US4876682A
Expired / Lapsed
US
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Switching tdm digital signals
Assignee: Nortel Networks Ltd
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Filing: 1986-05-13
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Granted: 1989-10-24
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Expires: 2006-05-13
Abstract
Abstract Digital signals are multiplexed in tdm (time division multiplex) frames each consisting of an integral number of sub-frames each consisting of an integral number of sub-sub-frames, whereby the tdm frame, sub-frame, and sub-sub-frame periods are harmonically related. The signals are switched in a hierarchy of time switches which are operated sequentially and cyclically with frame periods corresponding to respective ones of these harmonically related periods, whereby the switches switch services at respective harmonically related bandwidths. The harmonic tdm frame structure and the hierarchical switch arrangement combine to facilitate the switching of many services with various bandwidths using relatively small switches.
Inventors
- 👤 Alan F. Graves
- 👤 Paul A. Littlewood
- 👤 Johannes S. Weiss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:52
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/08; H04J; H04J3/00; H04J3/02; H04J3/08; H04J3/16; H04J3/1605; H04J3/1611
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
110 words
A method of switching digital signals multiplexed in tdm (time division multiplex) frames having harmonically related frame and sub-frame periods, comprising the steps of cyclically operating a first time switch with a frame period corresponding to one of said harmonically related periods thereby to switch time channels of said digital signals to provide switched signals having a first bandwidth; cyclically operating a second time switch with a frame period corresponding to another of said harmonically related periods thereby to switch time channels of said digital signals to provide switched signals having a second bandwidth harmonically related to the first bandwidth; and conducting digital signals to, from, and between the switches.
Claim 2
Independent Claim
110 words
A method of switching digital signals multiplexed in tdm (time division multiplex) frames having harmonically related frame and sub-frame periods, comprising the steps of cyclically operating a first time switch with a frame period corresponding to one of said harmonically related periods thereby to switch time channels of said digital signals to provide switched signals having a first bandwidth; cyclically operating a second time switch with a frame period corresponding to another of said harmonically related periods thereby to switch time channels of said digital signals to provide switched signals having a second bandwidth harmonically related to the first bandwidth; and conducting digital signals to, from, and between the switches.
Claim 3
Dependent Claim
91 words
A method as claimed in claim 1 of switching digital signals multiplexed in tdm frames having harmonically related frame, sub-frame, and sub-sub-frame periods, further comprising the steps of cyclically operating a third time switch with a frame period corresponding to a further one of said harmonically related periods thereby to switch time channels of said digital signals to provide switched signals having a third bandwidth harmonically related to the first and second bandwidths; and conducting digital signals between the third switch and at least one of the first and second switches.
Claim 4
Dependent Claim
21 words
A method as claimed in claim 1 wherein one of the switches is operated with a frame period of 125 microseconds.
Claim 5
Dependent Claim
21 words
A method as claimed in claim 1 wherein one of the switches is operated with a frame period of 5 microseconds.
Claim 6
Dependent Claim
21 words
A method as claimed in claim 1 wherein one of the switches is operated with a frame period of 5/32 microseconds.
Claim 7
Dependent Claim
21 words
A method as claimed in claim 2 wherein one of the switches is operated with a frame period of 125 microseconds.
Claim 8
Dependent Claim
21 words
A method as claimed in claim 2 wherein one of the switches is operated with a frame period of 5 microseconds.
Claim 9
Dependent Claim
21 words
A method as claimed in claim 2 wherein one of the switches is operated with a frame period of 5/32 microseconds.
Claim 10
Dependent Claim
71 words
Apparatus for switching digital signals multiplexed in tdm (time division multiplex) frames having a plurality of harmonically related frame and sub-frame periods, the apparatus comprising: first and second time switches; means for coupling digital signals to, from, and between the time switches; and means for operating the time switches with different frame periods corresponding to respective ones of said harmonically related Periods thereby to switch the digital signals with different bandwidths.
Claim 11
Dependent Claim
71 words
Apparatus for switching digital signals multiplexed in tdm (time division multiplex) frames having a plurality of harmonically related frame and sub-frame periods, the apparatus comprising: first and second time switches; means for coupling digital signals to, from, and between the time switches; and means for operating the time switches with different frame periods corresponding to respective ones of said harmonically related Periods thereby to switch the digital signals with different bandwidths.
Claim 12
Dependent Claim
70 words
Apparatus as claimed in claim 9 and further comprising: a third time switch; means for coupling digital signals between the third time switch and at least one of the first and second time switches; and means for operating the third time switch with a further different frame period corresponding to a further respective one of said harmonically related periods thereby to switch the digital signals with a further different bandwidth.
Claim 13
Dependent Claim
27 words
Apparatus as claimed in claim 9 wherein the means for operating is arranged for operating the switches with frame periods selected from 125 microseconds and sub-multiples thereof.
Claim 14
Dependent Claim
19 words
Apparatus as claimed in claim 9 wherein at least one of the time switches comprises a matrixed time switch.
Claim 15
Dependent Claim
19 words
Apparatus as claimed in claim 9 wherein at least one of the time switches comprises a commutated time switch.
Claim 16
Dependent Claim
27 words
Apparatus as claimed in claim 10 wherein the means for operating is arranged for operating the switches with frame periods selected from 125 microseconds and sub-multiples thereof.
Claim 17
Dependent Claim
19 words
Apparatus as claimed in claim 10 wherein at least one of the time switches comprises a matrixed time switch.
Claim 18
Dependent Claim
19 words
Apparatus as claimed in claim 10 wherein at least one of the time switches comprises a commutated time switch.
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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) | 1992-10-23 | 1993-04-24 | 1993-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-23 | 1997-04-24 | 1997-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-23 | 2001-04-24 | 2001-10-24 | $7700.00 | Window Closed / Lapsed |