Patent US2982536A successfully refreshed from Google Patents.
Patent US2874221A successfully refreshed from Google Patents.
US2874221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stereophonic transmission system
Assignee: US Philips Corp
•
Filing: 1956-01-13
•
Granted: 1959-02-17
•
Expires: 1976-01-13
Abstract
No abstract record available.
Inventors
- 👤 Dauguet Alexandre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:35
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; H04J; H04J7/00
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1962-02-16 | 1962-08-18 | 1963-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-02-16 | 1966-08-18 | 1967-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-02-16 | 1970-08-18 | 1971-02-17 | $7700.00 | Window Closed / Lapsed |