用AR模型估计信号的功率谱的仿真:分别用svd-TLS的方法，4阶AR模型，100阶AR模型仿真信号-With the AR model to estimate the power spectrum of the simulation: each method of using svd-TLS, 4-order AR model, AR model order of 100 simulated signal

该函数用来计算任意函数的一阶偏导数(数值方法),用平面波展开法计算二维声子晶体带隙,基于互功率谱的时延估计。- This function is used to calculate the arbitrary function of the first order partial derivative (numerical methods), Computation Method D phononic bandgap plane wave, Based on the time delay est

数学方法是部分子空间法，基于互功率谱的时延估计，大学数值分析算法。- Mathematics is part of the subspace, Based on the time delay es