Aliasing effects in sampling spectrally correlated processes

The problem of sampling continuous-time spectrally correlated (SC) processes is addressed. SC processes have Loève bifrequency spectrum with spectral masses concentrated on a countable set of support curves. This class of nonstationary processes extends that of the almost-cyclostationary processes and occurs in wide-band mobile communications. The class of the discrete-time SC processes is introduced and characterized. It is shown that such processes can be obtained by uniformly sampling the continuous-time SC processes. Sampling theorems are presented and a sufficient condition to avoid aliasing in the whole bifrequency domain is provided.