基于FFT系数的正弦信号频率估计算法.pdfVIP

第28 卷第6 期 光电技术应用 Vol.28 ，No.6 2013 年12月 ELECTRO-OPTIC TECHNOLOGY APPLICATION December ，2013 ·信号与信息处理· 基于FFT 系数的正弦信号频率估计算法 侯盼卫，杨 录，王建军 (中北大学电子测试技术国家重点实验室，山西 太原 030051) 摘 要：针对基于FFT 系数实部的频率插值算法在峰值谱线相位接近于±π/2 时频率估计误差较大的问题，提出了一种改进 的正弦信号频率估计算法。该算法首先利用FFT 系数的实部和虚部序列索引出峰值谱线位置，然后根据峰值谱线的相位，选取 实部与虚部序列中幅度较大的序列进行频率插值。仿真结果表明：在信噪比为3 dB、采样点为128 的情况下，整个频段上归一化 频率估计误差均方根小于0.02 ，接近Cramer Rao 下限，整体性能优于基于FFT 系数实部的频率插值算法和Rife 算法。改进的算法 频率估计精度高，计算量小，易于硬件实现。 关键词：频率估计；正弦信号；快速傅里叶变换；比值校正法 中图分类号：TN911.6 文献标识码：A 文章编号：1673-1255（2013 ）-06-0058-05 FrequencyEstimationAlgorithmofSineSignalBasedonFFTCoefficient HOU Pan-wei, YANG Lu, WANG Jian-jun (National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan 030051, China) Abstract:Larger frequency estimation error will appear when a peak spectrum line phase is closed to / 2 using frequency interpolation algorithm based on the real part of fast Fourier transform (FFT) coefficient. So an improved sine signal frequency estimation algorithm is proposed. The postion of peak spectrum line is firstly indexed by using the real part and imaginary part sequence of FFT coefficient. And then according to the phase of peak spectrum line, the se⁃ quences with larger amplitude in real and imaginary part sequences are selected to participate in frequency interpolation. Simulation results show that at the condition of SNR=3 dB and sampling number N=128, the root mean square of normalized frequency estimation error at the whole frequency band is less than 0.02 and closed to Cramer-Rao lower bound (CRB). The total performance of the improved algorithm is better than the frequency interpolation and Rife al⁃ gorithm based on the real part of FFT coefficient. The im