【摘要】 本文针对标准的2.4kb/s MELP声码器的不足之处提出了两项改进措施,一是提出了一种新的参数“能量—微分过零率比”,用来对语音的过渡段和弱能量浊音段的清浊音判决进行调整;二是对线谱对的多级矢量量化(MSVQ)提出了一种多径搜索算法。实验和主观听觉测试表明,在同样2.4kb/s的码率下,改进MELP声码器的合成语音在可懂度和自然度方面都有一定的提高。更多还原

【Abstract】 In this paper,two improvements on 2.4kb/s Mixed-Excitation linear Prediction(MELP) vocoder are presented.The one is a new parameter named Energy to Differential Zero-crossing Rate which is used in adaptation of V/UV decision of transitional segments and low energy level speech segments.The second is a multi-path searching method for multi-stage vector quantization(MSVQ) of line spectral frequency.Subjective tests show that the intelligiblity and naturallity of improved MELP vocoder are preferable to that of the original one.更多还原