  It has been pointed out that for some types of measurement the Heisenberg
uncertainty relation seems to be violated. In order to save the situation a new
uncertainty relation was proposed by Ozawa. Here we introduce revised
definitions of error and disturbance taking into account the gain associated
with generalized measurement interactions. With these new definitions, the
validity of the Heisenberg inequality is recovered for continuous linear
measurement interactions. We also examine the changes in distribution functions
caused by the general measurement interaction and clarify the physical meanings
of infinitely large errors and disturbances.
