IEC 61300-3-38:2012描述了表征无源器件和动态模块群延迟特性所需的测量方法。从这些测量值可以得到更多参数，如群延迟纹波、线性相位偏差、色散、色散斜率和相位纹波。此外，当使用解析极化进行这些测量时，还可以将差分群延迟确定为使用IEC 61300-3-32专用方法进行单独测量的替代方法。

IEC 61300-3-38:2012 describes the measurement methods necessary to characterise the group delay properties of passive devices and dynamic modules. From these measurements further parameters like group delay ripple, linear phase deviation, chromatic dispersion, dispersion slope, and phase ripple can be derived. In addition, when these measurements are made with resolved polarization, the differential group delay can also be determined as an alternative to separate measurement with the dedicated methods of IEC 61300-3-32.