US5249228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cable television signal scrambling system
Assignee: RCA Licensing Corp
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Filing: 1992-06-22
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Granted: 1993-09-28
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Expires: 2012-06-22
Abstract
Abstract In a cable television system an interferer signal is inserted into the video signal for scrambling purposes except during a vertical blanking reference interval containing a reference signal for use by a video equalizer in a television receiver to help reduce multipath distortion such as image ghosts.
Inventors
- 👤 Charles B. Dieterich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:42
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/166
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
110 words
In a television signal transmitter system for providing a subscriber television signal containing image information intended to be viewed at receivers of subscribers and unviewable at receivers of non-subscribers, transmitter apparatus comprising: means for providing a television signal including video information to be displayed by a television signal receiver; means for providing an interferer signal for distorting said video information; means for selectively combining said television signal and said interferer signal except during a reference interval containing a reference signal for use by video signal channel phase or frequency equalizing means in a television receiver; and means for coupling an output of said combining means to a subscriber television channel.
Claim 2
Dependent Claim
110 words
In a television signal transmitter system for providing a subscriber television signal containing image information intended to be viewed at receivers of subscribers and unviewable at receivers of non-subscribers, transmitter apparatus comprising: means for providing a television signal including video information to be displayed by a television signal receiver; means for providing an interferer signal for distorting said video information; means for selectively combining said television signal and said interferer signal except during a reference interval containing a reference signal for use by video signal channel phase or frequency equalizing means in a television receiver; and means for coupling an output of said combining means to a subscriber television channel.
Claim 3
Dependent Claim
35 words
Apparatus according to claim 1, wherein said video information modulates a radio frequency video carrier; and said interferer signal is a radio frequency signal at a frequency other than the frequency of said video carrier.
Claim 4
Dependent Claim
37 words
Apparatus according to claim 2, wherein said interferer is a sinusoidal signal; and said video carrier and said interferer signal exhibit a frequency difference corresponding to a frequency within a baseband frequency range of said video information.
Claim 5
Dependent Claim
22 words
Apparatus according to claim 3, wherein said frequency difference corresponds to a frequency approximately in the middle of said baseband frequency range.
Claim 6
Dependent Claim
15 words
Apparatus according to claim 1, wherein said reference signal is a ghost cancelling reference signal.
Claim 7
Dependent Claim
15 words
Apparatus according to claim 5, wherein said reference interval is within a vertical blanking interval.
References Cited (Backward Citations)
US3347982A
Cited
US4748677A
Cited
US4621288A
Cited
US4777648A
Cited
US4912557A
Cited
US5065242A
Cited
US5133009A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-27 | 1997-03-29 | 1997-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-27 | 2001-03-29 | 2001-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-27 | 2005-03-29 | 2005-09-28 | $7700.00 | Window Closed / Lapsed |