EP0196724A1
Expired / Lapsed
EP
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Scrambled television signals
Assignee: Koninklijke Philips NV
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Filing: 1984-05-10
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Granted: —
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Expires: 2004-05-10
Abstract
Abstract A television receiver for receiving scrambled television signals has an arrangement (3) which provides scrambled vision components (V) and packet arranged sound/data components (D) some of which are also scrambled. The components (D) are applied to a packet demuitiplexer (4) where the packets are assembled from the data in several lines in the signal to provide a first output (P) the respective packets carrying sound/data information and at a second output (E) encrypted control data which is applied to a sub-system (6) to produce a vision scrambling control word (VS) for each line of the vision components. The sub-system (6) during each line produces further bits which are applied to a descrambling control word generator (7) which assembles these further bits from three lines to form a packet scrambling control word. This control word and the packets associated with it are added in an adder (5) and applied to a main packet buffer store (8) from which each packet in read out by a packet selector (9) and the packet is applied to a packet descrambler (12) whilst the packet scrambling control word is selected by a register (11) and used to control the generation of a binary sequence by a pseudo random binary sequence generator (13) which sequence is added to the packet in the descrambler (12), modulo-two, to achieve descrambling. A packet identifier (10) examines the packet address to ensure the packet requires descrambling and inhibits the generator (13) should descrambling not be required. With such a receiver the data used for controlling descrambled of the sound/data components is obtained indirectly from the control data which improves security.
Inventors
- 👤 Derek Thomas Wright
- 👤 Gerald Offley Crowther
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 13:15
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04N7/1675
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
121 words
A method for scrambling or descrambling a television signal containing vision and digitally modulated sound/data components some of which components are to be scrambled or descrambled, characterised in the provision of control data which has a relatively low rate, producing a first binary sequence in response to said control data, which first binary sequence has a rate which is higher than that of said control data, producing a second binary sequence which is pseudo-random and which is periodically set from said first binary sequence, which second binary sequence has a rate which is higher than that of said first binary sequence, and employing said second binary sequence for the scrambling or descrambling of one of the components of said television signal.
Claim 2
Independent Claim
121 words
A method for scrambling or descrambling a television signal containing vision and digitally modulated sound/data components some of which components are to be scrambled or descrambled, characterised in the provision of control data which has a relatively low rate, producing a first binary sequence in response to said control data, which first binary sequence has a rate which is higher than that of said control data, producing a second binary sequence which is pseudo-random and which is periodically set from said first binary sequence, which second binary sequence has a rate which is higher than that of said first binary sequence, and employing said second binary sequence for the scrambling or descrambling of one of the components of said television signal.
Claim 3
Dependent Claim
119 words
- A method for scrambling or descrambling a television signal containing vision and digitally modulated sound/data components some of which are to be scrambled or descrambled, characterised in the provision of control data which has a relatively low rate, producing a first binary sequence in response to said control data, which first binary sequence has a rate which is higher than that of said control data, producing a second binary sequence which is pseudo-random and which is periodically set from said first binary sequence, said second binary sequence having a rate which is higher than that of said first binary sequence, and - employing said second binary sequence for the scrambling or descrambling of packets of the sound/data component.
Claim 4
Dependent Claim
119 words
- A method for scrambling or descrambling a television signal containing vision and digitally modulated sound/data components some of which are to be scrambled or descrambled, characterised in the provision of control data which has a relatively low rate, producing a first binary sequence in response to said control data, which first binary sequence has a rate which is higher than that of said control data, producing a second binary sequence which is pseudo-random and which is periodically set from said first binary sequence, said second binary sequence having a rate which is higher than that of said first binary sequence, and - employing said second binary sequence for the scrambling or descrambling of packets of the sound/data component.
Claim 5
Dependent Claim
28 words
A method as claimed in Claim 1 or 2, characterised in that said first binary sequence is also pseudo-random which sequence is periodically set by said control data.
Claim 6
Dependent Claim
47 words
A method as claimed in Claim 2 or Claim 3 when dependent on Claim 2, characterised in that the second binary sequence has a bit rate which corresponds to the bit rate of the packets to be scrambled or descrambled at the point of scrambling or descrambling.
Claim 7
Dependent Claim
133 words
A television receiver for receiving and processing a television signal containing vision and digitally modulated sound/data components some of which components are scrambled, characterised in that said receiver comprises means for recovering control data from said television signal which control data has a relatively low rate, means for producing a first binary sequence in response to said control data, which first binary sequence has a rate which is higher than that of said control data, means for producing a second binary sequence which is pseudo-random and which is periodically set from said first binary sequence, which second binary sequence has a rate which is higher than that of said first binary sequence, and means for employing said second binary sequence for the descrambling of one of the scrambled components of said television signal.
Claim 8
Dependent Claim
133 words
A television receiver for receiving and processing a television signal containing vision and digitally modulated sound/data components some of which components are scrambled, characterised in that said receiver comprises means for recovering control data from said television signal which control data has a relatively low rate, means for producing a first binary sequence in response to said control data, which first binary sequence has a rate which is higher than that of said control data, means for producing a second binary sequence which is pseudo-random and which is periodically set from said first binary sequence, which second binary sequence has a rate which is higher than that of said first binary sequence, and means for employing said second binary sequence for the descrambling of one of the scrambled components of said television signal.
Claim 9
Dependent Claim
129 words
A television receiver for receiving and processing a television signal containing vision and digitally modulated sound/data components some of which are scrambled, characterised in that said receiver comprises means for recovering control data from said television signal which control data has a relatively low rate, means for producing a first binary sequence in response to said control data, which first binary sequence has a rate which is higher than that of said control data, means for producing a second binary sequence which is pseudo-random and which is periodically set from said first binary sequence, said second binary sequence having a rate which is higher than that of said first binary sequence, and means for employing said second binary sequence for the descrambling of scrambled packets of the sound/data component.
Claim 10
Dependent Claim
129 words
A television receiver for receiving and processing a television signal containing vision and digitally modulated sound/data components some of which are scrambled, characterised in that said receiver comprises means for recovering control data from said television signal which control data has a relatively low rate, means for producing a first binary sequence in response to said control data, which first binary sequence has a rate which is higher than that of said control data, means for producing a second binary sequence which is pseudo-random and which is periodically set from said first binary sequence, said second binary sequence having a rate which is higher than that of said first binary sequence, and means for employing said second binary sequence for the descrambling of scrambled packets of the sound/data component.
Claim 11
Dependent Claim
29 words
A television receiver as claimed in Claim 5 or 6, characterised in that said first binary sequence is also pseudo-random which sequence is periodically set by said control data.
Claim 12
Dependent Claim
44 words
A television receiver as claimed in Claim 6 or Claim 7 when dependent on Claim 6, characterised in that the second binary sequence has a bit rate which corresponds to the bit rate of the packets to be descrambled at the point of descrambling.
References Cited (Backward Citations)
WO1983003731A1
Cited
WO1983003942A1
Cited
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