Patent US6328894B1 successfully refreshed from Google Patents.
US2496031A
Expired / Lapsed
US
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Dual microphone sound detector system
Assignee: RCA Corp
•
Filing: 1947-12-30
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Granted: 1950-01-31
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Expires: 1967-12-30
Abstract
No abstract record available.
Inventors
- 👤 Leslie J Anderson
- 👤 Alfred H Kettler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:58
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/32; H04R1/40; H04R1/406; H04R3/00; H04R3/005; Y; Y10; Y10S; Y10S367/00; Y10S367/901
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-01-30 | 1953-08-01 | 1954-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-01-30 | 1957-08-01 | 1958-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-01-30 | 1961-08-01 | 1962-01-31 | $7700.00 | Window Closed / Lapsed |