Patent DE113281C successfully refreshed from Google Patents.
US2188671A
Expired / Lapsed
US
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Wave amplifying system
Assignee: AT&T Inc
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Filing: 1938-03-29
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Granted: 1940-01-30
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Expires: 1958-03-29
Abstract
No abstract record available.
Inventors
- 👤 Ira G Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:12
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/10; H04B3/12; H03; H03F; H03F1/00; H03F1/34; H03F1/36; H03G; H03G1/00; H03G1/0005; H03G1/0035; H03G1/0041; H03G3/00; H03G3/02; H03G3/04; H03G3/06; H03G3/08
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) | 1943-01-29 | 1943-07-31 | 1944-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-01-29 | 1947-07-31 | 1948-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-01-29 | 1951-07-31 | 1952-01-30 | $7700.00 | Window Closed / Lapsed |