Patent ID: 8730204
Filing Date: 2014-05-20
Classification: G06F

Abstract:
1. A processing system for an input device, the processing system comprising: a sensor module comprising sensor circuitry, the sensor module configured to transmit a first transmitter signal with a transmitter electrode and receive a resulting signal with a receiver electrode, wherein the first transmitter signal comprises a first transmitter frequency, and the resulting signal comprises effects corresponding to the first transmitter signal; and a demodulation module configured to demodulate the resulting signal to produce first and second output signals, the demodulation module comprising: a first mixing stage comprising a first mixing frequency and a second mixing frequency; and a second mixing stage in series with the first mixing stage and comprising a third mixing frequency and a fourth mixing frequency; wherein the third mixing frequency is a combination of the first mixing frequency and the first transmitter frequency; and wherein the demodulation module is configured to determine a first measurement of a change of capacitive coupling between the transmitter electrode and the receiver electrode based on the first output signal, and to determine positional information for an input object based on the first measurement.