Patent ID: 8481872

Claim:
A method for operating a digitizer with an autonomous stylus, the method comprising: autonomously transmitting a signal burst at a defined rate by a stylus in accordance with a transmission repeat cycle of the stylus, wherein the transmission repeat cycle of the stylus is asynchronous with a refresh cycle of a digitizer and wherein the duration of the transmission repeat cycle is predefined and known to the digitizer; sampling outputs of a digitizer sensor, wherein the digitizer sensor is sampled over a plurality of chunk sampling periods, wherein the plurality of chunk sampling periods are sampling periods separated by periods wherein the digitizer sensor is not sampled, and wherein positioning of each of the plurality of chunk sampling periods is staggered with respect to the refresh cycle of the digitizer; determining one chunk sampling period over which a signal burst transmitted from the stylus is detected; determining a timing of signal bursts transmitted by the stylus over subsequent refresh cycles based on subsequent output sampled in a corresponding time vicinity of the one chunk sampling period at times responsive to the duration of the transmission repeat cycle; and synchronizing the refresh cycle of the digitizer with the transmission repeat cycle of the stylus in accordance with the timing of the signal bursts.