Diagnostic Evaluation of Radiated Emissions from Information Technology Equipment Using a Ferrite Absorbing Clamp and Current Probe

The control of electromagnetic radiation from information technology equipment (ITE) is an essential feature in the design of products which are marketed in regions where mandatory regulations exist.

It is essential that the designer has available some diagnostic tools which enable him to predict with reasonable accuracy whether the product will pass the EMC certification test.

The dominant radiated emissions from a system interlinked by interface and power cables is often associated with cable radiation.

This report details programmes of work devised to investigate the use of generally availale EMC laboratory tools in the determination of compliance, in a development-laboratory environment.

Two devices - a ferrite absorbing clamp and a current transformer were selected and applied to the measurement of emissions from a small computer system comprising a host computer and peripherals linked by interface cables.

The tests are summarized and the results analyzed, some comparisons are made and conclusions drawn.

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