说明：  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。试用周期图法和 ARMA谱估计法(SVD-TLS)估计此信号的功率 谱，并分析比较其结果
(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 periodogram and ARMA spectral estimation method (SVD-TLS) estimate the power spectrum of this signal, and the analysis and comparison of the results)