NSA (the normalized site attenuation) measurement and theoretical calculation model of compact EMC chamber is firstly introduced in this paper.

本文首先介绍了紧缩型电磁兼容(EMC)暗室归一化场地衰减(nsa)的测试方法和理论值的计算模型。

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Objective the variations of the site and shape of focal region for a concave spherical ultrasound transducer in the case of high sound intensity and stronger attenuation were studied.

目的研究凹球面超声换能器的声焦域在高声强和媒质有较大衰减情况下，其形状和几何位置的变化。

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The ground reflection and attenuation must be properly accounted for in order to use the source spectrum measured at the site of the observer to predict the actual source spectrum in the free field.

为利用观察点处实测声频谱来预估实际声源自由场频谱特性，必须适当地计及地面反射和衰减效应的影响。

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