输入信号为方波信号+高斯白噪声，方波信号基 频为1kHz，幅值为1，高斯白噪声方差为0.2， 均值为0，采样频率为20kHz。试用最大熵估计 法估计此信号的AR模型及其功率谱，并分析结 果-The input signal is a square wave signal+ Gaussian white noise, square wave signal fundamental frequency 1kHz, amplitude is a Gaussian white noise variance is 0.2, the mean is 0, the sampling frequency is 20kHz. Try maximum entropy estimation method to estimate the AR model of this signal and its power spectrum, and analyze the results