摘要
通过分析分数阶Fourier变换功率谱与信号相位微分的关系,提出了根据信号密度分布和分数阶Fourier谱估计信号瞬时频率的方法,并对含噪声和不含噪声的两种信号进行了计算机仿真。仿真结果表明了其有效性。该方法适用于信噪比大于3dB的信号。该方法采用非递归算法,不需要进行时频平面上的投影和峰值搜索,运算量低。
According to the relationship between the fractional Fourier power spectrum and signal＇s phase differentiation operation, a novel method for solving the instantaneous frequency estimation problem from only intensity distributions and the fractional Fourier spectrum is proposed. The efficiency of the method is demonstrated on two examples including signals with and without noise. It is shown that the proposed method works well for signal-to-noise ratios （SNRs） higher than about 3dB. The proposed method is noniterative and doesn＇t need projection or peak-searching, thus it takes low computing cost.
关键词
分数阶FOURIER变换
瞬时频率估计
相位重构
fractional Fourier transform
instantaneous frequency estimation
phase reconstruction
