The second chapter introduced the fundamental theories of harmonic analysis and the main methods of harmonic detection, then made a brief direction of harmonic administration.

第二章介绍了谐波分析的基本原理和谐波测量的主要方法，然后对电力系统的谐波管理作了简要说明。

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According to the nonlinear re-radiation characteristic of semiconductor PN node, the nonlinear node detection system for semiconductor junction targets based on second harmonic reception is designed.

根据非线性半导体p N结再辐射特性，设计了一种基于二次谐波接收的非线性节点探测系统。

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