  I discuss the process of measurement in the context of a communication
system. The setting is a transmitter which encodes some physical object and
sends it off, a receiver which measures some property of the transmitted
physical object (TPO) in order to get some information, and some path between
the transmitter and the receiver over which the TPO is sent. The object of the
game here is to characterize the TPO, either as an end in itself (research), or
to examine its potential for information transmittal (communication). If the
TPO is a 'small' object then quantum mechanics is needed to play this game. In
the course of this work, I hope to broaden the concept of measurement in
quantum mechanics to include noisy measurements and incomplete measurements. I
suggest that quantum density operators are logically associated with the
transmitter and some portion of the path, and that quantum measurement
operators are logically associated with the rest of the path and the receiver.
Communication involves the overlap of a density operator and a measurement
operator. That is, the fundamental conditional probability of the communication
process is given by the trace of the product of a density operator and a
measurement operator.
