Blind indentifiability of a band-limited nonminimum phase system from its output autocorrelation

The authors address the problem of blind identification of a band-limited nonminimum-phase channel from its output autocorrelation when the input is a discrete-time white noise sequence. It has been well established in the literature that when the input to a linear-time-invariant (LTI) channel (system) is a continuous-time white noise, the identification of the phase of the channel from its output autocorrelation is impossible. To make the channel identification from its output autocorrelation unique, it is necessary to know a priori the whole phase response of the channel. It is shown that when the input is a discrete-time white noise sequence, what is needed to make the channel identification from its output autocorrelation unique is reduced to the phase response in the frequency range of -1/2T>