POWER SPECTRUM ESTIMATION OF COMPLEX SIGNALS AND ITS APPLICATION TO WIGNER-VILLE DISTRIBUTION - A GROUP DELAY APPROACH

In this paper, a method of estimating the power spectrum of a complex signal based on the Group Delay function (GD) is proposed and also app lied to the Wigner-Ville Distribution (WVD) to reduce the ripple effec t due to the truncation of the autocorrelation sequence. The proposed method is realised by the GD for a complex signal and the modified GD concept. This extends the performance advantages of the modified GD ap plicable to a real signal, to a complex one. Further, its application to WVD, reduces the truncation/ripple effect without sacrificing any f requency resolution, as no common window function is used. Significant improvement in performance, in terms of reduction in variance without any compromise on resolution and higher noise immunity, has been foun d over those of the periodogram and windowed WVD.