Effects of the salience of pitch and periodicity information on the intelligibility of four-channel vocoded speech: Implications for cochlear implants
Effects of the salience of pitch and periodicity information on the intelligibility of four-channel vocoded speech: Implications for cochlear implants
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DOI：
10.1121/1.1310667
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发表时间：
2000-10-01
影响因子：
2.4
通讯作者：
Smith, C
中科院分区：
文献类型：
--
作者：
Faulkner, A;Rosen, S;Smith, C
最近对连续交错采样（CIS）人工耳蜗语音处理器的模拟使用的声学刺激只能提供音调、周期性和非周期性的微弱线索，尽管这些被认为是语音的重要感知因素。构建了模拟CIS处理器的四通道声码器，对语音衍生的周期性和音高信息的显著性进行了处理。通过显式编码，在浊音语音中使用基频后的脉冲载波，在浊音语音中使用噪声载波，从而提供了音调和周期性的最高显著性。其他处理器包括包络截止频率为32和400赫兹的噪声激发声码器。与使用包络调制噪声载波的声码器相比，使用基频后的脉冲载波在识别频率滑动方面具有更高的性能。保留周期性的处理器改善了辅音语音信息的感知，并且使用截止频率为400 Hz的包络调制噪声载波的连接话语跟踪速率略快于32 Hz。然而，通过所有处理器，辅音和元音识别，句子可理解性和连接话语跟踪率大致相似。对于这些语音任务，超过400hz包络调制噪声提供的弱信息的音高和周期性对性能没有实质性贡献。(C) 2000美国声学学会。[s0001 - 4966(00) 05810 - 0]。
Recent simulations of continuous interleaved sampling (CIS) cochlear implant speech processors have used acoustic stimulation that provides only weak cues to pitch, periodicity, and aperiodicity, although these are regarded as important perceptual factors of speech. Four-channel vocoders simulating CIS processors have been constructed, in which the salience of speech-derived periodicity and pitch information was manipulated. The highest salience of pitch and periodicity was provided by an explicit encoding, using a pulse carrier following fundamental frequency for voiced speech, and a noise carrier during voiceless speech. Other processors included noise-excited vocoders with envelope cutoff frequencies of 32 and 400 Hz. The use of a pulse carrier following fundamental frequency gave substantially higher performance in identification of frequency glides than did vocoders using envelope-modulated noise carriers. The perception of consonant voicing information was improved by processors that preserved periodicity, and connected discourse tracking rates were slightly faster with noise carriers modulated by envelopes with a cutoff frequency of 400 Hz compared to 32 Hz. However, consonant and vowel identification, sentence intelligibility, and connected discourse tracking rates were generally similar through all of the processors. For these speech tasks, pitch and periodicity beyond the weak information available from 400 Hz envelope-modulated noise did not contribute substantially to performance. (C) 2000 Acoustical Society of America. [S0001-4966(00)05810-0].