US4554504A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Negative resistance compensated transformer
Assignee: Reliance Comm Tec Corp
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Filing: 1984-04-30
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Granted: 1985-11-19
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Expires: 2004-04-30
Abstract
Abstract A compensated circuit for use in interfacing a transmission device to a cable facility. The circuit includes a transformer one winding of which is connected to the cable facility and the other winding of which is connected through an impedance generating device to the transmission device. The circuit provides a predetermined one of a number of selectable impedances to the cable facility. The impedance generating device allows the desired impedance to be elected and includes a negative resistance generating circuit which responds to the current flowing in the loop formed by the winding and the impedance generating device.
Inventors
- 👤 Philip L. Dillon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:56
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/42
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
167 words
A compensated circuit for use in interfacing a transmission device to a cable facility comprising: (a) transformer means having first and second windings, said first winding being connected to said cable facility and said second winding having first and second terminals; and (b) impedance generating means connected between said second winding and said transmission device comprising: (i) first selectable switch means for selecting one of a predetermined number of resistances each of said resistances being associated with a selected one of a predetermined number of selectable impedances; and (ii) negative resistance generating means having an input and an output, said first selectable means being connected between said first terminal and said input, said output being connected to said second terminal to thereby form a loop, said negative resistance generating means being responsive to the current flowing in said loop for presenting a negative resistance at said second terminal such that said circuit provides to said cable facility said selected one of said predetermined number of selectable impedances.
Claim 2
Dependent Claim
167 words
A compensated circuit for use in interfacing a transmission device to a cable facility comprising: (a) transformer means having first and second windings, said first winding being connected to said cable facility and said second winding having first and second terminals; and (b) impedance generating means connected between said second winding and said transmission device comprising: (i) first selectable switch means for selecting one of a predetermined number of resistances each of said resistances being associated with a selected one of a predetermined number of selectable impedances; and (ii) negative resistance generating means having an input and an output, said first selectable means being connected between said first terminal and said input, said output being connected to said second terminal to thereby form a loop, said negative resistance generating means being responsive to the current flowing in said loop for presenting a negative resistance at said second terminal such that said circuit provides to said cable facility said selected one of said predetermined number of selectable impedances.
Claim 3
Dependent Claim
36 words
The circuit of claim 1 wherein said negative resistances generating means includes an adjustable value resistance means, the value of said negative resistance being constant and determined by the setting of said adjustable value resistance means.
Claim 4
Dependent Claim
59 words
The circuit of claim 1 wherein said negative resistance generating means includes a temperature compensated resistance means having a resistivity temperature coefficient selected to be opposite in phase to the resistivity temperature coefficient of said first and second windings such that said circuit provides said selected one of said predetermined number of selectable impedances independent of changes in temperature.
Claim 5
Dependent Claim
60 words
The circuit of claim 2 wherein said negative resistance generating means further includes a temperature compensated resistance means having a resistivity temperature coefficient selected to be opposite in phase to the resistivity temperature coefficient of said first and second windings such that said circuit provides said selected one of said predetermined number of selectable impedances independent of changes in temperature.
Claim 6
Dependent Claim
49 words
The circuit of claim 1 wherein said first selectable switch means includes first and second resistors connected in series between said first terminal and said negative resistance generating means input and first and second switch means connected in parallel across a respective one of said first and second resistors.
Claim 7
Dependent Claim
49 words
The circuit of claim 2 wherein said first selectable switch means include first and second resistors connected in series between said first terminal and said negative resistance generating means input and first and second switch means connected in parallel across a respective one of said first and second resistors.
Claim 8
Dependent Claim
49 words
The circuit of claim 3 wherein said first selectable switch means include first and second resistors connected in series between said first terminal and said negative resistance generating means input and first and second switch means connected in parallel across a respective one of said first and second resistors.
Claim 9
Dependent Claim
193 words
A compensated circuit for use in interfacing a transmission device to a cable facility comprising: (a) transformer means having first and second windings, said first winding being connected to said cable facility and said second winding having first and second terminals; and (b) impedance generating means connected between said second winding and said transmission device comprising: (i) first selectable switch means for selecting one of a predetermined number of resistances each of said resistances being associated with a selected one of a predetermined number of selectable impedances; and (ii) negative resistance generating means having an input and an output and including an adjustable value resistance means, said first selectable means being connected between said first terminal and said input, said output being connected to said second terminal to thereby form a loop, said negative resistance generating means being responsive to the current flowing in said loop for presenting a constant value negative resistance at said second terminal, the value of said negative resistance being determined by the setting of said adjustable value resistance means, such that said circuit provides to said cable facility said selected one of said predetermined number of selectable impedances.
Claim 10
Dependent Claim
193 words
A compensated circuit for use in interfacing a transmission device to a cable facility comprising: (a) transformer means having first and second windings, said first winding being connected to said cable facility and said second winding having first and second terminals; and (b) impedance generating means connected between said second winding and said transmission device comprising: (i) first selectable switch means for selecting one of a predetermined number of resistances each of said resistances being associated with a selected one of a predetermined number of selectable impedances; and (ii) negative resistance generating means having an input and an output and including an adjustable value resistance means, said first selectable means being connected between said first terminal and said input, said output being connected to said second terminal to thereby form a loop, said negative resistance generating means being responsive to the current flowing in said loop for presenting a constant value negative resistance at said second terminal, the value of said negative resistance being determined by the setting of said adjustable value resistance means, such that said circuit provides to said cable facility said selected one of said predetermined number of selectable impedances.
Claim 11
Dependent Claim
60 words
The circuit of claim 8 wherein said negative resistance generating means further includes a temperature compensated resistance means having a resistivity temperature coefficient selected to be opposite in phase to the resistivity temperature coefficient of said first and second windings such that said circuit provides said selected one of said predetermined number of selectable impedances independent of changes in temperature.
Claim 12
Dependent Claim
49 words
The circuit of claim 8 wherein said first selectable switch means includes first and second resistors connected in series between said first terminal and said negative resistance generating means input and first and second switch means connected in parallel across a respective one of said first and second resistors.
Claim 13
Dependent Claim
49 words
The circuit of claim 9 wherein said first selectable switch means include first and second resistors connected in series between said first terminal and said negative resistance generating means input and first and second switch means connected in parallel across a respective one of said first and second resistors.
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) | 1988-11-18 | 1989-05-20 | 1989-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-18 | 1993-05-20 | 1993-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-18 | 1997-05-20 | 1997-11-19 | $7700.00 | Window Closed / Lapsed |