Patent ID: 7834310
Filing Date: 2010-11-16
Classification: G01D

Abstract:
1. A method for processing an encoder's home position signal, comprising: generating an absolute home magnitude signal by modulating a plurality of bar widths on an encoder disk associated with a codewheel having a codewheel surface, wherein said codewheel surface rotates perpendicularly to an axis of rotation; generating a home pulse by rotating said codewheel one revolution, wherein said home pulse represents two consecutive momentary drops in said home magnitude; using an encoder reader to output a sine and cosine quadrature signal when said codewheel rotates perpendicularly to said axis of rotation; generating a rate of change signal by sampling said absolute home magnitude signal and filtering said rate of change signal in order to increase a signal-to-noise ratio; and determining a home position of said rate of change signal by applying a home position algorithm, wherein a signal characteristic shape of said rate of change signal increases the robustness of said home position associated with said rate of change signal in order to efficiently process said encoder home position signal and thereby enhance the effectiveness of a rendering device.