EP0074810A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Subscription television system
Assignee: Sony Corp
•
Filing: 1982-09-09
•
Granted: —
•
Expires: 2002-09-09
Abstract
Abstract In a subscription television system, the video signals constituting a specific program has its video portion scrambled in accordance with a predetermined scrambling scheme and a key signal which is used for unscrambling the scrambled video signal is generated in response to the scrambling mode. The key signal is not transmitted until after termination of transmission of the specific program so that correct decoding of the signal in real time is not possible. Various scrambling schemes, including one for the audio part of the video signal are disclosed.
Inventors
- 👤 Yasushi C/O. Sony Corporation Fujiumura
- 👤 Takashi C/O. Sony Corporation Okada
- 👤 Kazuo C/O. Sony Corporation Yamagiwa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 07:20
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/00086; G11B20/0021; G11B20/00217; G11B20/00253; G11B20/00282; H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/913; H04N7/00; H04N7/16; H04N7/167; H04N7/1675; G06; G06F; G06F2211/00; G06F2211/007; H04N2005/91357; H04N2005/91364
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
74 words
A television system comprising means for scrambling at least either one of video signal and audio signal of specific programs in accordance with a predetermined scrambling scheme, characterised by means for generating a control signal in response to the predetermined scrambling scheme, said control signal including a key signal which is used for unscrambling the signal scrambled in said scrambling means, and means for transmitting said key signal after termination of said specific program.
Claim 2
Dependent Claim
74 words
A television system comprising means for scrambling at least either one of video signal and audio signal of specific programs in accordance with a predetermined scrambling scheme, characterised by means for generating a control signal in response to the predetermined scrambling scheme, said control signal including a key signal which is used for unscrambling the signal scrambled in said scrambling means, and means for transmitting said key signal after termination of said specific program.
Claim 3
Dependent Claim
21 words
A system according to claim 1, in which said scrambling means includes means for changing said scrambling mode for different programs.
Claim 4
Dependent Claim
29 words
A system according to claim 2, in which said control signal further includes a program code signal which is used for identifying said key signal for said specific program.
Claim 5
Dependent Claim
21 words
A system according to claim 3, in which said program code signal is transmitted before the transmission of said specific program.
Claim 6
Dependent Claim
78 words
For use in a television system, apparatus for unscrambling signals of specific program transmitted in a scrambled form, said apparatus being characterised in that it comprises: a recording medium; memory means for storing a key signal which is transmitted after termination of said specific program; means for reproducing said scrambled signal from said recording medium; and means for unscrambling said scrambled signal from said reproducing means in accordance with said key signal read out from said memory means.
Claim 7
Dependent Claim
78 words
For use in a television system, apparatus for unscrambling signals of specific program transmitted in a scrambled form, said apparatus being characterised in that it comprises: a recording medium; memory means for storing a key signal which is transmitted after termination of said specific program; means for reproducing said scrambled signal from said recording medium; and means for unscrambling said scrambled signal from said reproducing means in accordance with said key signal read out from said memory means.
Claim 8
Dependent Claim
47 words
Apparatus according to claim 5, in which said scrambled signal comprises a video signal which is scrambled only in its video portion, said video signal in use being supplied to said recording means to be synchronized with synchronizing signals of said video signal which are not scrambled.
Claim 9
Dependent Claim
40 words
Apparatus according to claim 6, in which said unscrambling means includes means for discriminating a program code signal, said program code in use being supplied to said memory means to read out said key signal of said specific program therefrom.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.