Abstract: An optical encoding system for determing the absolute and the incremental positions of a movable member relative to a stationary member. For example, three stationary light sources may be supported by the stationary member for emitting three narrow light beams on respective paths. An encoding band may be supported by the movable member in the paths of the light beams. The band has a timing and incremental encoding track comprising at least one series of alternating light-blocking stripes and light-passing stripes, and a data track comprising a series of distinct absolute position tags. A read head may be supported by the stationary member and has three optical sensors, one for each light beam, two preferably in quadrature with each other for the timing and incremental encoding track, and one for the data track. Each optical sensor includes light sensors for generating an analog signal voltage.

Abstract: An optical encoding system for determining the absolute position of a movable member relative to a stationary member. For example, a bar-code scanner may be supported by a stationary member for scanning bar-code symbols in its field of view. An encoding band may be supported by the movable member so that a portion of the band is scanned by the bar-code scanner. Affixed to or otherwise marked on the band is a sequential series of bar-code symbols, each symbol encoding the absolute position of its location on the band. A bar-code decoding system, actuated by the signals produced by the bar-code scanner, decodes the bar-code symbol scanned by the scanner, and determines the absolute position of a movable member relative to the stationary member.

Abstract: An optical encoding system for determining the absolute and the incremental positions of a movable member relative to a stationary member. For example, three stationary light sources may be supported by the stationary member for emitting three narrow light beams on respective paths. An encoding band may be supported by the movable member in the paths of the light beams. The band has a timing and incremental encoding track comprising at least one series of alternating light-blocking stripes and light-passing stripes, and a data track comprising a series of absolute position tags alternating with spacers, each tag being framed by start bits. A read head may be supported by the stationary member and has three optical sensors, one for each light beam, two preferably in quadrature with each other for the timing and incremental encoding track, and one for the data track. Each optical sensor includes light sensors for generating an analog signal voltage.