修正自适应Chirplet分解法及其快速实现
doi: 10.3724/SP.J.1146.2006.00189
Modified Adaptive Chirplet Decomposition and Its Fast Implementation
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摘要: 为克服时频关系为线性的基函数的不足，该文提出一种新的信号分解算法修正自适应Chirplet分解法，将Chirplet基函数推广到三次相位信号的形式，因此可以逼近信号中的非线性时变结构成分。同时提出了一种快速分解算法，该算法通过计算信号的三次相位函数，可得到其能量分布集中于信号的瞬时频率变化率曲线上的结论，此时通过谱峰检测可同时获得基函数的二、三次相位系数，时间中心以及幅度的估计；进而通过解调频技术获得其初始频率和时间宽度的估计。文中给出了实现该方法的具体步骤，并分别以仿真信号和蝙蝠回声定位信号为例验证了该算法的有效性。Abstract: A new algorithm of signal decompositionModified Adaptive Chirplet Decomposition(MACD) is presented to overcome the deficiency of basis functions with linear time-frequency relations. The chirplet atom is extended to quadratic frequency modulated signal, and it can approach the nonlinear time varying components of the original signal. At the same time, a fast algorithm is presented by computing the Cubic Phase (CP) function of the signal, it is shown that the CP function is concentrated along the instantaneous frequency rate, and the peak of the CP function yields the estimates of the coefficients of quadratic and cubic phase, the time center and the amplitude, Then the initial frequency and the time extent can be obtained by the dechirp technique. The scheme of the algorithm is shown in this paper, and the results of simulated data and echolocation signal from brown bat demonstrate the validity of the method proposed.
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