US3588622A
Expired / Lapsed
US
⏱️ 0.0 years remaining
D.c. cable driver circuit free from voltage variations between separated grounds
Assignee: GTE Automatic Electric Laboratories Inc
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Filing: 1969-04-14
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Granted: 1971-06-28
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Expires: 1989-04-14
Abstract
Abstract AN INTERFACE CIRCUIT IN EACH LINE OF A CABLE EXTENDING BETWEEN ELECTROMECHANICAL SWITCHES AND ELECTRONIC SWITCHES HAS HIGH IMPEDANCE TO NOISE SIGNALS INDUCED INTO THE LINE. THE NOISE IS INDUCED INTO THE LINE, PARTICULARLY INTO ITS COMMON GROUND RETURN PORTION, BY OPERATING CURRENTS OF THE ELECTROMECHANICAL SWITCHES. THE HIGH IMPEDANCE INTERFACE CIRCUIT SUBSTANTIALLY ELIMINATES THE CURRENT CAUSED BY NOISE AND THEREBY PREVENTS UNDESIRED OPERATION OF THE SENSITIVE ELECTRONIC SWITCHES. THE HIGH IMPEDANCE IS PROVIDED BY A TRANSISTOR CONNECTED IN THE TRANSMITTING END OF EACH LINE, THE TRANSISTOR BEING CONNECTED TO OPERATE IN A CONSTANT-CURRENT, UNSATURATED MODE.
Inventors
- 👤 Louis F Mankowski Jr
- 👤 Jeffrey P Mills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:33
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/0264; H04L25/0266; H03; H03K; H03K19/00; H03K19/0175; H03K19/018; H03K19/01825; H03K5/00; H03K5/01; H03K5/02; H04L25/028; H04L25/0292; H04Q; H04Q3/00; H04Q3/42; H04Q3/54; H04L25/0272
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-27 | 1974-12-27 | 1975-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-27 | 1978-12-27 | 1979-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-27 | 1982-12-27 | 1983-06-28 | $7700.00 | Window Closed / Lapsed |