双路G．7 23．1在ADSP21 061上的实时实现

由于具有高音质和低码速率的特点，G．723．1被作为PSTN网上的可视电话的语音通信标准，并广泛应用于IP Phoen等其他语音通信领域。文中详细介绍了在ADSP21061上实时实现双路G．723．1编解码功能的软硬件设计。系统实现的关键难点是双路编解码算法的实时实现，因为采用原始的G．723．1算法，双路编解码系统无法实时的实现。通过采用作者提出的一个递推算法，双路G．723．1编解码算法所需要的计算量最多为26．9MIPS，从而能够在ADSP21061上实时实现。递推算法没有造成G．723．1算法数值的任何改变。由于ADSP21061是一个低价位芯片，所以该双路系统具有相当高的性能价格比，它已经在PSTN网上多媒体通信系统和数字语音记录仪上进行了推广应用。

Real-Time Realization of Bi-Channel G. 723.1 on ADSP21061

Because of the high quality and low bit rate, G.723.1 is selected as the speech communication standard of the multimedia terminal of PSTN, and is extensively used in other speech communication areas such as IP phone. This paper introduces in detail the software and hardware design used in the real time realization of bi channel G.723.1 on ADSP21061. The key difficulty is the real time realization of the bi channel encoding and decoding algorithm, because the bi channel system can't be realized if the original G.723.1 algorithm is used. A recursive algorithm is presented, the computation complexity of bi channel G.723.1 is no more than 36.9 MIPS, and the real time realization can be done on ADSP21061 using the algorithm. No numerical change is made on the G.723.1 algorithm. Because ADSP21061 is a low price chip, the bi channel system is of high capability to price ratio. It is now widely used on the multimedia terminal of PSTN and the digital speech recording instrument.