说明：  对建立的AR模型，利用Levinson-Durbin递归公式计算了模型参数，对输入信号的功率谱密度进行了估计，并绘制了信号的时域图和功率谱图。
(For the established AR model, the Levinson-Durbin recursive formula is used to calculate the model parameters, and the power spectral density of the input signal is estimated, and the time domain and power spectrum of the signal are plotted.)