Apparatus for receiving digital sound/data information

• US 4,744,080 A
• Filed: 02/27/1986
• Issued: 05/10/1988
• Est. Priority Date: 03/12/1985
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Murray, Bruce, Brennand, Peter R.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Scutch, III, Frank M.
• Application Number:
  US06/833,633
• Time in Patent Office: 803 Days
• Field of Search: 370/85, 370/94, 370/109, 340/825.5, 375/2.1
• US Class Current: 380/212
• CPC Class Codes: H04N 7/08 Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band , e.g. by time division H04N7/007 takes precedence
• CPC Class Codes: H04N 7/083 with signal insertion during the vertical and the horizontal blanking interval , e.g. MAC data signals

Abstract

A receiver for recovering sound/data information for a number of services transmitted digitally as a packet multiplex has the data, after demodulation, applied to a first unit (3) where it is resynchronized for application to a sync and data extraction unit (19). In the extraction unit (19) the data packets are processed and applied, at a different clock rate, to a packet bus (25) to which a desired number of packet digital sound recovery devices (26) and packet encryption recovery devices (27) are connected. Instead of each recovery device (26, 27) interrogating all the packets of data those packets carrying a service identification address are processed in the extraction unit (19) and service addresses for user selected services are applied from a microcomputer (23) over an I² C bus to the recovery devices (26, 27), control information also being received and interpreted by said extraction unit (19) and applied in similar manner to the recovery devices (26, 27).

Claims

1. A receiver for receiving and demodulating sound/data information for a number of services transmitted in digital form by means of a packet multiplex system where each packet comprises a header portion and a data portion, the header portion containing an address unique codes for which are allocated to each service with one address allocated to packets whose data portion contains service identification to facilitate the reception of a service in accordance with a user'"'"'s choice, the data portion of sound/data service packets being subjected to scrambling and containing either sound/data information or control information as to the coding scheme for such sound/data information, said receiver comprising a plurality of service recovery devices connected to a common packet bus for the recovery of a plurality of services, a recovery device being adapted to respond at any one time to an address code present in the packet header of packets for a selected service and to recover that service in accordance with the corresponding coding scheme, characterized in that said receiver additionally comprises means remote from said recovery devices for centrally receiving and interpreting all the packets carrying the service identification address to produce therefrom service addresses and for applying to one or more service recovery devices the or each respective service address for the or each user selected service, and means also remote from said recovery devices for centrally receiving and interpreting control information when present in said packets for said selected service or services and for applying to the associated recovery device or devices the coding interpretation information required as to the coding scheme for that or each selected service, and in that a packet encryption recovery device is connected to said common packet bus for the production of periodic initialization words in response to packets containing decryption information, said initialization words being applied to a service recovery device for controlling the descrambling of scrambled sound/data information, said means for centrally receiving and interpreting packets carrying the service identification address providing the or each address for the packet encryption recovery device.

2. A receiver as claimed in claim 1, characterized in that the packet encryption recovery device provides the initialization words for a plurality of service recovery devices.

3. A receiver as claimed in claim 1, characterized in that a plurality of packet encryption recovery devices are present each of which provides the initialization words for an associated service recovery device.

4. A receiver for receiving and demodulating sound/data information for a number of services transmitted in digital form by means of a packet multiplex system where each packet comprises a header portion and a data portion, the header portion containing an address unique codes for which are allocated to each service with one address allocated to packets whose data portion contains service identification to facilitate the reception of a service in accordance with a user'"'"'s choice, the data portion of sound/data service packets being subjected to scrambling and containing either sound/data information or control information as to the coding scheme for such sound/data information, said receiver comprising a plurality of service recovery devices connected to a common packet bus for the recovery of a plurality of services, a recovery device being adapted to respond at any one time to an address code present in the packet header of packets for a selected service and to recover that service in accordance with the corresponding coding scheme, characterized in that said receiver additionally comprises means remote from said recovery devices for centrally receiving and interpreting all the packets carrying the service identification address to produce therefrom service addresses and for applying to one or more service recovery devices the or each respective service address for the or each user selected service, and means also remote from said recovery devices for centrally receiving and interpreting control information when present in said packets for said selected service or services and for applying to the associated recovery device or devices the coding interpretation information required as to the coding scheme for that or each selected service, in that the number of service recovery devices for a particular type of service corresponds to the maximum number of such services that are to be recovered simultaneously, and in that a packet encryption recovery device is connected to said common packet bus for the production of periodic initialization words in response to packets containing decryption information, said initialization words being applied to a service recovery device for controlling the descrambling of scrambled sound/data information, said means for centrally receiving and interpreting packets carrying the service identification address providing the or each address for the packet encryption recovery device.

5. A receiver as claimed in claim 4, characterized in that the packet encryption recovery device provides the initialization words for a plurality of service recovery devices.

6. A receiver as claimed in claim 4, characterized in that a plurality of packet encryption recovery devices are present each of which provides the initialization words for an associated service recovery device.