Synaptics Incorporated
Input sensing using code division multiplexing (CDM)

Abstract:

Sensing systems and methods that utilize lower-order zero row sum code division multiplexing (CDM) drive matrices to reduce or eliminate radiative emissions. Measurements corresponding to an input received at a sensing region of the input device are obtained by separately driving multiple subsets of transmitters of the input device, and obtaining measurement values corresponding to each separately-driven subset of transmitters via the receivers, wherein a plurality of measurement iterations are performed for each separately-driven subset of transmitters, the plurality of measurement iterations corresponding to a zero row sum CDM drive matrix for the separately-driven subsets of transmitters. An image of the input is generated based on the obtained measurements.