传统离散傅里叶变换(DFT)算法因其具有计算效率高,便于在嵌入式系统中应用的优点而广泛应用于谐波检测中,但其在非同步采样下,频谱泄露和栅栏效应的存在将会影响到测量结果的精确性.将扩展傅里叶变换(EDFT)应用于谐波检测中,EDFT以傅里叶积分变换为目标,在扩展的频率范围内优化变换基即利用变换基函数取代传统DFT变换中的指数基来构造信号的目标函数,并将原始数据通过迭代近似拟合从而使测量精度得以提高.经验证,在非同步采样和噪声存在的条件下,该方法依然有较高的频率分辨率和较强的抗干扰特性,适用于高精度测量或检测.%The traditional discrete Fourier transform(DFT)algorithm has fast computational efficiency and is convenient to apply to the embedded system,which is widely used in the harmonic detection. However,the available spectrum leakage and picket fence effect may influence the accuracy of the measuring result under the condition of asynchronous sampling. The extended discrete Fourier transform (EDFT) algorithm is applied to the harmonic detection. Taking the Fourier integral transform as the target of EDFT algorithm,the transform basis is optimized within the extended frequency range,for which the index basis in tra-ditional DFT is replaced by the transform basis function to construct the target function of the signal. The original data is carried out with the iterative approximation fitting to improve the measuring accuracy. The simulation result shows that,under the condi-tions of asynchronous sampling and noise,the algorithm has high frequency resolution and strong anti-interference ability,and is suitable for the high-precision measurement or detection.
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