EP0256596A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Decoding transmitted scrambled signals
Assignee: Koninklijke Philips NV
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Filing: 1987-08-06
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Granted: —
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Expires: 2007-08-06
Abstract
Abstract In a pay television system a programme signal is transmitted scrambled to prevent its authorised reception, the scrambled signal being accompanied by authorisation codes, one for each authorised subscriber, a subscription key and a pay-per-view key. At a receiver if the appropriate authorisation code is received the receiver functions in the subscription mode in which mode the subscription key provides for the descrambling of the programme signal. If the appropriate authorisation code is not received indicating that the subscriber is not pre-authorised to receive the programme in an intelligible manner, the receiver is set to function in a pay-per-view mode in which mode, on request, the pay-per-view key provides for the descrambling of the programme signal. If there is a delay receiving the appropriate authorisation code the receiver can be set into the pay-per-view mode for at least the period of the delay so that the scrambled signal is immediately rendered intelligible.
Inventors
- 👤 Gerald Offley Crowther
- 👤 Peter Robert Brennand
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 21:18
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/162; H04N21/00; H04N21/20; H04N21/25; H04N21/266; H04N21/26606; H04N21/40; H04N21/43; H04N21/44; H04N21/4405; H04N21/47; H04N21/472; H04N21/47211; H04N21/60; H04N21/63; H04N21/633; H04N21/6332; H04N21/6334; H04N21/63345; H04N7/167; H04N7/1675
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
234 words
A system for enabling a receiver to decode a transmitted scrambled signal which relates to a programme such that said programme may be obtained in an intelligible manner, wherein in addition to the scrambled signal there are additionally transmitted a subscription key and a pay-per-view key, the receiver functioning in a subscription mode in the event that the receiver is pre-authorised to obtain the programme in an intelligible manner with the scrambled signal being decoded under the control of the subscription key in the presence of an authorising code for the receiver whilst in the absence of such pre-authorisation the receiver is set to function in a pay-per-view mode in which case the programme, on request, is obtained in an intelligible manner with the scrambled signal being decoded under the control of the pay-per-view key, characterised in that when a delay exists between the selection of a channel carrying the said programme and the receipt of the appropriate authorising code such that in the event that the receiver is to function in the subscription mode the programme would not be received in an intelligible manner for the period of the delay, the receiver can be set to function in the pay-per-view mode during the period of the delay to receive the programme in an intelligible manner whereafter the receiver reverts to function in the subscription mode once the appropriate authorising code has been received.
Claim 2
Independent Claim
234 words
A system for enabling a receiver to decode a transmitted scrambled signal which relates to a programme such that said programme may be obtained in an intelligible manner, wherein in addition to the scrambled signal there are additionally transmitted a subscription key and a pay-per-view key, the receiver functioning in a subscription mode in the event that the receiver is pre-authorised to obtain the programme in an intelligible manner with the scrambled signal being decoded under the control of the subscription key in the presence of an authorising code for the receiver whilst in the absence of such pre-authorisation the receiver is set to function in a pay-per-view mode in which case the programme, on request, is obtained in an intelligible manner with the scrambled signal being decoded under the control of the pay-per-view key, characterised in that when a delay exists between the selection of a channel carrying the said programme and the receipt of the appropriate authorising code such that in the event that the receiver is to function in the subscription mode the programme would not be received in an intelligible manner for the period of the delay, the receiver can be set to function in the pay-per-view mode during the period of the delay to receive the programme in an intelligible manner whereafter the receiver reverts to function in the subscription mode once the appropriate authorising code has been received.
Claim 3
Dependent Claim
58 words
A system as claimed in Claim 1, characterised in that on the selection of a channel carrying the said programme the receiver is automatically set to function in the pay-per-view mode to provide during an initial period the programme in an intelligible manner, which initial period is at least as long as the said period of the delay.
Claim 4
Dependent Claim
65 words
A system as claimed in Claim 2, characterised in that by or at the end of said initial period said receiver is set to function in the subscription mode if the receiver is pre-authorised to receive said programme in an intelligible manner but if not so pre-authorised the receiver will continue to function in the pay-per-view mode and only decoder the scrambled signal if requested.
Claim 5
Dependent Claim
47 words
A system as claimed in Claim 1, 2 or 3, characterised in that the subscription key has a relatively short duration with a given subscription key pertaining to a given programme whilst the pay-per-view key is of longer duration and pertains to a number of consecutive programmes.
Claim 6
Dependent Claim
240 words
A receiver for use with a system as claimed in any of the preceding claims, said receiver comprising means for receiving a scrambled signal relating to a programme, means for receiving a subscription key, means for receiving a pay-per-view key, means for receiving authorising codes, means for descrambling said scrambled signal to provide said programme in an intelligible manner, and descrambling control means for controlling the operation of said descrambling means, said receiver functioning in a subscription mode in the event that the descrambling control means receives an authorising code appropriate to the receiver which confirms that the receiver is pre-authorised to obtain the programme in an intelligible manner whereby the scrambled signal is descrambled under the control of said subscription key, whilst in the absence of an authorising code relevant to the said receiver it is set to function in a pay-per-view mode in which case the scrambled signal is descrambled, on request, under the control of the pay-per-view key, characterised in that when a delay exists between the selection of a channel carrying the said programme and the appropriate authorising code being received whereby said programme is not produced in an intelligible manner for the period of said delay, said receiver additionally comprises means for setting the receiver to function in the pay-per-view mode during the period of the delay whereafter the receiver reverts to function in the subscription mode once the appropriate authorising code has been received.
Claim 7
Dependent Claim
61 words
A receiver as claimed in Claim 5, characterised in that means are provided for automatically setting said receiver to function in the pay-per-view mode on the selection of a channel carrying the said programme to provide during an initial period the programme in an intelligible manner, which initial period is at least as long as the said period of the delay.
Claim 8
Dependent Claim
62 words
A receiver as claimed in Claim 6, characterised in that means are provided for setting the receiver to function in the subscription mode at the end of said initial period in the event that the appropriate authorising code is received, said receiver continuing to function in the pay-per-view mode, if requested, in the event that the appropriate authorising code is not received.
References Cited (Backward Citations)
No citation records indexed.
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