In this article the implementation of DSP (TMS320C55X) for dual tone multiple frequency (DTMF) tone generation and detection is presented. Some knowledge of theoretical background regarding the algorithms for tone generation and detection is provided first, followed by the explanations on the implementation of specific digital signal processing ( DSP) in detail. High performance of the DTMF encoder and decoder in speed is achieved by using a buffered concept, which reduces the extra overhead of subprogram calling. The encoder and decoder are designed as C-callable reentrant functions, this enables the user to set up multi-channel tone detection in C without adding significant additional code and is easy to transplant into any given telephony application. Finally, the code is benchmarked in terms of its speed and the memory requirements are suggested as well. Both the MIPS and the memory requirements are reached to ideal states.%描述双音多频(DTMF)音产生与检测算法的TMS32OC55X实现.首先介绍DTMF音产生与检测算法的理论背景知识,接着对具体的数字信号处理(DSP)实现进行详细分析.采用缓冲的概念,DTMF编解码器在速度上实现高性能,降低了调用子程序的额外开销.编解码器设计成可调用C可嵌套函数,使用户可以在C环境建立多通道音频检测而无需另外加入大量的代码,易于植入到任何给定的电话系统.最后验证了代码的速度并给出对存储空间的要求.所需的MIPS和对内存的要求同时降至理想状态.
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