A Study of Conducted-Emission Stable Source Applied to the EMC US and EU Standards

In this paper, a single-phase stable and inexpensive switching power supply (SPS), which gives three values when spectrum analyzer (SA) settings are setting in peak, quasi-peak and average detecting modes, is identified. These three modes are associated with the conducted emission measurement techniques called for in the US [1] and EU [2-4] standards. An uncertainty is another quality to describe the source stability. To address this issue, several measurements at four frequencies have been repeated five times in one-month span. The selected SPS is stable after 20 minutes. In order to have a stable source, the SPS needs more than 20 minutes as a warm up time. As a preliminary result, it is determined that an amplitude variation of ±1.0 dB can be achieved. Furthermore, the inter-laboratory correlation results in about 3 dB variations for the three modes of detection.