IEC 60444-6:20 21作为IEC 60444-6:20 21 RLV提供，其中包含国际标准及其红线版本，显示了与上一版本相比技术内容的所有变化。IEC 60444-6:20 21适用于石英晶体单元的驱动电平依赖性（DLD）的测量。描述了两种测试方法（A和C）和一种参考方法（B）。基于根据IEC 60444-5的p网络的“方法A”可用于IEC 60444的这一部分所覆盖的整个频率范围。基于根据IEC 60444-5或IEC 60444-8的p网络或反射方法的“参考方法B”可用于IEC 60444的该部分覆盖的整个频率范围。“方法C”是一种振荡器方法，适用于具有固定条件的较大量基模晶体单元的测量。注:本文件中规定的测量方法不仅适用于AT切割，也适用于其他晶体切割和振动模式，如双旋转切割（IT、SC）和音叉晶体单元（通过使用高阻抗测试夹具）。与上一版相比，此版本包括以下重大技术变更: -一些方程式已被删除和更正； -在范围注释中已经规定，本文件中规定的测量方法不仅适用于AT切割，也适用于其他晶体切割和振动模式。

IEC 60444-6:2021 is available as IEC 60444-6:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60444-6:2021 applies to the measurements of drive level dependence (DLD) of quartz crystal units. Two test methods (A and C) and one referential method (B) are described. “Method A”, based on the p-network according to IEC 60444-5, can be used in the complete frequency range covered by this part of IEC 60444. “Reference Method B”, based on the p-network or reflection method according to IEC 60444-5 or IEC 60444-8 can be used in the complete frequency range covered by this part of IEC 60444. “Method C”, an oscillator method, is suitable for measurements of fundamental mode crystal units in larger quantities with fixed conditions.
NOTE The measurement methods specified in this document are not only applicable to AT-cut, but also to other crystal cuts and vibration modes, such as doubly rotated cuts (IT,SC) and to tuning fork crystal units (by using a high impedance test fixture). This edition includes the following significant technical changes with respect to the previous edition:
- some equations have been removed and corrected;
- it has been specified in the note of the Scope that the measurement methods specified in this document are not only applicable to AT-cut but also to other crystal cuts and vibration modes.