The IEC 61000-4-21 and IEEE 299.1 documents report similar but not equal procedures to measure the shielding effectiveness (SE) of enclosures through the use of reverberation chambers. In this article, it is shown that these two measurement procedures can be merged in a single, enhanced, one. In particular, it is shown that the evaluation of the SE of enclosure in Annex H of IEC 61000-4-21, which exploits only mechanical stirring, can be improved by using the hybrid stirring, which includes also the frequency stirring, thus increasing the number of uncorrelated samples. On the other hand, it is shown that at low frequencies the evaluation of the SE of enclosures based on the definition in IEEE 299.1 can be improved through the use of the maximum values of measured powers rather than the average ones. The single, enhanced, proposed procedure provides more prudent SE values than the two standards at the low frequencies, especially for standard IEEE 299.1. The presented measurement approach is supported by results obtained in three different laboratories.

中文翻译：

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基于混响室测量的箱体屏蔽效能计算

IEC 61000-4-21 和 IEEE 299.1 文件报告了通过使用混响室来测量外壳屏蔽效率 (SE) 的类似但不相同的程序。在本文中，表明这两个测量程序可以合并为一个单一的、增强的、一个。特别是，IEC 61000-4-21 附录 H 中外壳的 SE 评估仅采用机械搅拌，可以通过使用混合搅拌（也包括频率搅拌）来改进，从而增加不相关样本的数量。另一方面，结果表明，在低频下，基于 IEEE 299.1 定义的外壳 SE 评估可以通过使用测量功率的最大值而不是平均值来改进。单一的，增强的，建议的程序在低频下提供比两个标准更谨慎的 SE 值，特别是对于标准 IEEE 299.1。所提出的测量方法得到了三个不同实验室获得的结果的支持。