Formulation of the Rate-distortion association is an information-theoretic study in the field of
signal encoding systems. Since a more general approach to model the nonstationarity exhibited
by real-world signals is to use appropriately fitted time varying autoregressive (TVAR) models,
we have investigated the rate-distortion function R(D) for the class of time varying
nonstationary signals. In this study, we present formulations of the rate-distortion function for
the Gaussian TVAR processes. The R(D) function can serve as an information-theoretic bound
on the performance achievable by source encoding techniques when the processing signal is
represented exclusively by a Gaussian TVAR model.