Patent US5430799A successfully refreshed from Google Patents.
US5430799A
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Multichannel television signal scrambling and descrambling system and method
Assignee: Multichannel Communications Science Inc
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Filing: 1994-04-25
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Granted: 1995-07-04
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Expires: 2014-04-25
Abstract
Abstract A multichannel television access control system is disclosed wherein processing of the broadband signal is performed by gated coherent RF injection on a plurality of channels, thereby effecting selective descrambling of an arbitrary subset of channels in a channel group. The system provides for a closed loop injection signal phasor control so as to maintain substantially constant relationship between the television signals and the injected signals. The combined signals are supplied to subscribers enabling the use of their cable ready equipment.
Inventors
- 👤 Ron D. Katznelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:05
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04L; H04L5/00; H04L5/02; H04L5/06; H04N7/08; H04N7/162; H04N7/1675; H04N7/169; H04N7/171; H04N7/1713
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
117 words
A method for processing a first broadband signal comprised of a plurality of television signals each having a specific phasor value, said method comprising the steps of: independently generating a second broadband signal comprised of a plurality of simultaneous radio frequency (RF) signals in RF coherence with at least one of said plurality of television signals, each of said plurality of simultaneous RF signals having a phasor value; combining said first broadband signal with said second broadband signal; and adjusting said phasor value of at least one of said plurality of simultaneous RF signals in accordance with the corresponding specific phasor values of said plurality of television signals, so as to maintain a substantially constant relationship therebetween.
Claim 2
Independent Claim
117 words
A method for processing a first broadband signal comprised of a plurality of television signals each having a specific phasor value, said method comprising the steps of: independently generating a second broadband signal comprised of a plurality of simultaneous radio frequency (RF) signals in RF coherence with at least one of said plurality of television signals, each of said plurality of simultaneous RF signals having a phasor value; combining said first broadband signal with said second broadband signal; and adjusting said phasor value of at least one of said plurality of simultaneous RF signals in accordance with the corresponding specific phasor values of said plurality of television signals, so as to maintain a substantially constant relationship therebetween.
Claim 3
Independent Claim
96 words
A method for processing a television signal having an active video period and a blanking period comprising the steps of: independently generating a modulated radio frequency (RF) signal having an amplitude and phase characterized by a phasor value and having a frequency substantially equal to that of said television signal, wherein the phasor value of said modulated RF signal during said blanking period is substantially different from the phasor value of said modulated RF signal during said active video period; and combining said modulated RF signal with said television signal to produce a processed television signal.
Claim 4
Independent Claim
96 words
A method for processing a television signal having an active video period and a blanking period comprising the steps of: independently generating a modulated radio frequency (RF) signal having an amplitude and phase characterized by a phasor value and having a frequency substantially equal to that of said television signal, wherein the phasor value of said modulated RF signal during said blanking period is substantially different from the phasor value of said modulated RF signal during said active video period; and combining said modulated RF signal with said television signal to produce a processed television signal.
Claim 5
Dependent Claim
19 words
The method of claim 2, wherein said television signal is scrambled, said scrambled television signal having suppressed synchronizing pulses.
Claim 6
Dependent Claim
25 words
The method of claim 3, wherein said modulated RF signal is coherently combined substantially in phase with said scrambled television signal during said blanking period.
Claim 7
Dependent Claim
26 words
The method of claim 3, wherein said modulated RF signal is coherently combined substantially out of phase with said scrambled television signal during said blanking period.
Claim 8
Dependent Claim
41 words
The method of claim 2, wherein the amplitude of said modulated RF signal has a substantially zero value during said active video period such that said processed television signal is substantially identical to said television signal during said active video period.
Claim 9
Dependent Claim
42 words
The method of claim 2, wherein the frequency power spectrum of said modulated RF signal is substantially zero at the audio subcarrier frequency of a second television signal transmitted at a lower frequency channel adjacent to the channel of said television signal.
Claim 10
Dependent Claim
20 words
The method of claim 2, wherein the frequency power spectrum of said modulated RF signal is vestigial sideband in character.
Claim 11
Dependent Claim
23 words
The method of claim 1, wherein at least a portion of said plurality of television signals are transmitted with incrementally related carrier frequencies.
Claim 12
Dependent Claim
19 words
The method of claim 2 wherein said modulated RF signal is coherent with a carrier of said television signal.
Claim 13
Dependent Claim
22 words
The method of claim 10, wherein said modulated RF signal is coherently combined substantially out of phase with said scrambled television signal.
Claim 14
Dependent Claim
26 words
The method of claim 3, wherein said modulated RF signal is coherently combined substantially in phase with said scrambled television signal during said active video period.
Claim 15
Dependent Claim
41 words
The method of claim 10, further comprising the step of selecting a phasor value for said modulated RF signal during said active video period from a predetermined plurality of fixed and distinct phasor values in response to a cryptographic keystream control.
Claim 16
Dependent Claim
13 words
The method of claim 2, applied simultaneously to a plurality of television signals.
Claim 17
Dependent Claim
23 words
The method of claim 1, wherein said method is applied in a multichannel television transmission origination facility, thereby transmitting the processed broadband signal.
Claim 18
Dependent Claim
33 words
The method of claim 1, wherein said method is applied in a broadband receiving node, responsive to a broadband multichannel television transmission origination facility, thereby distributing said broadband processed signal to subscriber terminals.
Claim 19
Dependent Claim
87 words
The method of claim 15, wherein at least two of said plurality of television signals have frequencies that are incrementally related by frequency increments that are integral multiples of a predetermined fundamental frequency, said method further comprising the steps of: generating an RF pilot reference signal having a frequency equal to an integral multiple of said predetermined fundamental frequency; and combining said pilot reference signal with said processed broadband signal to produce a composite processed broadband signal; and transmitting said composite processed broadband signal to receiving nodes.
Claim 20
Dependent Claim
104 words
The method of claim 16, wherein at least two of said plurality of television signals have frequencies that are incrementally related by frequency increments that are integral multiples of a predetermined fundamental frequency, and wherein an RF pilot reference signal having a frequency equal to an integral multiple of said predetermined fundamental frequency is transmitted from said broadband multichannel television transmission origination facility, the method further comprising the steps of: receiving said RF pilot reference signal; regenerating a local reference signal phase locked to said received RF pilot reference signal; and using said local reference signal to generate said plurality of simultaneous RF signals.
Claim 21
Dependent Claim
20 words
The method of claim 14, wherein at least two of said plurality of television signals are modulated in video synchrony.
Claim 22
Dependent Claim
20 words
The method of claim 1, wherein at least two of said plurality of television signals are modulated in video synchrony.
References Cited (Backward Citations)
US3852519A
Cited
US4253114A
Cited
US4330794A
Cited
US4558358A
Cited
US4598312A
Cited
US4598313A
Cited
US4825468A
Cited
US4864613A
Cited
US4926477A
Cited
US5125100A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-07-03 | 1999-01-02 | 1999-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-03 | 2003-01-02 | 2003-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-03 | 2007-01-02 | 2007-07-04 | $7700.00 | Window Closed / Lapsed |