By researching the frequency difference between telephone channel and traditional channel, the phantom formants are found, which can be reduced by normalization of its residues.

• 通过研究电话信道对频谱包络的影响,从留数角度分析虚峰出现的原因,结合留数归一化方法和传统的倒谱均值减,对中间维的倒谱加以提升。