Patent US2057857A successfully refreshed from Google Patents.
US2057857A
Expired / Lapsed
US
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Variable-gain amplifier arrangement
Assignee: Telefunken AG
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Filing: 1933-12-13
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Granted: 1936-10-20
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Expires: 1953-12-13
Abstract
No abstract record available.
Inventors
- 👤 Steimel Karl
- 👤 Klotz Ernst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:54
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/22
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) | 1939-10-20 | 1940-04-20 | 1940-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1943-10-20 | 1944-04-20 | 1944-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1947-10-20 | 1948-04-20 | 1948-10-20 | $7700.00 | Window Closed / Lapsed |