US3761842A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Twisted pair flat conductor cable with means to equalize impedance and propagation velocity
Assignee: AT&T Inc
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Filing: 1972-06-01
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Granted: 1973-09-25
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Expires: 1992-06-01
Abstract
Abstract The use of so-called paired flat cable in interconnection work is attractive because of mass termination and rearrangement cost benefits. Flat cable has been supplied with differing twist lengths to meet crosstalk problems, but present such designs also exhibit an unacceptable difference from pair to pair of characteristic impedance and propagation velocity. The present invention eliminates these differences by recognizing that the capacitance at each crossover point of a twisted pair can be controlled by making a crossover smaller in area for pairs with shorter twist lengths and larger for those with longer twist lengths. The capacitance per unit length and, by the same mechanism, the impedance and propagation velocities are thus equalized among the pairs of the flat cable.
Inventors
- 👤 Gandrud W Bentley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:50
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/02; H05K1/0213; H05K1/0216; H05K1/0228; H01; H01B; H01B11/00; H01B7/00; H01B7/08; H04; H04B; H04B3/00; H04B3/02; H04B3/32; H05K1/0237; H05K1/0245; H05K1/11; H05K1/118; H05K2201/00; H05K2201/09; H05K2201/09209; H05K2201/09218; H05K2201/09263; H05K2201/09654; H05K2201/097; Y; Y10; Y10S; Y10S439/00; Y10S439/941
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
135 words
In a communications cable comprising a plurality of pairs of conductive paths, unitary insulative means for holding the paths of each said pair in closely spaced juxtaposition, said pair paths undergoing juxtaposition reversals of differing periodicity from pair to pair, each such reversal occasioning a crossover of said pair paths and the distance between said crossovers along a given said pair constituting the twist length of said pair, a method for equalizing the characteristic impedance and propagation velocity for all said pairs in said cable comprising the steps of: reducing the width of each conductive path at each crossover region by a factor of substantially square root X for each reduction of a factor of X of said twist length, where the pair with the largest said twist length is taken as the reference pair.
Claim 2
Dependent Claim
135 words
In a communications cable comprising a plurality of pairs of conductive paths, unitary insulative means for holding the paths of each said pair in closely spaced juxtaposition, said pair paths undergoing juxtaposition reversals of differing periodicity from pair to pair, each such reversal occasioning a crossover of said pair paths and the distance between said crossovers along a given said pair constituting the twist length of said pair, a method for equalizing the characteristic impedance and propagation velocity for all said pairs in said cable comprising the steps of: reducing the width of each conductive path at each crossover region by a factor of substantially square root X for each reduction of a factor of X of said twist length, where the pair with the largest said twist length is taken as the reference pair.
Claim 3
Dependent Claim
53 words
The communications cable of claim 1, wherein all said pair paths are constructed with substantially the same standard width and wherein said crossover regions of all pairs but one are constructed with a path width less than said standard width by an amount dependent on the juxtaposition reversal periodicity of the given pair.
Claim 4
Dependent Claim
58 words
The communications cable of claim 1, wherein all said path pairs are constructed with substantially the same standard width and wherein said juxtaposition reversals are effected by crossover legs held at said standard width up to a point approaching the crossover and whereupon said path width is abruptly reduced to a prescribed lower value in the crossover zone.
Claim 5
Dependent Claim
22 words
A method pursuant to claim 1 comprising the further step of keeping the crossover region path width of said reference pair unchanged.
Claim 6
Dependent Claim
9 words
A method persuant to claim 4, wherein X 2.
Claim 7
Dependent Claim
126 words
A flat flexible cable comprising a plurality of pairs of conductive paths held in side-by-side relation in a medium, the paths of each pair undergoing crossover points at intervals different from pair-to-pair, each pair in said cable exhibiting the same properties of characteristic impedance and propagation velocity, characterized in that: the area common to each crossover point of each path is controlled to result in the same crossover capacitance for each pair for a given long length of medium by reducing the width of each conductive path at each crossover region by a factor of substantially Square Root X for each reduction of a factor of X of said twist length, where the pair with the largest said twist length is taken as the reference pair.
Claim 8
Dependent Claim
126 words
A flat flexible cable comprising a plurality of pairs of conductive paths held in side-by-side relation in a medium, the paths of each pair undergoing crossover points at intervals different from pair-to-pair, each pair in said cable exhibiting the same properties of characteristic impedance and propagation velocity, characterized in that: the area common to each crossover point of each path is controlled to result in the same crossover capacitance for each pair for a given long length of medium by reducing the width of each conductive path at each crossover region by a factor of substantially Square Root X for each reduction of a factor of X of said twist length, where the pair with the largest said twist length is taken as the reference pair.
References Cited (Backward Citations)
US1792273A
Cited
US3104363A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |