Patent US2790970A successfully refreshed from Google Patents.
US2790970A
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Audio frequency signal transfer control circuits
Assignee: Sprague Electric Co
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Filing: 1951-01-04
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Granted: 1957-04-30
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Expires: 1971-01-04
Abstract
No abstract record available.
Inventors
- 👤 George T Kodama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:00
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/02; H03G3/04; H03G3/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1620020A
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GB329747A
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US2106336A
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US2145372A
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FR849954A
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US2309068A
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US2361657A
Cited
US2326341A
Cited
US2474988A
Cited
US2386651A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-04-29 | 1960-10-29 | 1961-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-04-29 | 1964-10-29 | 1965-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-04-29 | 1968-10-29 | 1969-04-30 | $7700.00 | Window Closed / Lapsed |