Systems, methods, and devices for capacitive sensing with sinusoidal demodulation

A method comprising:

• generating a transmit drive signal based, at least in part, on one or more scanning parameters, the transmit drive signal being provided to one or more transmit electrodes of a capacitive sensing device;
• generating, using a signal generator, a sinusoidal signal based, at least in part, on one or more noise characteristics of the transmit drive signal and capacitive sensing device;
• receiving a sensed signal from at least one sense electrode of the capacitive sensing device;
• reducing the one or more noise characteristics in the sensed signal based, at least in part, on the sinusoidal signal;
• and wherein the reducing comprises:
• combining, using a mixer, the sensed signal with the sinusoidal signal at an input of an attenuator.

A system comprising:

• a plurality of sense electrodes implemented in a capacitive sensing device;
• a plurality of transmit electrodes implemented in the capacitive sensing device;
• and an attenuator configured to receive an input from at least one of the plurality of sense electrodes, the attenuator being included in a sensing channel of a capacitive sensor;
• and a signal generator coupled to an input of the attenuator, the signal generator comprising one or more processors configured to:
• generate a sinusoidal signal based, at least in part, on one or more noise characteristics of a scan sequence associated with one or more transmit electrodes of the capacitive sensing device;
• provide the sinusoidal signal to the input of the attenuator;
• a controller configured to implement the scan sequence and obtain a plurality of measurements based on the scan sequence;
• and wherein the device further comprises:
• a mixer configured to combine the sinusoidal signal received from the signal generator and the input received from the at least one of the plurality of sense electrodes, and further configured to generate an output based on the combining.