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US3597529A
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System for the correction of differential phase distortion in a color television signal
Assignee: General Electric Co
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Filing: 1968-10-03
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Granted: 1971-08-03
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Expires: 1988-10-03
Abstract
Abstract A system for the correction of differential phase distortion in a color television signal in which an active filter is used to process the chroma components of a clipped portion of the video signal to generate a correction signal. The correction signal is added to the main video signal in quadrature to change differential phase with minimal change of frequency response and differential gain. The polarity and amount of correction can be varied.
Inventors
- 👤 Terry J Hickman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:40
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/77
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
165 words
A system for correcting differential phase distortion in a video signal incorporating chroma components, said system comprising: clipping means for clipping said video signal above a predetermined amplitude to provide a clipped signal corresponding to the portion of said video signal above said predetermined amplitude; first delay means responsive to said clipping means for imparting substantially a 180* phase delay to a signal at the subcarrier frequency; comparison means responsive to said clipping means and said first delay means for providing a correction signal of instantaneous amplitude dependent upon instantaneous difference in phase between output signals produced by said clipping means and said first delay means; second delay means for imparting to said video signal a phase delay of substantially 90* at said subcarrier frequency to provide a delayed subcarrier signal; and means responsive jointly to said comparison means and said second delay means for combining said correction signal and said delayed subcarrier signal to provide an output subcarrier signal having minimum differential phase distortion.
Claim 2
Independent Claim
165 words
A system for correcting differential phase distortion in a video signal incorporating chroma components, said system comprising: clipping means for clipping said video signal above a predetermined amplitude to provide a clipped signal corresponding to the portion of said video signal above said predetermined amplitude; first delay means responsive to said clipping means for imparting substantially a 180* phase delay to a signal at the subcarrier frequency; comparison means responsive to said clipping means and said first delay means for providing a correction signal of instantaneous amplitude dependent upon instantaneous difference in phase between output signals produced by said clipping means and said first delay means; second delay means for imparting to said video signal a phase delay of substantially 90* at said subcarrier frequency to provide a delayed subcarrier signal; and means responsive jointly to said comparison means and said second delay means for combining said correction signal and said delayed subcarrier signal to provide an output subcarrier signal having minimum differential phase distortion.
Claim 3
Dependent Claim
30 words
A system as defined in claim 1 including phase inverter means for selectively inverting said clipped signal, said phase inverter means coupling said clipped means to said first delay means.
Claim 4
Dependent Claim
15 words
A system as defined in claim 2 wherein said comparison means comprises a differential amplifier.
Claim 5
Dependent Claim
23 words
A system as defined in claim 3 wherein said combining means comprises means for adding said delayed subcarrier signal and said correction signal.
Claim 6
Dependent Claim
19 words
A system as defined in claim 4 whereiN said clipping means includes means for varying the clipping level thereof.
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) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |