Synaptics Incorporated
Sensing device with embedded noise measurement

Abstract:

A processing system and method are provided. The processing system includes a sensor circuit that drives, during a first sensing period, a first plurality of sensor electrodes with first sensing signals, receives first resulting signals from the first plurality of sensor electrodes, and mixes the first resulting signals with a first mixer signal to generate a first mixed signal, wherein the first mixer signal has a first phase and the first mixed signal corresponds to at least a portion of a capacitive image. The processing system also includes a noise measurement circuit that receives second resulting signals from a second plurality of sensor electrodes, and mixes the second resulting signals with a second mixer signal to generate a second mixed signal, wherein the second mixer signal has a second phase and the second mixed signal corresponds to a first noise measurement.