Radial optical encoder apparatus for shaft angle measurement

A radial optical encoder apparatus for shaft angle measurement comprising in combination:

• a shaft capable of rotation about its central axis, said shaft having a ring radially disposed thereon, said ring having a plurality of faceted surfaces disposed on it's outer surface parallel to said shaft central axis, said faceted surfaces being positioned in a predetermined pattern,
• a first optical encoder means positioned substantially perpendicular to said shaft, said first optical encoder means detecting angular rotation in said shaft position, said first optical encoder means converts said angular rotation into a pair of electrical output signals, said pair of electrical output signals being representative of said shaft position,
• a second optical encoder means positioned diametrically opposite said first optical encoder means, said second optical encoder means cooperating with said ring to provide a pair of auxiliary signals, and,
• an electronic processing means receiving said pair of electrical output signals and said pair of auxiliary signals, said electronic processing means decoding both pairs of input signals to provide three output signals.