Institute of Acoustics and Speech Communication, TU Dresden, 01062 Dresden, Germany.
Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Munich University Hospital, LMU, Munich, Germany.
J Acoust Soc Am. 2019 Jul;146(1):223. doi: 10.1121/1.5116137.
The estimation of formant frequencies from acoustic speech signals is mostly based on Linear Predictive Coding (LPC) algorithms. Since LPC is based on the source-filter model of speech production, the formant frequencies obtained are often implicitly regarded as those for an infinite glottal impedance, i.e., a closed glottis. However, previous studies have indicated that LPC-based formant estimates of vowels generated with a realistically varying glottal area may substantially differ from the resonances of the vocal tract with a closed glottis. In the present study, the deviation between closed-glottis resonances and LPC-estimated formants during phonation with different peak glottal areas has been systematically examined both using physical vocal tract models excited with a self-oscillating rubber model of the vocal folds, and by computer simulations of interacting source and filter models. Ten vocal tract resonators representing different vowels have been analyzed. The results showed that F1 increased with the peak area of the time-varying glottis, while F2 and F3 were not systematically affected. The effect of the peak glottal area on F1 was strongest for close-mid to close vowels, and more moderate for mid to open vowels.
从声学语音信号中估计共振峰频率主要基于线性预测编码 (LPC) 算法。由于 LPC 基于语音产生的源滤波器模型，因此获得的共振峰频率通常被隐含地视为无限声门阻抗（即闭合声门）的共振峰频率。然而，先前的研究表明，基于 LPC 的元音共振峰估计值与具有闭合声门的声道共振峰可能存在显著差异，因为这些元音的声门面积在实际变化。在本研究中，使用激励声带自激橡胶模型的物理声道模型以及源滤波器相互作用的计算机模拟，系统地研究了不同峰值声门面积发声时闭合声门共振峰与 LPC 估计的共振峰之间的偏差。分析了代表不同元音的 10 个声道共振器。结果表明，F1 随时间变化的声门峰值面积的增加而增加，而 F2 和 F3 没有系统地受到影响。对于闭中到闭元音，峰值声门面积对 F1 的影响最强，而对于中到开元音的影响则更为适中。
