization signals and said reserve local frame time signals.
Claim 8
Dependent Claim
52 words
A method of reframing a frame structured communication signal as claimed in claim 5 in which detection of coincidence of said line frame synchronization signals and said reserve local frame timing signals is performed by detecting three successive coincidences of said line frame synchronization signals and said reserve local frame timing signals.
Claim 9
Dependent Claim
110 words
A method of reframing a frame structured communication signal as claimed in claim 5 in which detection of persistent non-coincidence of said line frame synchronization signals and said main local frame timing signals is performed by detecting the occurrence of an accumulated weight of nine in a counter whose stored count is increased by three on occurrence of a non-coincidence of a line frame synchronization signal and a main local frame timing signal and reduced by one on occurrence of a coincidence of a line frame synchronization signal and a main local frame timing signal, the stored count having a lower limit of zero and an upper limit of nine.
References Cited (Backward Citations)
US3525813A
Cited
US3581010A
Cited
US3735045A
Cited
US3770897A
Cited
US3887769A
Cited
US3854011A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |