基于FPGA的DTMF信号的产生与检测

Generation and Detection of DTMF Signals Based on FPGA

文章以现场可编程门阵列(FPGA)为控制核心,设计并实现了双音多频信号(DTMF)的产生与检测,DTMF信号的产生是在FPGA内部将两个不同频率的正弦波形合成一个双频数字信号,通过D/A转换器变为模拟信号输出。DTMF信号的检测以Goertzel算法为核心,计算出8个频点的幅值,通过比较大小判断出相应的电话号码。经过工程测试,该设计能够达到DTMF信号的产生与检测要求,结果表明,将DTMF编解码算法集成于FPGA系统中,使DTMF信号系统变得简单灵活,充分发挥了FPGA的优势。

The generation and detection of Dual Tone Multi-Frequency （DTMF） signals are designed and implemented based on Field-Programmable gate （FPGA） which is taken as the kernel control chip. The DTMF signal is generated by converting a dual-frequency digital signal, which is composed of two sine signals with different frequencies in FPGA, to an analog signal through D/A converter. The detection of DTMF signals uses Goertzel algorithm, which calculates 8 frequency values and judges out the corresponding telephone numbers by comparing the values. By engineering test it is proved that the design can satisfy the requirements of generation and detection of DTMF signals. The result shows that the FPGA encoding and decoding operations integrated in FPGA system make the entire system simple and flexible, fully realizing the advantages of FPGA.