Accurate Frequency Estimation Based on Analytical Interpolated Discrete Time Fourier Transform
Yang Chao1, Li Bo1,2, Hu Xuquan1,3, Fu Zhihong1
1. State Key Laboratory of Power Transmission Equipment & System Security and New TechnologyChongqing University Chongqing 400044 China; 2. Electric Power Research Institute of Yunnan Power Grid Co. Ltd Kunming 650217 China; 3. Chongqing Triloop Prospecting Technology Co. Ltd Chongqing 402660 China
Abstract:When the cycles in record (CiR) of the signal is small, the spectral leakage from the image component is the main source of estimation errors in the frequency-domain interpolation. To eliminate the influence of spectral leakage and accurately estimate the frequency of a real sinusoidal signal with any CiR, an analytic interpolation algorithm based on generalized DTFT is proposed. The algorithm uses any DTFT spectral lines located in the main lobe of the spectrum to construct a linear equation set corresponding to the real and imaginary parts, and then an unbiased frequency estimator based on analytic interpolated DTFT is obtained. Besides, considering the influence of additive white noise in practice, a simple and effective iterative method is presented based on the analysis of the statistical characteristics of the frequency estimator. The iterative method ensures that the mean square errors (MSE) of the frequency estimation can consistently achieve the Cramer-Rao lower bound (CRLB) of the unbiased frequency estimation under any CiR. Simulation and experimental results confirm that the proposed algorithm is superior to other existing interpolated DFT algorithms.
杨超, 李波, 胡绪权, 付志红. 基于解析插值离散时间傅里叶变换的精确频率估计[J]. 电工技术学报, 2022, 37(6): 1338-1350.
Yang Chao, Li Bo, Hu Xuquan, Fu Zhihong. Accurate Frequency Estimation Based on Analytical Interpolated Discrete Time Fourier Transform. Transactions of China Electrotechnical Society, 2022, 37(6): 1338-1350.
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