Patent ID: 6946648

Claim:
A system for accurately sensing and determining the position of a uniformly rotating shaft characterized in using a single marker in tandem with a high frequency signal, said system comprising: a shaft mounted with a disc having a single marker; an opto-electronic device placed in front of the disc for generating a marker signal for every rotation of the disc; a means for producing a high frequency signal for sampling/slicing/slotting the time period between two consecutive marker signals; input terminals of a gating mechanism being connected to the opto-electronic device and the high frequency signal generator; an output terminal being connected to a counter such that the gating mechanism allows the high frequency signal to pass to the counter, said counter being configured for counting the number of pulses in the high frequency signal; a D/A converter connected to an output of the counter for converting the number of pulses counted into an analog signal; and a display mechanism for displaying the analog signal in terms of the angle through which the shaft has rotated.