A processing system for an input device comprises sensor circuitry. The sensor circuitry is configured to operate sensor electrodes for input sensing during a first sensing frame. During a first period of the first sensing frame the sensor circuitry is configured to drive a first portion of the sensor electrodes with a sensing signal, drive a second portion of the sensor electrodes with a guarding signal, and drive a third portion of the sensor electrodes with a reference signal. The guarding signal and the sensing signal have at least one characteristic in common selected from the group consisting of amplitude, phase and frequency. The third portion of the sensor electrodes overlaps a first gate line of a display panel selected for updating during the first period.