  Radio astronomy is vulnerable to interference from a variety of anthropogenic
sources. Among the many strategies for mitigation of this interference is
coherent time-domain canceling (CTC), which ideally allows one to "look
through" interference, as opposed to avoiding the interference or deleting the
afflicted data. However, CTC is difficult to implement, not well understood,
and at present this strategy is not in regular use at any major radio
telescope. This paper presents a review of CTC including a new comprehensive
study of the capabilities and limitations of CTC using metrics relevant to
radio astronomy, including fraction of interference power removed and increase
in noise. This work is motivated by the emergence of a new generation of
communications systems which pose a significantly increased threat to radio
astronomy and which may overwhelm mitigation methods now in place.
