Radiocommunications Agency  EMC Awareness

Mitigation

EMC can be addressed in product and system design in several ways. Classical techniques involve grounding, filtering and shielding and these must be implemented correctly in order to be successful. Modern electronics has greater potential to create and suffer from interference, and the actual choice of circuit technology and configuration has an impact. Cable design and routing and structural design also have a part to play. The design of radio systems themselves can minimise the impact of unavoidable interference.

This section includes an overview of each of the various mitigation techniques that are available. It is no more than an introduction to each, since in many cases whole books can be written discussing their detailed implementation. Where relevant, there will be a section devoted to applying the technique in product design, and a companion section referring to installation techniques, since in most cases there are differences in application. Another section labelled “Resources” points you towards further reading and relevant sources on the web.

Mitigation Techniques

	Installation	Design & Development	Resources
Adjacent channel rejection and bandpass filtering
Transmitter frequency control
Co-channel rejection
Preventing intermodulation
Preventing unintentional RF demodulation
Filtering
Filtering with cable-mounted CM chokes
Shielding of areas and volumes
Shielding of cables
Circuit design for RF stability, spurious suppression
Circuit design for emissions control
PCB layout
Bonding
Balanced interconnections and twisted pairs
Cable routing
Segregation
Software design for immunity
Suppressing arcs and sparks
Power harmonic reduction