An Interpolation-Based Frequency Estimator Synthetic Approach for Sinusoid Wave

In view of the existing characteristics that the frequency estimator precision of Rife algorithm and Rife-based improved algorithm have a notable decline when SNR is lower, a new synthetic frequency estimator approach based on interpolation (NSAI) is presented, which integrates both zoom-FFT technology and Rife-based interpolation. The zoom-FFT and interpolation are employed to complement each other by the new estimator of NSAI to improve the precision of frequency estimation and immunity in noise. The simulation results indicate that NSAI not only has an estimation precision of approach CRB (Cramer-Rao lower bound) under the condition of low SNR, but also has a good stability in all frequency domains. The new estimator of NSAI needs only once FFT and two points DFT, therefore it can be achieved in real-time.