US2540643A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency-modulated carrier signal receiver
Assignee: Individual
•
Filing: 1940-01-12
•
Granted: 1951-02-06
•
Expires: 1960-01-12
Abstract
No abstract record available.
Inventors
- 👤 Edwin H Armstrong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:07
CPC Classifications
H; H03; H03G; H03G11/00; H03G11/004
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2058565A
Cited
US2083232A
Cited
US2170475A
Cited
US2152515A
Cited
US2150044A
Cited
US2170202A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-02-05 | 1954-08-07 | 1955-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-02-05 | 1958-08-07 | 1959-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-02-05 | 1962-08-07 | 1963-02-06 | $7700.00 | Window Closed / Lapsed |