两种高精度FFT算法在介损测量中的应用

Application of two high-accuracy FFT algorithms to measure dielectric loss

直接采用基于FFT的谐波分析法进行介损测量时,采样的非同步性使测量精度大大降低。为了减小频率波动引起的非同步采样对傅立叶变换的影响,提高介损的测量精度,通过加窗插值和修正理想频率对原算法进行了改进。先对非同步采样的泄漏效应进行了简要的分析,然后就提出的两种改进算法在介损测量中的应用进行了详尽论述,理论推导表明二者都能很好地满足介损的精度要求。最后借助MATLAB软件进行了数值仿真,仿真结果进一步验证了改进算法的有效性和可行性。

When harmonic analysis approach based on FFT algorithm is directly applied to measure the dielectric loss, the accuracy of themeasurement will be greatly decreased because of the asynchronous sampling. To reduce the influence of an asynchronous sampling sequence caused by frequency fluctuation on FFT and to improve the precision of dielectric loss measuring, this paper brought about the interpolation algorithm on Harris window and the algorithm ofmodifying frequency. The leakage problem of FFT is analyzed and the two improving algorithms applied to measure dielectric loss are discussed. The accurate dielectric loss can be obtained through the new algorithm. The validity and feasibility are proved through numerical simulation.