Patent US1611223A successfully refreshed from Google Patents.
US1611223A
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Apparatus for controlling the frequency of an alternating current
Assignee: AT&T Inc
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Filing: 1923-12-19
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Granted: 1926-12-21
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Expires: 1943-12-19
Abstract
No abstract record available.
Inventors
- 👤 Nyquist Harry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:56
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/066
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1929-12-20 | 1930-06-21 | 1930-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1933-12-20 | 1934-06-21 | 1934-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1937-12-20 | 1938-06-21 | 1938-12-21 | $7700.00 | Window Closed / Lapsed |