The distortion compensation apparatus includes: a branching unit to branch
a part of the output signal of an amplifier to a signal path to a
distortion compensating unit; a switch to pass the output signal of the
amplifier to the interference or branching unit; and a controlling unit
to control an amount of the compensation of the distortion under a
pass-permitted state in which the switch passes the output signal in
response to a result of measurement of a signal transmitted through the
signal path under a state where the switch is in an interruption state.