改进的DFT正弦信号频率估计  

A Modified DFT-based Frequency Estimator for Sinusoidal Signals

作　　者：高瑞令 吴晓富[1] 颜俊[1] 朱卫平[1] 

机构地区：[1]南京邮电大学通信与信息工程学院,江苏南京210003

出　　处：《信号处理》2014年第9期1071-1077,共7页Journal of Signal Processing

基　　金：国家自然科学基金(61372123;61302103;61372122);南京邮电大学科研基金(NY213002)

摘　　要：通过分析Candan算法和2N点DFT算法的性能,本文提出了一种改进的基于DFT的正弦信号频率估计算法。在对原始信号进行必要的离散化预处理后,在粗估计阶段利用Candan算法估计出频率偏差,利用该频偏对原始信号进行频率修正。然后对修正后的原始信号进行2N点DFT算法精估计。由于增加了对原始信号的频率修正步骤,该算法发挥了Candan算法和2N点DFT算法的优点,同时增加了算法的复杂度。仿真结果表明,在相对频偏为任意值时,改进算法频率估计的均方根误差均接近克拉美罗下限,并且估计性能优于现有的频率估计算法。In this paper, a fine resolution algorithm based on Discrete Fourier Transform （DFT） for frequency estimation of sinusoidal signals is proposed by combining the Candan algorithm with the 2N-point DFT algorithm. The proposed algorithm first employs the Candan algorithm to get a coarse estimate of the frequency, which is used to refine the incoming signal. The refined incoming signal is further input to the 2N-point DFF algorithm and a fine estimate of the possible residue frequency-offset can be well extracted. By taking the advantages of both algorithms, the proposed algorithm can perform better than either of the algorithms. The reason can be attributed to the additional frequency-offset step. As the proposed algorithm must run two component algorithms sequentially, it simply takes the sum of two individual algorithms in complexity. Simulation results show that the Root Mean Square Error （RMSE） of the proposed frequency estimator performs very close to the Cramer-Rao lower bound （CRLB）.

关 键 词：频率估计 Candan算法 2N点DFT算法 克拉美-罗下限 

分 类 号：TN911.7[电子电信—通信与信息系统]