초록 ▼

An optical code disc includes a fine track which provides a high resolution signal, at least one V scan natural binary track synchronized to the fine track by lead and lag detectors, and Gray code tracks which provide the most significant bits of the digital output of the encoder system. The number

An optical code disc includes a fine track which provides a high resolution signal, at least one V scan natural binary track synchronized to the fine track by lead and lag detectors, and Gray code tracks which provide the most significant bits of the digital output of the encoder system. The number of circuit elements in the multiplier circuitry associated with the fine track are reduced by means of a quadrant switching technique whereby the sinusoidal inputs to the multiplier are repeated through each quadrant of the fine track cycle. The V scan and Gray code tracks are optically multiplexed to reduce the number of leads from the optical detector. The use of both V scan and Gray code tracks minimizes the number of detectors required in the system while maintaining large detector signals from each track. The V scan and Gray code outputs are synchronized by the use of an overlapping bit.

대표청구항 ▼

An optical angular encoder system including a code disc having a fine code track thereon, illuminating means for illuminating the code track, detecting means for detecting the illumination which passes through the code track and for providing sinusoidal detector outputs as a function of the angular

An optical angular encoder system including a code disc having a fine code track thereon, illuminating means for illuminating the code track, detecting means for detecting the illumination which passes through the code track and for providing sinusoidal detector outputs as a function of the angular position of the code disc, and multiplier circuitry for providing a multibit digital output from the sinusoidal outputs by deriving a family of phase shifted sinusoids in parallel circuits, converting the family of sinusoids to squarewaves and logically combining the squarewaves from parallel circuits, the system characterized by: the multiplier circuitry being designed to provide a multibit digital output directly from the sinusoidal detector outputs only through one of a plurality of segments of the fine track cycle; and circuitry for selectively modifying the sinusoidal inputs to the multiplier circuitry such that those inputs are identical through each of said segments of the fine track cycle.