Patent US3518581A successfully refreshed from Google Patents.
US3518581A
Expired / Lapsed
US
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All-pass delay equalizer network
Assignee: Nortel Networks Ltd
•
Filing: 1967-09-21
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Granted: 1970-06-30
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Expires: 1987-09-21
Abstract
No abstract record available.
Inventors
- 👤 Brian Hughes
- 👤 Frederick T Halsey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:31
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/18; H03H7/19; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/14; H04B3/146; H04B3/147
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1955788A
Cited
US2029698A
Cited
US2002216A
Cited
US2029014A
Cited
US2567380A
Cited
US2585842A
Cited
US2585841A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-06-29 | 1973-12-29 | 1974-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-06-29 | 1977-12-29 | 1978-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-06-29 | 1981-12-29 | 1982-06-30 | $7700.00 | Window Closed / Lapsed |