Patent EP0217689A1 successfully refreshed from Google Patents.
US2813974A
Expired / Lapsed
US
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Narrow band selective circuit arrangements
Assignee: Marconis Wireless Telegraph Co Ltd
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Filing: 1956-11-07
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Granted: 1957-11-19
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Expires: 1976-11-07
Abstract
No abstract record available.
Inventors
- 👤 Keall Oswold Edward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:02
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/1638; H03; H03D; H03D1/00; H03D1/22
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2256199A
Cited
US2723345A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-11-18 | 1961-05-20 | 1961-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-11-18 | 1965-05-20 | 1965-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-11-18 | 1969-05-20 | 1969-11-19 | $7700.00 | Window Closed / Lapsed |