Let be a stochastic difference equation. Various relations between the input and output covariances and spectral densities are deduced under the hypotheses that is time dependent and that is a member of a nonstationary random process.
Keywords :
Autoregressive processes; Nonstationary stochastic processes; Autoregressive processes; Communications technology; Correlation; Difference equations; Information theory; Random variables; Signal detection; Statistics; Stochastic processes; Testing;