A Noniterative Frequency Estimator With Rational Combination of Three Spectrum Lines
A noniterative frequency estimator is proposed in this paper. The maximum bin of fast Fourier transform (FFT) is searched as a coarse estimation, then the rational combination of three spectrum lines (RCTSL) is used as the fine estimation. Based on least square approximation in frequency domain, the combinational weights of RCTSL are found to be constants depending only on data length, therefore the RCTSL is very computational efficient. Theoretical bound is also obtained, which shows the performance of RCTSL approaches the Cramér-Rao Bound (CRB). Simulation results demonstrate that RCTSL has a lower signal-to-noise ratio (SNR) threshold compared with other known estimators.