Noise are one of the main reasons for biased frequency estimation of ANF (Adaptive Notch Filter). Noise will greatly affect the performance of ANF frequency estimation method under low SNR. When analyzing the ANF statistical performance

some linear approximation methods for ANF transfer function will degrade

the performance of ANF frequency estimation method cannot be evaluated precisely. So the noise statistical performances of mean and variance after different transform are analyzed by using correlation function and power spectrum method. Noise statistical performance results are used for performance analysis of ANF frequency estimation method

meanwhile a theoretical analysis foundation is established to improve the accuracy of ANF frequency estimation method. The performances of ANF frequency estimation method are compared by the theoretical values and the actual values

which show the effectiveness of the noise analysis method

and the steady-state performance of frequency estimation can be estimated approximately.