Patent ID: 8598894

Claim:
A method of measuring proximity of a body to a capacitive sensor device comprising a coupling capacitor having a capacitance sensitive to proximity of a body, and a charge accumulation capacitor having first and second plates, the first plate being connected to the coupling capacitor, and the second plate being connected to a voltage output line, the method comprising: making a signal measurement by transferring charge indicative of the capacitance of the coupling capacitor from the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure proximity of a body; and making a noise measurement by emulating the signal measurement, but inhibiting charge from arising on the coupling capacitor as a result of proximity of a body, thereby to transfer charge indicative of noise induced on the coupling capacitor to the charge accumulation capacitor, and by reading the voltage on the voltage output line, thereby to measure noise.