US3825682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Balanced line driver, line receiver system
Assignee: RCA Corp
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Filing: 1973-06-27
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Granted: 1974-07-23
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Expires: 1993-06-27
Abstract
Abstract The problem dealt with here is that of preventing erratic behavior of a line receiver when an open occurs in the balanced transmission line feeding the receiver, or when the power supply for the line driver goes off. In the present circuit, bias currents are applied to the transmission line in such a way that the potentials due to these currents are the same on both conductors of the line. A resistor network, responsive to the interruption in bias current flow through one or both conductors or to a change in the path taken by such current flow, places the input circuit of the receiver at a voltage indicative of a given binary value.
Inventors
- 👤 P Phillips
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:51
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/08; H04B; H04B3/00; H04B3/02; H04B3/46
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
105 words
In combination: a differential line driver having a pair of output terminals; a differential line receiver having a pair of input terminals; a two conductor transmission line connecting the output terminals of said line driver to the input terminals of said line receiver; means for quiescently establishing a continuous flow of bias current through each conductor while maintaining both conductors at substantially the same bias potential; and means responsive to a change in the path taken by either bias current, for establishing a difference in potential between said input terminals of said line receiver of a given sense and of greater than a given amplitude.
Claim 2
Dependent Claim
105 words
In combination: a differential line driver having a pair of output terminals; a differential line receiver having a pair of input terminals; a two conductor transmission line connecting the output terminals of said line driver to the input terminals of said line receiver; means for quiescently establishing a continuous flow of bias current through each conductor while maintaining both conductors at substantially the same bias potential; and means responsive to a change in the path taken by either bias current, for establishing a difference in potential between said input terminals of said line receiver of a given sense and of greater than a given amplitude.
Claim 3
Dependent Claim
89 words
In the combination as set forth in claim 1, said means for establishing a continuous flow of bias current comprising means for applying a current to one end of one of the conductors and withdrawing that current from the other end of said one conductor and means for applying a current of the same value to one end of the other of said conductors and withdrawing it from the opposite end of said other conductors, said two currents being applied to flow in opposite directions through said two conductors.
Claim 4
Dependent Claim
46 words
In the combination as set forth in claim 1, said means responsive to a change in the path taken by either bias current, comprising load means connecting the end of said two conductors at said input terminals of said receiver to a point of reference potential.
Claim 5
Dependent Claim
173 words
In combination: a differential line driver having a pair of output terminals; a differential line receiver having a pair of input terminals; a two conductor transmission line connecting the output terminals of said line driver to the input terminals of said line receiver; means for quiescently establishing a continuous flow of bias current through each conductor while maintaining both conductors at substantially the same bias pOtential; a pair of current paths, one connected between the receiver end of one conductor and a point at said bias potential and the other connected between the receiver end of the other conductor and said point at said bias potential, whereby if either conductor opens, bias current formerly flowing through that conductor flows instead through the current path connected to the receiver end of that conductor; and means responsive to a flow of bias current through one or both of said paths for establishing a difference in potential between said input terminals of said line receiver of a given sense and of greater than a given amplitude.
Claim 6
Dependent Claim
173 words
In combination: a differential line driver having a pair of output terminals; a differential line receiver having a pair of input terminals; a two conductor transmission line connecting the output terminals of said line driver to the input terminals of said line receiver; means for quiescently establishing a continuous flow of bias current through each conductor while maintaining both conductors at substantially the same bias pOtential; a pair of current paths, one connected between the receiver end of one conductor and a point at said bias potential and the other connected between the receiver end of the other conductor and said point at said bias potential, whereby if either conductor opens, bias current formerly flowing through that conductor flows instead through the current path connected to the receiver end of that conductor; and means responsive to a flow of bias current through one or both of said paths for establishing a difference in potential between said input terminals of said line receiver of a given sense and of greater than a given amplitude.
Claim 7
Dependent Claim
104 words
In the combination as set forth in claim 4, said means for establishing a continuous flow of bias current comprising a current source connected to the driver end of one conductor and a current sink connected to the driver end of the other conductor, and a current sink connected to the receiver end of said one conductor and a current source connected to the receiver end of said other conductor, whereby if one or both of said current source and current sink at the receiver end of said two conductors should turn off, bias current would flow through one or both of said paths.
Claim 8
Dependent Claim
24 words
In the combination as set forth in claim 5, said means responsive to a flow of bias current comprising resistive means in each path.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |