US4737990A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Unauthorized channel jamming signal applying method for CATV system
Assignee: Pioneer Corp
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Filing: 1986-04-03
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Granted: 1988-04-12
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Expires: 2006-04-03
Abstract
Abstract In a jamming signal applying device connected between a cable and subscribers' terminal units in a CATV system, a signal for scrambling the video signal is produced in a time sharing mode, with the time sharing period being not uniform, and with sound disturbing long periods being mixedly interposed between picture disturbing short periods.
Inventors
- 👤 Shohei Kaneko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:30
CPC Classifications
H; H04; H04K; H04K3/00; H04K3/80; H04K3/82; H04K3/825; H04K3/40; H04K3/41; H04K3/42; H04N; H04N7/00; H04N7/16; H04N7/166; H04K2203/00; H04K2203/10; H04K2203/14
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
150 words
In a CATV system in which multi-channel video signals, each of said video signals being made up of an audio portion and a video portion, are transmitted through a cable, a channel jamming signal applying method comprising the steps of: producing a channel jamming signal containing sound jamming long periods of time T 1 for jamming said audio portion and picture jamming short periods of time T 2 for jamming said video portion, said channel jamming signal being produced in a time sharing mode with a time sharing period being nonuniform with respect to said sound jamming long periods of time T 1 and said picture jamming short periods of time T 2 , T 2 being less than T 1 and said periods of time T 2 occurring during said periods of time T 1 ; and introducing said jamming signal on a cable line to a subscriber's terminal.
Claim 2
Dependent Claim
150 words
In a CATV system in which multi-channel video signals, each of said video signals being made up of an audio portion and a video portion, are transmitted through a cable, a channel jamming signal applying method comprising the steps of: producing a channel jamming signal containing sound jamming long periods of time T 1 for jamming said audio portion and picture jamming short periods of time T 2 for jamming said video portion, said channel jamming signal being produced in a time sharing mode with a time sharing period being nonuniform with respect to said sound jamming long periods of time T 1 and said picture jamming short periods of time T 2 , T 2 being less than T 1 and said periods of time T 2 occurring during said periods of time T 1 ; and introducing said jamming signal on a cable line to a subscriber's terminal.
Claim 3
Dependent Claim
32 words
The jamming signal applying method of claim 1, wherein said long periods of time T 1 have a duration in a range of T 1 =1/(50 Hz) to T 1 1/(200 Hz).
Claim 4
Dependent Claim
68 words
The jamming signal applying method of claim 1, wherein said short periods of time T 2 are defined by T 2 =nt 2 , where n is a number of channels to be jammed and t 2 is an insertion time of said picture jamming short periods of time, wherein t 2 is approximately several tens of microseconds and n is in a range of 10 to 15.
Claim 5
Dependent Claim
29 words
The jamming signal applying method of claim 3, wherein T 2 is slightly removed from an integer multiple of a horizontal synchronizing frequency of video signals to be jammed.
Claim 6
Dependent Claim
51 words
The jamming signal applying method of claim 1, wherein the degree of sound scrambling is increased by increasing t 1 , an insertion time t 1 of said sound jamming long periods of time, said insertion time t 1 being an application time of said sound jamming long period of time.
Claim 7
Dependent Claim
49 words
The jamming signal applying method of claim 3, wherein the degree of picture scrambling is increased by increasing t 2 , said insertion time of said picture jamming short periods of time, said insertion time t 2 being the application time of said picture jamming short period of time.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |