估算带宽:计算输入信号的单边功率谱密度（ESD）；计算相对于特定值的ESD的最高和最低频率。-Estimation of bandwidth: Calculate the input signal

非归零型差分相位调制信号建模与仿真分析 ，计算目标和海洋回波的功率谱密度,在MATLAB中求图像纹理特征。- NRZ type differential phase modulation signal modeling and simulation analysis, Calculating a target and ocean echo power spectral density, In the MATLAB image texture feature.