The paper presents some results of studies of properties of ensemble averages of Wigner time-frequency distributions (WDs) of stationary and nonstationary Gaussian random processes and of radio-frequency telecommunication signals (PSK and FSK). For a real random process, the WD is a sum of an even term WD even  and a cros-term WD cross . In selected cases, the theoretical forms of ensemble averages of these terms are derived and compared with results of computer simulations. For proper processes, ensemble averages E{W cross (t, f)} are cancelled. In computer simulations, their level decreases considerably with increasing number of sample functions. In other cases, E{W cross (t, f)} carries an information about some properties of a random process.
['Kajetana M. Snopek']
Wigner distributions of noise and telecommunication stochastic processes