Absolute encoder using multiphase analog signals
Patent 5506579 Issued on April 9, 1996. Estimated Expiration Date: 
April 9, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 9, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesPosition encoder Absolute encoder Interpolation method and shaft angle encoder Absolute position encoder Position detection encoder having plural light receiving and light emitting elements Position encoder using a pseudo-random coding sequence Patent #: 5173693 InventorAssigneeApplicationNo. 711034 filed on 06/06/1991US Classes:341/11, Incremental250/231.18, Position indicating shaft encoders with means to generate a unique signal for each specific angular shaft position341/13OpticalExaminersPrimary: Williams, Howard L.Attorney, Agent or FirmInternational ClassH03M 001/30AbstractThe absolute encoder utilizes two or more sensors per track and the output of each sensor is modulated by the track to generate a multiphase analog signal from each track. An analog to digital converter converts each analog signal to a digital value. The multiphase cyclic digital values are combined into a single linear output per track that increases linearly from zero to a maximum over the full span of the measuring scale. Corrections are made for zero drift in the analog signals, for changes in amplitude (gain) of the analog signals and for deviations in the linear values from a perfect straight line. When measuring rotary displacement the methods disclosed may be used to combine the outputs of the geared scales.Field of SearchReal and complementary patternsHaving combined (e.g., denominational, combination code) coding pattern Constant distance code Incremental Optical Magnetic, inductive or capacitive Brush and contacts or conductive pattern Position indicating shaft encoders with means to generate a unique signal for each specific angular shaft position With means to indicate a complete shaft rotation Using phase difference of output signals from plural photodetectors Incremental shaft readers; i.e., with means to generate increments of angular shaft rotation | |
