Patent ID: 11934612
Assignee: SYNAPTICS INCORPORATED
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 17:
18. A method for operating an input device, the method comprising:
coupling a sensing circuit to a first one of a plurality of electrodes disposed in a sensing region of the input device, the sensing circuit comprising an amplifier having an inverting input coupled to a first electrode of the plurality of electrodes;
applying a drive signal to a non-inverting input of the amplifier to thereby generate a resulting signal on an output of the amplifier, wherein the drive signal comprises a first sinusoidal signal having a first operating frequency and a second sinusoidal signal having a second operating frequency;
generating the resulting signal from a sensing signal on the first electrode,
wherein the resulting signal is determined by a capacitance of the first electrode and a feedback capacitor coupled between the output of the amplifier and the inverting input of the amplifier, and
wherein the capacitance of the first electrode is determined by a capacitance of an input object proximate the sensing region;
generating a plurality of output signals from the resulting signal,
selecting at least one output signal of the plurality of output signals is based on a comparison of a signal to noise ratio of each of the plurality of output signals with a noise threshold; the at least one output signal being selected according to the following criteria:
(a) based on none of the plurality of output signals being greater than the noise threshold, selecting each of the plurality of output signals,
(b) based on less than all the plurality of output signals being greater than the noise threshold, selecting one or more of the output signals that are greater than the noise threshold,
(c) based on all of the plurality of output signals being greater than the noise threshold, selecting an output signal having a lowest noise level, detecting the input object using the selected at least one output signal.