A method and apparatus for locating the source of noise ingress into a CATV system return path by coupling a filter having a passband in the noise frequency bandwidth to the nodes between adjacent return path amplifiers. The filter is sequentially coupled to the nodes, working away from the CATV system...http://www.google.ca/patents/US6292944?utm_source=gb-gplus-sharePatent US6292944 - Return path ingress in a two-way CATV system
