研究了一种改进的相位展开算法及其在瞬时频率估计中的应用.首先讨论了噪声对相位展开的影响,发现当每个周期内的样本数为2个样本时相位展开具有最佳的性能;接着利用这个性质得到一种简单的相位展开算法,可以在较低信噪比条件下估计出信号的瞬时相位;随后把相位展开算法应用于正弦波频率估计,得到了改进的相位平均法,利用它可以在较低信噪比条件下得到宽带信号的瞬时频率曲线;最后通过MATLAB仿真对算法进行验证.%An improved phase unwrapping algorithm and its application to instantaneous frequency estimation is investigated. Firstly the influence of noise on phase unwrapping is discussed. It is observed that when the signal is sampled at two sample per cycle,the phase unwrapping has the best performance.Consequently,an improved phase unwrapping algorithm is obtained, which can be used to estimate the instantaneous phase of signals at low signal-to-noise ratios (SNR). Consequently, the new phase unwrapping algorithm was applied to the frequency estimation of a sinusoid and an improved frequency estimator was proposed. The frequency estimator can be utilized to estimate the instantaneous frequency of wideband signals at low signal-to-noise ratios. The simulation results show that the performance of the new instantaneous frequency estimator is better than previous algorithms.
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