A CATV system includes a main head end as a system center and a plurality of subhead ends. A baseband TV signal is transmitted from the main head end to the subhead ends through optical fiber cables. A scrambling data generating means is disposed in the main head end to generate scrambling data and transmit...http://www.google.de/patents/US5008934?utm_source=gb-gplus-sharePatent US5008934 - CATV transmission system using scrambled signals
