Synaptics Incorporated
Capacitive sensing active electromagnetic emission cancellation

Abstract:

An input device is disclosed that provides reduced electromagnetic emissions while detecting the presence of an input object. In one embodiment, a first set of sensor electrodes is driven with a first modulated signal while a second set of sensor electrodes is driven with a second set of modulated signals that is based on an inverted first modulated signal. The first set of sensor electrodes may determine a capacitance value while the second set of sensor electrodes may reduce electromagnetic emissions associated with the first set of sensor electrodes.