Patent US2931987A successfully refreshed from Google Patents.
US2931987A
Expired / Lapsed
US
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Cascade amplifier
Assignee: US Philips Corp
•
Filing: 1954-07-12
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Granted: 1960-04-05
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Expires: 1974-07-12
Abstract
No abstract record available.
Inventors
- 👤 Ensink Johannes
- 👤 Verhagen Jan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:41
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/34; H03F1/347
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2529459A
Cited
US2647957A
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US2659774A
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US2730576A
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US2774826A
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US2792553A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-04-05 | 1963-10-05 | 1964-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-04-05 | 1967-10-05 | 1968-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-04-05 | 1971-10-05 | 1972-04-05 | $7700.00 | Window Closed / Lapsed |