Patent US2297792A successfully refreshed from Google Patents.
Patent US4390893A successfully refreshed from Google Patents.
US4390893A
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US
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Digital color modulator
Assignee: National Semiconductor Corp
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Filing: 1980-12-15
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Granted: 1983-06-28
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Expires: 2000-12-15
Abstract
Abstract An interface circuit for converting a digital signal representing a dot-by-dot color video signal into a NTSC signal compatible with a television antenna input precompensates the digital for limitations in typical NTSC receivers. Various methods and circuits for precompensating the luminance amplitude, chrominance and chrominance amplitude content of the digital signal result in perceivably improved contrast and color purity.
Inventors
- 👤 Gilbert E. Russell
- 👤 Hee Wong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:04
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
52 words
A method for precompensating a digital signal representing a dot-by-dot color video signal for the apparent high luminance of yellow in a NTSC format comprising the steps of: detecting a yellow dot; reducing the chrominance level of the yellow dot; and increasing the luminance level during the period of the yellow dot.
Claim 2
Independent Claim
52 words
A method for precompensating a digital signal representing a dot-by-dot color video signal for the apparent high luminance of yellow in a NTSC format comprising the steps of: detecting a yellow dot; reducing the chrominance level of the yellow dot; and increasing the luminance level during the period of the yellow dot.
Claim 3
Dependent Claim
19 words
A method as in claim 2 further comprises the step of converting the digital signal to a NTSC signal.
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) | 1986-06-27 | 1986-12-27 | 1987-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-27 | 1990-12-27 | 1991-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-27 | 1994-12-27 | 1995-06-28 | $7700.00 | Window Closed / Lapsed |