The design of the power supply electromagnetic interference filter needed to mitigate the conducted emission of electronic modules can be performed best if the magnitude of the common mode (CM) and that of the differential mode (DM) interference are known. In common test setups, the two terms can be obtained from the signals measured at the line impedance stabilization networks (LISNs) output ports using DM and CM rejection networks or through the postprocessing of the output signals in the time domain. Both these approaches rely on the perfect matching of the LISNs internal filters, which is not realistic. Indeed, the LISNs mismatch allow the DM to be measured as CM and vice versa. In this work, the influence of the LISNs mismatch on the separation of CM and DM is investigated and a fast and accurate method to do that is proposed.

中文翻译：

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从传导发射测量中评估共模和差模分量

如果已知共模 (CM) 和差模 (DM) 干扰的幅度，则可以最好地设计减轻电子模块传导发射所需的电源电磁干扰滤波器。在常见的测试设置中，这两项可以从使用 DM 和 CM 抑制网络的线路阻抗稳定网络 (LISN) 输出端口测量的信号或通过在时域中对输出信号进行后处理获得。这两种方法都依赖于 LISN 内部过滤器的完美匹配，这是不现实的。实际上，LISN 的不匹配允许将 DM 测量为 CM，反之亦然。在这项工作中，研究了 LISN 不匹配对 CM 和 DM 分离的影响，并提出了一种快速准确的方法。