指定频率加权特性，命名为G，用于确定频谱部分或全部位于1 Hz至20 Hz频带内的声音或噪声的加权声压级。

Specifies a frequency-weighting characteristic, designated G, for the determination of weighted sound pressure levels of sound or noise whose spectrum lies partly or wholly within the frequency band from 1 Hz to 20 Hz.