Patent US3821631A successfully refreshed from Google Patents.
US3821631A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for shifting the phase of a sine wave by differential means
Assignee: Western Atlas Inc
•
Filing: 1972-09-07
•
Granted: 1974-06-28
•
Expires: 1992-09-07
Abstract
Abstract A PHASE-SHIFT NETWORK AND A DIFFERENTIAL AMPLIFIER SHIFT THE PHASE OF AN AC INPUT VOLTAGE BY A PREDETERMINED AMOUNT TO PRODUCE A SINE WAVE VOLTAGE WHICH MAY ALSO REFERENCE TO A CIRCUIT COMMON VOLTAGE.
Inventors
- 👤 A Betke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:09
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/02; H02M7/04; H02M7/12; H02M7/145; H02M7/155; H02M7/162; H02M7/1623
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) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |