An Amplitude and Phase Regulating Magnetic Field Generator for an Eye Movement Monitor

One common method of eye movement detection uses an ocular search coil within two magnetic fields arranged in spatial and temporal quadrature. An inexpensive circuit is presented that regulates the strength of the two fields and their phase separation. This stabilization minimizes perturbations due to motion of the field's generating coils, motion of metal witiin or near the fi'elds, and component value drift.