通道声码器的话音质量

速率为2400bit/s的数字声码器,在窄带数字语言通信中,具有很重要的意义。本文提出用多个8085微处理器及部分专用硬件构成的通道声码器。它修改设计方便,为提高合成语言质量提供了灵活的实验手段。
文为了提高合成语言质量,提出了用全通滤波器改善激励函数特性,用调整数字滤波器带宽和相邻滤波器间的搭接方式来改善合成频响曲线和相位特性,并对汉语特征参量编解码提出了有效方法。所有这些都在合成语言的可懂度试验中得到证实。

SPEECH QUALITY OF CHANNEL VOCODER

2400 bit/s digital vocoder plays a very important role in narrow band speech communication. In this paper, a channel vocoder is presented, it is designed by using multiple 8085 microprocessors and some of special hardware.
The different designs can easily be modified in this efficient equipment to improve the quality of synthesis speech of the vocoder. In this study, special attentions were paid to the improvement of excitation signals by using all-pass filter, the combined response and group delay of the synthesis filter set that is adjusted by change bandwidth of filters and with antipolarity for adjacent filters, and the efficient method of encoding and decoding of Chinese speech parameters. The effect of all methods is obviously shown in the results of intelligibility tests.