Tailoring of EMI/EMC specifications and test plans

Naval shipboard electronic systems are required to operate in a very dense EM environment. Hence to achieve optimum performance, electromagnetic compatibility needs to be considered at par with other functional design parameters of the system/equipment. The applicability of the emission and susceptibility requirements of any generic standard such as MIL-STD 461C is dependent upon the type of equipment or subsystem. For a particular type of specified functional equipment, application of these standards is almost a routine issue, as per a given chart. The problem arises in the case of complex equipment like sonar, fire control systems, and radar systems with transmitter/receiver units combined. In such cases one has to take recourse to tailoring of the EMI/EMC specifications and test plans to evolve the most appropriate testing methodology for ensuring EMC compliance of the equipment under consideration. This paper brings out the considerations involved in tailoring of the system level EMI/EMC specifications and outlines the methodology adopted by this centre in executing the same, taking the example of a generic radar system with all its associated subsystems for greater elucidation