一种低速可编程的声码器设计与实现

Design and Implementation of a Low Bit Rate Programmable Vocoder

为增强数字语音通信的安全性,提高传输带宽的利用率,基于低速率SELP算法,设计了一种具有可编程、高并行度、可重构、安全性等特点的声码器.采用四级ALU单元、可变长VLIW专用指令集等设计,优化了复杂度高的功能模块,显著提高指令级并行度.仿真结果表明,该声码器在20MHz主频下完成0.6kbps的SELP算法的平均功耗为200mW,完成编解码的运算复杂度为12.5MIPS,低于相同工艺水平的通用DSP的40MIPS.

For the safety enhancement of digital speech communication and the utilization improvement of transmission channel bandwidth, a new special purpose processor for speech compression based on low bit-rate SELP algorithm is proposed, which characterizes programmable, high degree of parallelism, reconfigurable and safety. Four-stage recombinant ALU and variable length VLIW instruction set are adopted to optimize the function modules with high complexity and enhance the degree of instruction level paraUelism. Simulation results indicate that the average consumption is 200mW under the main frequency 20MHz when the vocoder implements the 0. 6kbps SELP algorithm, and the operating complexity of the voeoder is 12.5MIPS which is much lower than that of general purpose DSP under the same state of the art.