According to voltage crossing points algorithm measurement frequency,Interpolating new sampling series from original fixed sampling series by the linear Lagrange interpolation algorithm.

• 结合电压过零点测频法测得的频率,对原固定采样频率下的采样序列采用拉格朗日线性插值法抽取新的采样序列,最终利用傅氏算法测得高精度频率。