US4065784A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for PCM-encoding NTSC color television at sub-Nyquist rate
Assignee: CBS Broadcasting Inc
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Filing: 1976-09-29
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Granted: 1977-12-27
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Expires: 1996-09-29
Abstract
Abstract NTSC television signals are digitally encoded at sub-Nyquist rates by placing the alias components into those parts of the spectrum not normally occupied by the luminance or chrominance components of the video signal. In a system described, the sampling frequency, f s , is exactly 2f sc + 1/4f h or 2f sc - 1/4f h , where f sc is the NTSC color subcarrier frequency and f h is the line-scan frequency. Most of the alias signals in the thus encoded signal are removed from the baseband video by comb filtering between f s - f y and f v , where f v is the baseband video bandwidth.
Inventors
- 👤 John P. Rossi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:58
CPC Classifications
H; H04; H04N; H04N11/00; H04N11/04; H04N11/042; H04N11/048
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
66 words
A method of digitally encoding an NTSC color television signal having a color subcarrier frequency f sc and a line-scan frequency f h , comprising the steps of: generating a first sampling signal having a frequency f s that differs from 2f sc by 1/4f h , sampling the television signals in response to the sampling signal, and converting the sampled television signal into digital form.
Claim 2
Independent Claim
66 words
A method of digitally encoding an NTSC color television signal having a color subcarrier frequency f sc and a line-scan frequency f h , comprising the steps of: generating a first sampling signal having a frequency f s that differs from 2f sc by 1/4f h , sampling the television signals in response to the sampling signal, and converting the sampled television signal into digital form.
Claim 3
Dependent Claim
24 words
The method according to claim 1, wherein said first sampling signal has a frequency f s equal to 2f sc + 1/4f h .
Claim 4
Dependent Claim
24 words
The method according to claim 1, wherein said first sampling signal has a frequency f s equal to 2f sc - 1/4f h .
Claim 5
Dependent Claim
57 words
The method according to claim 1, including the further steps of: producing a second sampling signal of the same frequency and in quadrature with said first sampling signal, alternately enabling the first and second sampling signals during successive horizontal scan lines of the television signals, and sampling the television signals in response to the enabled sampling signal.
Claim 6
Dependent Claim
33 words
The method according to claim 1, including the further step of: comb filtering the television signals before sampling to remove therefrom any (n + 1/4)f h energy components, where n is an integer.
Claim 7
Dependent Claim
69 words
Apparatus for digitally encoding an NTSC color television signal having a color subcarrier frequency f sc and a line-scan frequency f h , comprising, in combination, means for generating a first sampling signal having a frequency f s differing from 2f sc by 1/4f h , means for sampling the television signals in response to the sampling signal, and means for converting the sampled television signal into digital form.
Claim 8
Dependent Claim
69 words
Apparatus for digitally encoding an NTSC color television signal having a color subcarrier frequency f sc and a line-scan frequency f h , comprising, in combination, means for generating a first sampling signal having a frequency f s differing from 2f sc by 1/4f h , means for sampling the television signals in response to the sampling signal, and means for converting the sampled television signal into digital form.
Claim 9
Dependent Claim
75 words
Apparatus according to claim 6, further comprising: means for producing a second sampling signal of the same frequency and in quadrature with said first sampling signal, switching means responsive to the NTSC color television signal for alternately enabling said first and second signals during successive horizontal scan lines of said television signal, means responsive to the enabled sampling signal for sampling the television signal; and means for converting the sampled television signal into digital form.
Claim 10
Dependent Claim
23 words
Apparatus according to claim 6, wherein said first sampling signal has a frequency f s equal to 2f sc + 1/4f h .
Claim 11
Dependent Claim
25 words
Apparatus according to claim 7, wherein said first and second sampling signals have a frequency f s equal to 2f sc - 1/4f h .
References Cited (Backward Citations)
US3858240A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-26 | 1981-06-27 | 1981-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-26 | 1985-06-27 | 1985-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-26 | 1989-06-27 | 1989-12-27 | $7700.00 | Window Closed / Lapsed |