The Use of Synchronous Demodulation for the Measurement of Eye Movements by Means of an Ocular Magnetic Search Coil

This paper describes an eye position monitoring system that can be built using inexpensive components for the demodulator. It uses a two-frequency (f and 2f) technique which provides excellent channel separation with a miinimum of adjustment and wide dynamic signal range. Phasing errors produce no crosstalk effects for a pure sine-wave signal. It should be noted that this system will also work as a single-frequency two-phase system, merely by changing the driver unit.