US Patent 9483129 Active stylus with fractional clock-cycle timing

In one embodiment, a method performed by an active stylus includes wirelessly receiving a synchronization signal from a touch controller. The method also includes determining a synchronization parameter of the synchronization signal, the synchronization parameter including an integer part and a fractional part, the integer part representing a positive integer multiple of an active-stylus clock period and the fractional part representing a fractional portion of the active-stylus clock period. The method further includes wirelessly transmitting information for reception by the touch controller, where the information includes a series of data portions, a successive data portion in the series being separated from a preceding data portion by a time interval. The time interval is based at least in part on the active-stylus clock period, the integer part of the synchronization parameter, and an updated fractional error value.