In the paper the observer design problem is investigated in the context of
linear left shift invariant discrete behaviors, whose trajectories have sup
port on the positive axis. Observability and reconstructibility properties
of certain manifest variables from certain others, in the presence of laten
t variables, are defined and fully characterized. Necessary and sufficient
conditions for the existence of either a dead-beat or an exact observer are
introduced, and a complete parametrization of all dead-beat observers is g
iven. (C) 1999 Elsevier Science B.V. All rights reserved.