基于幅值-相角判据的修正Rife正弦波频率估计算法
Modified Rife Algorithm for Frequency Estimation of Sinusoid Wave Based on Amplitude and Phase Criterion

机械工程领域普遍存在正弦信号, 为提高频率估计精度, 提出了一种基于幅值-相角判据的修正Rife算法, 即A-P-Rife算法．针对Rife算法接近两相邻量化频率中心区域时估计精度接近克拉美-罗限(CRLB)的性能特点, 对信号进行FFT变换得到幅值和相角并计算出频移因子．通过设定门限值, 对频移因子进行判断, 满足门限值的信号采用Rife算法进行估计, 不满足门限值的信号则采用相角判据进行估计, 以获得更高的估计精度．仿真结果表明：在频率估计性能上, 所提算法优于原始Rife算法、相角判据算法和M-Rife算法, 其与I-Rife算法性能接近, 但计算量小于I-Rife算法．修正Rife算法可有效提高频率估计精度, 降低误判率并减少计算量, 可应用于工程中的实时频率估计．
Sinusoidal signal is widely encountered in mechanical engineering. A modified algorithm called A-P-Rife algorithm is presented based on the amplitude and phase criterion to improve the estimation accuracy. The frequency estimation accuracy of Rife algorithm could reach Cramer-Rao lower bound(CRLB) when the signal frequency is close to the midpoint of two neighboring discrete frequencies. The amplitude and phase of the signal are obtained by the fast Fourier transform(FFT) in order to calculate the frequency-shifting operator. By setting a threshold value，the frequency-shifting operator is judged to determine which method to employ. If the frequency-shifting operator meets the threshold value，the signal is estimated by Rife algorithm; otherwise，it is estimated by phase criterion. The simulation results indicate that the new algorithm is superior to original Rife algorithm，phase criterion algorithm and M-Rife algorithm in frequency estimation performance，and has less computation than I-Rife algorithm with similar performance. The modified algorithm effectively improves the accuracy of frequency estimation and reduces misjudgment rate. It is proved that the new method can realize real-time frequency estimation of the signal