A feedback compensation detector for a direct conversion transmitter includes a baseband processor, a direct up-converter, an antenna, and an impairment detection and compensation feedback circuit. The system and method evokes eyelid movement in the subject. A system comprises an origin node operable to distribute all of a plurality of descriptors of a MDC file to a first group of recipient nodes, wherein the origin node does not attempt to communicate all of the plurality of descriptors to all of the recipient nodes of the first group. The centering guide may optionally include a ring having one or more pins which firmly engage the cornea’s epiphilium. The first conductor thus serves as a heater and the second conductor as a heat diffuser. Each sector includes a first winding, first and second magnetic circuits and a saturation control assembly.