Parameter Estimation of Low-Frequency Signal with Negative Frequency Contribution
According to the problem that there is a decline in accuracy of low-frequency signal parameter estimation by using the algorithm of all-phase FFT, an improved phase difference correcting spectrum method based on all-phase FFT is proposed. The contribution of negative frequency to FFT calculation was considered while using phase difference correcting spectrum method. The all-phase FFT spectrum analysis theory was presented as well as a traditional phase difference correcting method based on it. The equations of parameter estimation such as frequency, amplitude and phase for low-frequency signals were derived with the negative frequency contribution to spectrum analysis. The simulation results show that the method proposed in this paper can be used to estimate the parameters of low-frequency signals in a high accuracy, and also achieves an improvement in anti-noise ability.