主题：请教耳机音频测试THD+N的测试方法

   在蓝牙耳机音频测试过程中，发现THD+N的测试结果不理想。THD大概是5%以下，比较不错，但是THD+N却是45%左右，好像太大了吧？由于没有过这方面的测试经验，不知道结果应该多少合适？

      网上查了一些资料，基本都是电信号测THD+N，很少有声信号测THD+N得介绍。

      想求助于各位，声信号的THD+N如何测试？合理值大约是多少？

 

THD + Noise
Total Harmonic Distortion plus Noise (THD+N) includes the distortion caused by noise in the test surroundings
and in the device(s) under test. The standard THD measurement only takes into account the magnitudes of
the Fundamental and following Harmonics, while the THD plus Noise measurement also measures the energy
between harmonics, and includes it as part of the distortion of the signal. The calculation includes the Total
Distortion (TD), the total noise power from the signal, including noise between the harmonics (TNP), and the
Fundamental (H1) to get the THD + Noise result.

 

THD + Noise公式见附件

 

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期待大虾出现，给予指导

用滤波器除去基波那是针对电信号，比如测试功放的THD+N可以采取这种方法，但测音频信号就不行了。

期待解答