PHASE ESTIMATION BY BISPECTRUM - A GROUP DELAY APPROACH

In this paper, a new method of extracting the system phase from that of the bispectrum, based on a group delay approach has been proposed. The phase estimation is achieved by relating the bispectral phase to the system group delay function. The proposed method does not make any assumptions regarding the phase values at any of the frequencies, uses all the bispectral phase data, does not involve any solution of a system of equations and does not require any phase unwarping, It is applicable to moving average (MA), autoregressive (AR) and autoregressive moving average (ARMA) systems and not just limited to MA systems. Even with fewer triple correlation lags. its performance is either superior to or at par with those of Lii and Rosenblatt's method or Brillinger's method. The proposed method has been evaluated for ARMA systems.