Harmonic Retrieval in Complex Noise Based on Group Delay

Group delay (GD), the negative derivative of Fourier Transform phase, is regarded as a good tool for spectral estimation in additive noise, for its sharp peak and high resolution. However, as far, GD has not been utilized in the case involving complex noises. In this paper, a novel GD is proposed to the time-varying cumulants of harmonics in complex noises, termed as CGD. A simple and practical algorithm is also derived. Numerical results show that, for the problems in complex noises, the new approach outperforms some traditional methods greatly.