US1568142A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency selective circuits
Assignee: AT&T Inc
•
Filing: 1920-08-13
•
Granted: 1926-01-05
•
Expires: 1940-08-13
Abstract
No abstract record available.
Inventors
- 👤 Henry W Elsasser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:27
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/17; H03H7/1741; H03H7/1783; H03H7/0115; H03H7/1791
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1929-01-04 | 1929-07-06 | 1930-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1933-01-04 | 1933-07-06 | 1934-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1937-01-04 | 1937-07-06 | 1938-01-05 | $7700.00 | Window Closed / Lapsed |