Patent USRE28021E successfully refreshed from Google Patents.
USRE28021E
Expired / Lapsed
US
⏱️ 0.0 years remaining
Boxman etal chroma key circuit
Assignee: —
•
Filing: 1972-09-13
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Granted: 1974-05-28
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Expires: 1992-09-13
Abstract
Abstract A CIRCUIT FOR GENERATING AN OUTPUT PULSE UPON THE OCCURRENCE OF A SELECTED COLOR IN COLOR TELEVISION SIGNALS FEATURES A MATRIX TO FORM TWO CHROMINANCE DIFFERENCE SIGNALS. FOUR VARIABLE GAIN AMPLIIFERS MULTIPLY THE DIFFERENCE SIGNALS BY THE SINCE AND COSINE OF A CONTROL VOLTAGE WHICH IS A COURCE COLOR COLOUR. TWO CIRCUITS EACH COMPRISING A SUMMER, INVERTER, AND CLAMP CIRCUIT EACH ADD THE OUTPUTS OF TWO OF THE MULTIPLIED SIGNALS. AN AND GATE COMBINES THE OUTPUT OF THE SUMMER CIRCUITS AND ALSO IS COUPLED TO A VARIABLE BIAS SUPPLY, WHICH IS A FINE COLOR CONTROL. A DELAY LINE, A SECOND AND GATE, AND A CLIPPER AND ZERO REFERENCE THE SHAPE THE OUTPUT PULSE.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:04
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/74; H04N9/75
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) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |