| 摘要 |
The system comprises a centrally located coding device (K) to which a modulated TV-signal from the cable net (10) is passed, and which within the band width of the TV-signal via an obfuscation signal generator (13) passes to the modulated TV-signal data for the respective obfuscation signal such as time duration and frequency of the obfuscation signal. - For each subscriber a decoder (AK) comprising a sync unit and a filter is provided and is adapted to receive obfuscation coded signals from the coding device (12), and, in dependence on control signals from the control and communication devices (12) on one hand, and the function of the sync unit on the other hand, to filtrate off the obfucation signals on the channels where normal receiving is authorized in order to pass to an output terminal only decoded information signal. |
