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US2640919A
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Wave signal frequency-changing system with constant current biased frequency changing device
Assignee: Zenith Electronics LLC
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Filing: 1950-12-12
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Granted: 1953-06-02
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Expires: 1970-12-12
Abstract
No abstract record available.
Inventors
- 👤 John F Bell
- 👤 Roger M Nordby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:12
CPC Classifications
H; H03; H03D; H03D7/00; H03D7/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USRE18579E
Cited
US2436830A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-01 | 1956-12-01 | 1957-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-01 | 1960-12-01 | 1961-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-01 | 1964-12-01 | 1965-06-02 | $7700.00 | Window Closed / Lapsed |