精确估计双音多频信号的频率 ◆通过不同窗函数，画语图分析双音多频信号 ◆估计各个时段的频率，频谱分辨率要求≤10Hz（含戈泽尔算法） ◆检测信号包含的电话号码信息 -Accurate estimation of the frequency of a dual tone multi frequency signal. ◆Through different window functions, the picture is drawn to analyze the dual ton