A monitoring system for an RF transmission system, such as a multi-channel television broadcasting antenna feed system, gathers data about the physical and electrical condition of the RF transmission system in real time. The system can detect and localize deterioration and other time-dependent faults...http://www.google.com/patents/US7298396?utm_source=gb-gplus-sharePatent US7298396 - Apparatus and method for monitoring transmission systems using embedded test signals
