Patent ID: 9444452
Filing Date: 2016-09-13
CPC Classification: H03K

Claim Text:
1. A method, performed at a capacitance sensing system having a memory device and a controller coupled to the memory device, comprising: monitoring signals on a plurality of electrodes of a sense network at a plurality of operating frequencies; detecting a noise level on the plurality of electrodes at the plurality of operating frequencies; selecting one of the plurality of operating frequencies based on the detected noise level on the plurality of electrodes at the plurality of operating frequencies; using a noise detector to determine whether or not external noise is present; responsive to a determination that external noise is present, using a first filtering circuit of the controller to filter results of a scan of the plurality of electrodes at the selected one of the plurality of operating frequencies for localized noise events using the detected noise level corresponding to the selected one of the plurality of operating frequencies; and responsive to a determination that external noise is not present, using a second filtering circuit of the controller to filter results of the scan of the plurality of electrodes at the selected one of the plurality of operating frequencies for common mode noise using the detected noise level corresponding to the selected one of the plurality of operating frequencies.