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提出了一种改进的多带激励 ( Modified multi- band excitation,MMBE)语音压缩编码算法以适用于低码率通信系统。作为一种多带激励 ( Multi- band excitation,MBE)编码器 ,MMBE根据重构信号谱与原始信号谱之间的相似程度来进行基音估计和浊清音判决 ,而其中基音参数的估计准确性将直接影响编码器的性能。文中提出的 MMBE算法采用了一种改进的基音估计算法以及基音轨迹跟踪方法 ,利用该方法既能保证基音周期的估计准确性 ,又能保证基音演变的平滑性。非正式主观测试表明 ,在相同码率下由 MMBE重建的语音质量明显优于 IMARSART- M标准IMBE,而在 3.2 kbps下能提供与之相近的语音质量
An improved multi-band excitation (MMBE) speech compression coding algorithm is proposed for low bit rate communication system. As a multi-band excitation (MBE) encoder, MMBE performs pitch estimation and voicing decision according to the similarities between the reconstructed signal spectrum and the original signal spectrum, and the estimation accuracy of the pitch parameters Directly affect the performance of the encoder. The proposed MMBE algorithm uses an improved pitch estimation algorithm and track pitch tracking method. By using this method, not only the accuracy of pitch period estimation but also the smoothness of pitch evolution can be guaranteed. Informal subjective tests show that the speech quality reconstructed by MMBE at the same code rate is significantly better than the IMARSART-M standard IMBE and provides comparable speech quality at 3.2 kbps