Goertzel算法是DTMF信号检测的核心，它利用二极点的IIR滤波器计算离散傅立叶变换值，快速有效的提取输入信号的频谱信息。-Goertzel algorithm algorithm is DTMF signal detection at the core, It uses two poles of the IIR filter calculating the discrete Fourier transform value rapid and effective extraction of