US3895370A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-frequency communication system using A-C utility lines
Assignee: Italtel SpA
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Filing: 1973-07-02
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Granted: 1975-07-15
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Expires: 1993-07-02
Abstract
Abstract The conductors of an a-c (e.g. 60-cycle) utility line form a signal path for high-frequency communication, this path being bounded by two terminal coils each comprising a core which carries a plurality of low-inductance windings each in series with a respective line conductor. The windings all have the same number of turns so that, under normal operating conditions, the vector sum of their magnetomotive forces is zero. High-frequency transmitters and receivers are connected to one or more line conductors by being capacitively coupled thereto between the terminal coils or via respective supplemental windings on the cores of these coils. Ancillary windings on the coil cores may be used to detect an unbalance in the low-frequency current and to actuate protective devices for minimizing or stopping the flow of unbalance currents.
Inventors
- 👤 Nicola Valentini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:03
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/54; H04B3/56; F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1444; F02D41/1454; F02D41/1456; H04B2203/00; H04B2203/54; H04B2203/5462; H04B2203/5483; H04B2203/5487; H04B2203/5491; H04B2203/5495
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
194 words
In a power-supply system comprising a utility line with a plurality of parallel conductors normally carrying a substantially balanced low-frequency current between a source and a load, the combination therewith of: a pair of terminal coils at opposite ends of a transmission path including at least one of said conductors, each of said terminal coils comprising a plurality of windings on a common ferromagnetic core, said windings having the same number of turns and lying respectively in series with all conductors of said line whereby the vector sum of the magnetomotive forces normally induced by said windings in said core is substantially zero; transmitting means and receiving means for high-frequency signals; and first and second coupling means respectively connecting said transmission means and receiving means at spaced-apart points of said transmission path to said one of said conductors for communication with each other, said transmitting means and said receiving means being linked with each other by a return connection independent of said line, said first and second coupling means being separated from said source and said load by at least one winding on each coil for attenuating said highfrequency signals beyond said spaced-apart points.
Claim 2
Dependent Claim
194 words
In a power-supply system comprising a utility line with a plurality of parallel conductors normally carrying a substantially balanced low-frequency current between a source and a load, the combination therewith of: a pair of terminal coils at opposite ends of a transmission path including at least one of said conductors, each of said terminal coils comprising a plurality of windings on a common ferromagnetic core, said windings having the same number of turns and lying respectively in series with all conductors of said line whereby the vector sum of the magnetomotive forces normally induced by said windings in said core is substantially zero; transmitting means and receiving means for high-frequency signals; and first and second coupling means respectively connecting said transmission means and receiving means at spaced-apart points of said transmission path to said one of said conductors for communication with each other, said transmitting means and said receiving means being linked with each other by a return connection independent of said line, said first and second coupling means being separated from said source and said load by at least one winding on each coil for attenuating said highfrequency signals beyond said spaced-apart points.
Claim 3
Dependent Claim
30 words
The combination defined in claim 1 wherein said first and second coupling means comprise respective capacitors connected to said one of said conductors at points located between said terminal coils.
Claim 4
Dependent Claim
12 words
The combination defined in claim 1 wherein said return connection is ground.
Claim 5
Dependent Claim
42 words
The combination defined in claim 1 wherein said first and second coupling means comprise respective supplemental windings on the cores of said terminal coils, said return connection forming capacitive junctions with all conductors of said line at points beyond said terminal coils.
Claim 6
Dependent Claim
56 words
The combination defined in claim 4 wherein said transmitting and receiving means includes at least three stations intercommunicating via different frequency bands, said line being further provided with at least one intermediate coil substantially identical with said terminal coils, said stations being connected to supplemental windings on said terminal coils and on said intermediate coil, respectively.
Claim 7
Dependent Claim
43 words
The combination defined in claim 1, further comprising protective means for suppressing the flow of low-frequency unbalance currents in said line, and control means for said protective means including a monitoring winding on the core of at least one of said terminal coils.
Claim 8
Dependent Claim
17 words
The combination defined in claim 6 wherein said protective means comprises a circuit breaker in said line.
Claim 9
Dependent Claim
25 words
The combination defined in claim 6 wherein said protective means comprises switch means for closing a low-resistance circuit through an inductance wound on said core.
Claim 10
Dependent Claim
15 words
The combination defined in claim 8 wherein said inductance is constituted by said monitoring winding.
Claim 11
Dependent Claim
61 words
The combination defined in claim 9 wherein the core of each terminal coil is provided with a monitoring winding in series with a neutral conductor grounded at one end of said transmission path, said switch means being responsive to the flow of an unbalance current in either core for grounding said neutral conductor at a point remote from said one end.
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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) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |