The Parameter Estimation Algorithms Research For Sinusoidal Signal Under Strong Noise Background Based On Wavelet Transform

In the field of communication and signal processing, weak sinusoidal signal parameter estimation is a basic question, which is studied by many researchers. Currently, the parameter estimation of weak sinusoid signal has been widely applied to the signal recovery, speech signal processing, radar target positioning, and many other fields. Therefore, the research on weak sine signal parameter estimation has important theoretical significance and practical value.The DFT algorithm and the least square algorithm are analyzed in this paper, when the signal is weak, the gap between the estimate parameter and the real value is relatively large.To solve this problem, we improved the DFT algorithm and the least square method, obtained a sine signal frequency estimation algorithm based on DFT and DWT, a phase estimation method based DWT, and an improved amplitude iterative algorithm. In this paper, the main work is as follows:1. An improved algorithm based on DFT frequency estimation is presented .The algorithm enhances the precision of frequency estimation, the derivation is simple, at the same time the calculation capacity of the improved algorithm is lower than the DFT algorithm,and it is easy for engineering application.2. The frequency estimation algorithm and the iterative algorithm for frequency correction are given according to the discrete wavelet transform. Using the wavelet transform we preprocess the signal, when 2 new sequences with different length constructed,then make Fourier transform to each of the sequences and finally by the deduction the rough estimate frequency is obtained. Based on this, the iterative algorithms of corrective frequency is given,and its property is analyzed;3. The estimation algorithm of phase is given according to the discrete wavelet transform.First, we preprocess the weak sampled signal using the wavelet transform, and constructs 2 new sequences with different length, make Z-transform to the new sequence, then combined with the way of construction, by the deduction, the estimate value of amplitude and phase are obtained. The simulation results show that this algorithm has higher accuracy than the past parameter estimation algorithm under low signal-to-noise ratio;4. Sine signal amplitude estimation algorithm is given. And though the simulation, we compared this amplitude estimation algorithm with the algorithm based on autocorrelation function,the results show that this algorithm has a higher estimation precision.