Reduced capacitive baseline shift via mixing period adjustments

A processing system comprising:

• a sensing module comprising sensing circuitry and configured to:
• drive, onto a first group of a plurality of sensor electrodes, a first capacitive sensing signal having a predefined first sensing frequency;
• acquire, based on the driven first capacitive sensing signal, first capacitive measurements of resulting signals received by a second group of the plurality of sensor electrodes, wherein acquiring first capacitive measurements comprises applying a first demodulation signal having a predefined first mixing period defined within a sensing period associated with the first sensing frequency;
• drive, onto a third group of the plurality of sensor electrodes, a second capacitive sensing signal having a second sensing frequency different than the first sensing frequency;
• and
• acquire, based on the driven second capacitive sensing signal, second capacitive measurements of resulting signals received by a fourth group of the plurality of sensor electrodes,
• wherein acquiring second capacitive measurements comprises applying a second demodulation signal having a predefined second mixing period within a sensing period associated with the second sensing frequency, the second mixing period different than the first mixing period, and
• wherein the second mixing period is selected such that a second average current value for the second capacitive measurements has a substantially linear relation to a first average current value for the first capacitive measurements, the linear relation based on the first sensing frequency and the second sensing frequency.

An input device comprising:

• a plurality of sensor electrodes;
• and
• a processing system coupled with the plurality of sensor electrodes, wherein the processing system is configured to:
• drive, onto a first group of a plurality of sensor electrodes, a first capacitive sensing signal having a predefined first sensing frequency;
• acquire, based on the driven first capacitive sensing signal, first capacitive measurements of resulting signals received by a second group of the plurality of sensor electrodes, wherein acquiring first capacitive measurements comprises applying a first demodulation signal having a predefined first mixing period defined within a sensing period associated with the first sensing frequency;
• drive, onto a third group of the plurality of sensor electrodes, a second capacitive sensing signal having a second sensing frequency different than the first sensing frequency;
• and
• acquire, based on the driven second capacitive sensing signal, second capacitive measurements of resulting signals received by a fourth group of the plurality of sensor electrodes,
• wherein acquiring second capacitive measurements comprises applying a second demodulation signal having a predefined second mixing period within a sensing period associated with the second sensing frequency, the second mixing period different than the first mixing period, and
• wherein the second mixing period is selected such that a second average current value for the second capacitive measurements has a substantially linear relation to a first average current value for the first capacitive measurements, the linear relation based on the first sensing frequency and the second sensing frequency.