US4081827A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for encoding television signals
Assignee: Eastman Kodak Co
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Filing: 1976-09-27
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Granted: 1978-03-28
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Expires: 1996-09-27
Abstract
Abstract A method and apparatus for modifying a color television signal permits three types of information to be coded onto a single subcarrier. Preferably two chrominance signals and a low frequency luminance signal are modulated onto the subcarrier in different sets of two such signals per scan line, such different sets being alternated on a line-by-line basis. The signals of such a set of two while occurring simultaneously are displaced in phase on the subcarrier and the subcarrier frequency is preferably selected to be an odd multiple of one-quarter of the line frequency. By so selecting the subcarrier frequency, a combination of the subcarrier signal with a luminance signal may be effected in a manner allowing for subsequent signal separation by comb filtering.
Inventors
- 👤 William E. H. Hipwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:02
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/86
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
170 words
A signal modifying apparatus that is adapted to receive a color video signal of the type providing scene information on line-by-line basis at a predetermined line frequency and having a luminance component and first and second chrominance components, said signal modifying apparatus comprising: means for decoding such a video signal into a luminance signal representing the luminance component thereof and first and second ancillary signals representing respective chrominance components thereof; means for supplying a third ancillary signal; means for receiving said first, second and third ancillary signals and for suppressing, on an alternating basis line by line, one signal at a time from a set of at least two of said ancillary signals; means for modulating the two unsuppressed ancillary signals for a line onto a subcarrier of preselected frequency to produce a subcarrier signal, such means including means for establishing a phase displacement between such two unsuppressed ancillary signals; and means for combining at least a portion of said luminance signal and said subcarrier signal into a composite signal.
Claim 2
Dependent Claim
170 words
A signal modifying apparatus that is adapted to receive a color video signal of the type providing scene information on line-by-line basis at a predetermined line frequency and having a luminance component and first and second chrominance components, said signal modifying apparatus comprising: means for decoding such a video signal into a luminance signal representing the luminance component thereof and first and second ancillary signals representing respective chrominance components thereof; means for supplying a third ancillary signal; means for receiving said first, second and third ancillary signals and for suppressing, on an alternating basis line by line, one signal at a time from a set of at least two of said ancillary signals; means for modulating the two unsuppressed ancillary signals for a line onto a subcarrier of preselected frequency to produce a subcarrier signal, such means including means for establishing a phase displacement between such two unsuppressed ancillary signals; and means for combining at least a portion of said luminance signal and said subcarrier signal into a composite signal.
Claim 3
Dependent Claim
42 words
A signal modifying apparatus according to claim 1 wherein said supplying means is a circuit connected to receive said luminance signal, which circuit includes low-pass filtering means for isolating a low frequency portion of said luminance signal as said third ancillary signal.
Claim 4
Dependent Claim
34 words
A signal modifying apparatus according to claim 2 wherein said first and second ancillary signals are alternately suppressed and said preselected subcarrier frequency is an odd multiple of one quarter of the line frequency.
Claim 5
Dependent Claim
53 words
A signal modifying apparatus according to claim 2 wherein said combining means includes complementary filtering means for removing said low frequency portion from said luminance signal to produce a complementary high frequency luminance signal and summing means for adding that high frequency luminance signal to said subcarrier signal to produce a composite signal.
References Cited (Backward Citations)
US3162838A
Cited
US4001875A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-27 | 1981-09-26 | 1982-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-27 | 1985-09-26 | 1986-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-27 | 1989-09-26 | 1990-03-28 | $7700.00 | Window Closed / Lapsed |