DTMF信号的合成与识别

Synthesis and recognition of the DTMF signal

本系统以单片机和FPGA为控制核心,由DTMF信号合成模块与DTMF信号的识别模块构成。DTMF信号的合成是以直接数字频率合成技术(DDFS)为基础,根据按下键值,在FPGA内部合成一个双频数字信号,并通过D/A转换器输出。DTMF信号的识别是以Goertzel算法为核心,计算出8个频点的幅值,从而判断键值。经过测试,本系统能够达到DTMF信号的合成与识别要求。

The system uses SCM and FPGA as the control core, and consists by the DTMF signal synthesis module and the recognition module. The synthesis of DTMF signal is based on DDFS, according to press the key, a dual-band digital signal was synthesized in the FPGA and output by D/A converter. Recognition of DTMF signal uses the Goertzel algorithm as the core, by calculating the amplitudes of 8 frequencies, key assignments is determined.After tested, the system can achieve the requirements of the synthesis and recognition of DTMF signals.