中文说明：通过给出的随机过程，该随机过程是由3个实正弦信号组成，归一化频率分别为0.1,0.25,0.27，其中相位是相互独立在【0,2*pi】上分布的随机相位；噪声是均值为0、方差为1的实高斯白噪声，信噪比为30db,30db,27db,观测样本数为N，通过bartlett法，Welch法，周期图法计算随机过程的概率谱
English Description：
Through to out of random process, the random process is by 3 a real sine signal composition, return a of frequency respectively for 0.1,0.25,0.27, which phase is mutual independent in "0,2*pi" Shang distribution of random phase; noise is are value for 0, and variance for 1 of real Gaussian white noise, letter noise than for 30dB,30dB,27dB, observation sample number for n, through Bartlett method, Welch method, cycle figure method calculation random process of probability spectrum