Welch法：Welch法对Bartlett法进行了两方面的修正：一是选择适当的窗函数w(n)，并在周期图计算前直接加进去，加窗的优点是无论什么样的窗函数均可使谱估计非负。二是在分段时,可使各段之间有重叠，这样会使方差减小。-Welch method: Welch method of Bartlett method amendments in two respects: First, select the appropriate window function w (n), and in the cycle before CALPHAD directly incorporated, plus the advantage of the window, no matter what kind of window function can be so spectral estimation of non-negative. Second, when in subparagraph can overlap between paragraphs, this would reduce the variance.