【摘要】 人工耳蜗的言语处理器中滤波器的性能好坏将影响听觉重建的效果.全相位滤波器具有阻带衰减快、相位不失真的优点,适用于人工耳蜗,但其计算复杂度较高,所以需要在满足声信号滤波设计准确度的前提下,确定参数最优的全相位滤波器.本文采用8通道全相位带通滤波器、频带均分,在不同阶数下对纯净的小提琴音旋律片段(生日快乐、两只老虎、音阶)进行带通滤波再合成,最后进行客观波形对比和主观测听评估.结果表明:不同阶数下的全相位滤波器的合成音会出现不同程度的波形失真和音质失谐,且滤波器阶数越高,幅频响应过渡带越陡,合成音的波形与音质越接近原始音;同时,其计算复杂度也会增大.对于音乐信号,当滤波器阶数高于70阶左右时,其音质不会出现失谐,且信号波形失真较小.更多还原

【Abstract】 The performance of filter in Cochlear Implant(CI)speech processor will affect the effect of auditory reconstruction.The all-phase filter has the advantages of fast stop-band attenuation and undistorted phase,which is suitable for CI,but its computational complexity is high,so it is necessary to determine the parameter optimal all-phase filter on the premise of ensuring the performance of CI.In this paper,8-channel all-phase band-pass filters are used,and the frequency band is evenly divided,the pure violin melody fragments(happy birthday,two tigers,octaves)were band-pass filtered and re-synthesized at different orders,and then the objective waveform comparison and subjective listening evaluation were conducted.The results show that the synthesized sound of the all-phase filter at different orders will have different degree of waveform distortion and sound quality detuning,and the higher the filter order is,the steeper the transition band of amplitude frequency response is,the closer the synthetic sound’s waveform and sound quality are to the original sound;at the same time,the computational complexity will increase.For music signals,when the filter order is higher than 70,the sound quality will not be detuned and the waveform error distortion will be small.更多还原