  A measurement scheme to perform a repeatable phase detection on a two-mode
field is presented. The interaction with the probe state (the output state of a
phase-insensitive high-gain amplifier) is described by a Hamiltonian which is
physically realizable in the rotating wave approximation. Information on the
system is obtained through unconventional heterodyne measurements performed on
the probe field after the interaction with the system. The expressions for the
probability distribution and the state reduction are given.
