Abstract :
Signal switching has been practiced in CATV headends as a means of achieving better utilization of a limited number of channels and for commercial deletion and non duplication substitution. In designing a headend switching system, several problems need to be addressed. A selection can be made between baseband and IF switching, each having advantages under certain conditions. Different types of hardware are available to implement switching operations, including mechanical switches and relays, and electronic switches. When multiple inputs or output are involved in a switching operation, differing methods may be employed to implement signal distribution, with the method selected affecting isolation, loss, and complexity.
