Tuning algorithm for noise reduction in an active stylus

摘要

In one embodiment, a stylus receives a signal, the stylus being able to wirelessly transmit signals to and receive signals from a device, and the stylus having a plurality of electrodes disposed in a tip of the stylus. The stylus compares a first value of the signal to a first threshold and determines whether to start a timing period based at least in part on this comparison. If the timing period is started, the stylus compares a second value of the signal to a second threshold and determines whether to stop the timing period based at least in part on this second comparison. If the timing period is stopped, the stylus determines whether the duration of the timing period is within a pre-determined range of timing period values. If so, the stylus processes the signal.

主权项

1. A method comprising:
receiving a signal at a stylus, the stylus being operable to wirelessly transmit signals to and receive signals from a device, the stylus comprising a plurality of electrodes disposed in a tip of the stylus; calculating, based at least in part on a first value of the signal and a second value of the signal, a first average value of the signal; comparing the first average value of the signal to a first threshold; determining whether to start a timing period based at least in part on comparing the first average value of the signal to the first threshold; if the timing period is started:
calculating, based at least in part on a third value of the signal and a fourth value of the signal, a second average value of the signal;comparing the second average value of the signal to a second threshold;determining whether to stop the timing period based at least in part on comparing the second average value of the signal to the second threshold;if the timing period is stopped:
determining whether a duration of the timing period is within a pre-determined range of timing period values; andprocessing the signal if the duration of the timing period is within the pre-determined range of timing period values.