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中文核心期刊

基于全相位滤波器的电子耳蜗汉语音调感知及改进研究

The tone perception improvement of Putonghua in cochlear implant simulation based on the all phase DFT filter

  • 摘要: 针对电子耳蜗音调信息感知差的问题,在多导电子耳蜗机理模型的基础上,利用零(或全)相位滤波器以及希尔伯特变换,提取并分解16个通道信号的包络和精细结构,用多种方式嵌合成声音,对正常人耳测听合成音的音调信息,以确定信号的包络和精细结构对音调感知的影响。测试结果表明:精细结构相对包络对音调感知起着更重要的作用,且该作用主要表现在低频段(约1.2 kHz以内)通道上。研究发现,在固定通道上,精细结构与通道中心频率和相位信息决定的包络出现时刻对应,其音调感知与低通道电极刺激的脉冲发放时间有关。研究结论:在低频段电极上增加刺激脉冲发放时刻的控制对提高电子耳蜗音调感知是重要的,同时应注意滤波器的相位保真。

     

    Abstract: The current cochlear implant (CI) user is bad on the tone perception.Based on the mechanism of multi- channel cochlear implant,the relative perceptual importance of envelope and fine time structure for tile tone reception is studied by the auditory chimaera experiments,in which the envelope and fine time structure from 16 channel signals are extracted and decomposed by a type of zero (or all) phase DFT filter banks and Hilbert transformation,and then applied to synthesize the auditory chimaera in several manners.The tone perception results by the normal hearing listeners show that the fine time structure is more important to tone perception than the envelope,and the impact of the low channels below 1.2 kHz is more significant than that of the higher channels.We found,on the fixed channels,the fine time structure is correspond to the envelop timing,which is determined by the channel central frequency and phase information,and then effects on the electrode pulse firing time.So it is concluded that between the fixed channels the proper adding pulse firing time control on the low channel electrodes is vital for improving current CI tone perception, meanwhile the phase fidelity of filter banks is remarkable.

     

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