Patent ID: 6538640
Filing Date: 2003-03-25
Classification: G06F

Abstract:
A method for detecting movement of a pointing device, comprising the steps of:(a) producing a pair of signals by monitoring rotation of a rotating element in the pointing device at two spaced-apart points, a phase relationship of said pair of signals changing state so as to indicate a speed and a direction at which the pointing device is moving relative to an axis; (b) sampling the state of the pair of signals, producing a plurality of samples; and (c) processing the plurality of samples to produce an output signal indicating the direction and the movement of the pointing device as a function of a change of the state of the pair of signals, said step of processing further including the steps of: (i) determining that a change in state has not been sampled and has thus been skipped; and (ii) upon determining that a state has been skipped, adjusting the output signal to include movement of the pointing device for the state that was skipped.