First is to compare actual value to the calculated, and second is analysis of the effect on harmonic wave. Take Fast Fourier Transform Algorithm to the samples fore-and-aft integral, and compare the amplitude and angle.

• 首先是直接比较实际值与还原值，其次是分析各种算法对谐波的影响：分别对积分前后的采样值进行快速傅立叶变换，比较各次谐波幅值和相位的变化。