The ESA1 is a system of EMC tools for relative measurements of interference emissions from assemblies and devices. The associated CS-ESA software enables the developer to quickly and comprehensibly suppress interference from the device under test. The interference emission measurements carried out with the ESA1 during development are proportional to the results of the far-field measurement or the measurement with network simulations. The ESA1 tools are used to localize sources of interference and identify the paths of interference emission. This allows suitable EMC measures to be derived and dimensioned. The improvements achieved with the ESA1 have a proportional effect on the result of the far-field measurement. The ESA1 is designed for the developer's workplace.