Utilizing a ring shaped transducer with a 7 inch clear-through center hole this new Microgon shaft encoding system has achieved a standard deviation accuracy of 0.26 seconds of arc when operated at a resolution of 221 or 2,097,152 counts per turn. The ring-type transducer is suitable for radar on-axis installations with waveguides passing through the center. Other applications include rate tables and tracking instrument mounts. This Micro gon system comprised of a transducer, transducer controls, dual preamplifiers, and one box of transistorized electronics has been developed for natural binary or 8, 4, 2, 1 coded decimal outputs of digit and complement with visual displays. Two of these systems are in use on ADVENT radar antennas.
David W. Comstock,
"A New Digital Microgonlometer Shaft Encoding System for High acy Resolution and High Aor Applications," Optical Engineering 1(3), 010380 (1 March 1963). https://doi.org/10.1117/12.7971258