Equipment Configuration during the Verification Tests


A very important part of the the compatiblity tests is the test method. Because the value obtained from measurements of RF are so dependent on layout and method, these have to be specified in some detail to generate a standard result.

It is often impossible to determine for a complex system the worst case configuration.

Plug-in cards must be tested in at least one appropriate host unit. To ensure compliance of a plug-in card, the test unit should be a compliant production sample.

Specific mode of operation of EUT are defined in the product standards.

Emission measurement requires a correct placement of the EUT with respect to the ground plane, the LISN, the disposition of the main cable and earth connection.

Another important thing in the emission is the definition of the configuration of the EUT during tests. An attempt shall be made to maximise the emission consistent with the typical applications by varying the configuration of the test sample . Interface cables shall be connected to the available interface ports of the test unit. This includes, but is not limited to, standard interface bus ports and I/O lines provided on the equipment.

The effect of varying the position of the cables shall be investigated to find the arrangement that produces the maximum emissions. The configuration shall be precisely noted in the test report. For immunity the tests shall be made in the most susceptible operating mode in the frequency band investigated consistent with normal applications. The configuration of the test sample shall be varied to achieve maximum susceptibility. If the apparatus is part of a system, or can be connected to the minimum configuration of auxilary apparatus it is necessary to exercise the ports. The configuration and mode of operation during the tests shall be precisely noted in the test report.

The most critical configuration and mode of operation are to be selected (worst case)

The length of I/O cables shall be varied to achieve maximum emission and susceptibility

One unit (module) of each type in the EUT shall be used (it's assumed that disturbances from identical modules are not additive);

For multiple ports of the same type, cables shall be connected to just one if multiple cables do not increase emission !