in the "bandwidth-limited regime" (formula_28, "i.e." the domain of non-binary signaling), the effective coding gain formula_2 of a signal set formula_3 at a given target error rate formula_31 is defined as the difference in db between the formula_32 required to achieve the target formula_31 with formula_3 and the formula_32 required to achieve the target formula_31 with m-pam or (m×m)-qam ("i.e." no coding). the nominal coding gain formula_10 is defined as