Interference mitigation and clock dithering for a continuous-time receiver for capacitive sensing

• Main Authors: Lo, Steve Chikin, Shepelev, Petr
• Format: Patent
• Language: English
• Published: 08.01.2019
• Subjects: CALCULATING; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; PHYSICS

Embodiments herein describe input devices that include receivers for sampling capacitive sensing signals that perform continuous-time demodulation. An input device is provided that includes a plurality of sensor electrodes in a sensing region of the input device and a processing system coupled to the plurality of sensor electrodes and configured to generate a first measurement of a capacitive sensing signal acquired using a first sensor electrode of the plurality of sensor electrodes during a first time period, that comprises effects of a first modulated signal driven onto at least one of the plurality of sensor electrodes, the first measurement generated at a first sensing frequency based on a clock signal; periodically dither the clock signal; and adjust a demodulation frequency based on the dithered clock signal to generate a second measurement of the capacitive sensing signal during a second time period at the first sensing frequency based on the dithered clock signal.