04528588 is referenced by 434 patents and cites 14 patents.

An information signal (INF) which is transmitted in coded form (CINF) from a signal source (RC) to a signal receiver (4,5) is decoded at the receiver and at the same time marked (MINF) by the introduction of an identification information (ID) which is characteristic of the receiver or its possessor. The signal from a video disc (RC) carrying a coded programme is decoded and marked before it is supplied to a television set (6). Via said identification information a so-called pirate copy is directly traceable to its originator. Thereby a protection against such copying is obtained. A device for the playback of a video disc of this type comprises a decoding and modification unit to which the necessary decoding information and identification information may be supplied from a personal data carrier (ID).

Title
Method and apparatus for marking the information content of an information carrying signal
Application Number
6/385374
Publication Number
4528588
Application Date
May 18, 1982
Publication Date
July 9, 1985
Inventor
Bo Lofberg
Vindragarvagen 12, S-117 40 Stockholm
SE
Agent
Frishauf Holtz Goodman & Woodward
IPC
G11B 15/04
G11B 5/86
H04N 7/16
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