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 minimum 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. A laser reflection technique was used to accurately calibrate the instrument parameters. A statistical behavioral technique is described which is routinely used to calibrate the search coil implanted in the animal. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.