小型ファンからの騒音中の純音成分の音質評価パラメータに関する新提案

抄録

For the purpose of physical evaluations of noise emission, the existing noise test codes for Information Technology Equipment, such as ISO 7779, ECMA-74 etc. state the two parallel parameters for prominent discrete tone detection, i.e., TNR (tone-to-noise ratio) and PR (prominence ratio). At present, these existing parameters are being used to evaluate each single discrete tone of question. However, real product noise emissions in the field are more complex and mixture of many harmonic, sub-harmonic, and other frequency components etc. Therefore, it may not be practical to evaluate tonal prominence by a single discrete tone only. To improve such situations, now, Ecma TC26 TG1 (Noise and vibration measurement of small air-moving device) investigates future possibility to apply new parameter T-TNR (total tone-to-noise ratio) and T-PR (total prominence ratio). This paper reports its progress and key issues to be addressed for future development of tonal prominence evaluation.