An overview of aliasing errors in discrete-time formulations of time-frequency representations

Recent discrete-time time-frequency representation (TFR) algorithms claim t o provide alias-free approximations to their continuous-time TFR counterpar ts without requiring oversampling of the signal. By counterexamples, we dem onstrate that some of these claims are invalid. We give new necessary condi tions for reducing aliasing errors in these discrete-time TFR algorithms.