Precise analytical asymptotic exponential rates of error, and bounds o
n those rates, for differential multiple-phase-shift keying (DMPSK) sy
stems that include post-detection integration are provided. Easily com
puted bounds on these rates are provided, both in the case of floor bi
t error probability (i.e., with no additive noise) and in the case of
weak additive noise. The derivation uses the theory of large deviation
s and illustrates its applicability to the analysts of communications
systems.