The Region of Convergence for the $z$-Transform

Much of the power of the $z$-transform is due to the fact that it exists for signals that have no DTFT. In this lesson you will learn how the region of convergence defines the range of values $z$ for which the $z$-transform converges. The region of convergence differentiates causal from non causal signals and indicates whether a causal system is also stable, concepts that are further explored in subsequent lessons.