The ability to simultaneously stimulate and record from neural tissue is paramount to the creation of a feedback-enabled control system. This stimulation creates additional electrical potential as seen by the recording system. This artifact can be approximated by a linear transfer function of the stimulus current. The computation of the transfer function is complicated by measurement noise and the bias and variance inherent in spectral estimation. We reduce bias and variance by using multi-taper techniques. We demonstrate the use of this transfer function as a method to remove stimulation artifact in the context of neural modulation with applied low-frequency (<< 100 Hz) electric fields in chronically instrumented animals.