EP 0052655 A4 19860107 - TELEVISION SCRAMBLING AND UNSSCRAMBLING METHOD AND APPARATUS.
Title (en)
TELEVISION SCRAMBLING AND UNSSCRAMBLING METHOD AND APPARATUS.
Title (de)
METHODE UND GERÄT ZUR VER- UND ENTSCHLÜSSELUNG VON FERNSEHSIGNALEN.
Title (fr)
PROCEDE ET DISPOSITIF DE BROUILLAGE ET DE DECODAGE DE SIGNAUX DE TELEVISION.
Publication
Application
Priority
US 15316480 A 19800527
Abstract (en)
[origin: WO8103593A1] Method and apparatus for scrambling and unscrambling television signals to prevent reception of acceptable signals by an unauthorized television receiver while maintaining the television signal recoverable by an authorized receiver. The present invention can also be used for reducing the necessary carrier signal power of a television transmitter. A transmitter (12) passes a television signal through at least one linear filter (30, 32, and 34) of the type that produces multiple time delayed signals of differing time delays. A receiver (14) receives the multiple time delayed signals from the transmitter and passes them through at least one linear filter (64, 66 and 68) to add the signals together so that one signal representative of the original is reinforced, allowing acceptable reception by an authorized viewer. In one arrangement, the linear filters are SAW devices. In an other arrangement, the linear filters of a type employing charge coupled devices and in yet another arrangement, the linear filters are of digital types. In yet another arrangement, high frequency linear filters are of a ferromagnetic type. Different scrambling codes are achieved.
IPC 1-7
IPC 8 full level
H04N 7/16 (2006.01); H04N 7/169 (2006.01); H04N 7/171 (2006.01)
CPC (source: EP)
H04N 7/169 (2013.01)
Citation (search report)
- [X] US 4170757 A 19791009 - DE SANTIS CHARLES M [US], et al
- [X] US 3936749 A 19760203 - GUILLEMIN ERNST A
Designated contracting state (EPC)
AT CH DE FR GB LU NL SE
DOCDB simple family (publication)
WO 8103593 A1 19811210; EP 0052655 A1 19820602; EP 0052655 A4 19860107; JP S57500908 A 19820520
DOCDB simple family (application)
US 8100441 W 19810406; EP 81901828 A 19810406; JP 50231981 A 19810406