EMC aspects on grounding networks and DC power distribution in telecommunication systems

The possibility of creating galvanic isolation between two systems connected by means of coaxial cables while at the same time complying with the requirements on radiated emission from the signals on the coaxial cables, are discussed. Approximate requirements for transfer impedance for different signal speeds are also given. Induced noise voltages on shielded signal cables and internal connections inside shielded cabinets due to lightning strikes are discussed considering an isolated bonding network (IBN) with single-point connection to the common bonding network (CBN) and mesh-bonding network (MBN). The power feeding of cabinet and the filtering necessary to comply with the EMC requirements are discussed and a comparison of the filter arrangement for isolated DC return with unisolated DC return is demonstrated