中文说明：现代信号处理中谱估计在matlab中的使用，相控阵天线的方向图（切比雪夫加权），进行逐步线性回归，小波包分析提取振动信号中的特征频率，正确率可以达到98％，该函数用来计算任意函数的一阶偏导数(数值方法)。
English Description：
Modern signal processing in spectrum estimation in MATLAB, phased array antenna directional diagram (Chebyshev weighted), stepwise linear regression, wavelet packet analysis and extraction of characteristic frequency in the vibration signal, correct rate can reach 98%, the function used to calculate any function of the first order partial derivative (numerical method).