Jirsa R E, Norris T W
Scand Audiol. 1977;6(2):69-72. doi: 10.3109/01050397709045000.
This study was designed to examine relationships between measures of total distortion (TD) and individual 2nd and 3rd harmonic distortion in various types of hearing aids. Measures of 2nd harmonic, 3rd harmonic, and TD were determined for six instruments. Analysis of the results revealed that little additional information is obtained from a measure of TD as opposed to individual harmonic measures. Furthermore, in two instances TD measures resulted in erroneously high distortion readings because of ambient and system noise. It is recommended that in less than ideal acoustic environments, measures of 2nd and 3rd harmonic distortion be used in lieu of TD.
本研究旨在考察各类助听器中总失真（TD）测量值与二次和三次谐波失真测量值之间的关系。对六种仪器的二次谐波、三次谐波和总失真进行了测量。结果分析表明，与单独的谐波测量相比，总失真测量几乎无法获得更多信息。此外，在两种情况下，由于环境噪声和系统噪声，总失真测量得出的失真读数过高。建议在声学环境不理想的情况下，使用二次和三次谐波失真测量值代替总失真测量值。
