Patent ID: 9696863
Date: 2017-07-04
CPC Classifications: G06F,H03K

Claim:
1. A touch screen device configured to determine positions of a plurality of input objects, the touch screen device comprising: a plurality of transmit electrodes disposed in a first direction in a sensing region of the touch screen device, a plurality of receive electrodes disposed in a second direction in the sensing region of the touch screen device, the second direction substantially orthogonal to the first direction, wherein the plurality of receive electrodes is fixed relative to the plurality of transmit electrodes, and wherein the plurality of transmit electrodes and the plurality of receive electrodes are configured for capacitive sensing; and a controller coupled to the plurality of transmit electrodes and the plurality of receive electrodes, the controller configured to: simultaneously apply a first modulation signal to a first transmit electrode of the plurality of transmit electrodes and a second modulation signal to a second transmit electrode of the plurality of transmit electrodes, wherein the first modulation signal comprises a carrier signal modulated according to a first distinct digital code of a plurality of distinct digital codes and the second modulation signal comprises the carrier signal modulated according to a second distinct digital code of the plurality of distinct digital codes, wherein the carrier signal has a periodically varying voltage; receive a plurality of resultant signals from the plurality of receive electrodes, wherein a first resultant signal of the plurality of resultant signals is received with a first receive electrode of the plurality of receive electrodes and a second resultant signal of the plurality of resultant signals is received with a second receive electrode of the plurality of receive electrodes, and wherein the first resultant signal comprises first electrical effects associated with at least the first modulation signal, and the second modulation signal and the second resultant signal comprises second electrical effects associated with at least the first modulation signal and the second modulation signal; demodulate the first resultant signal and the second resultant signal to obtain the first electrical effects and the second electrical effects by removing the carrier signal and then removing effects of the first distinct digital code and second distinct digital code; define a multi-dimensional image using at least the first electrical effects and the second electrical effects; determine the positions of the plurality of input objects at least partially based on the multi-dimensional image; and adjust a frequency of the carrier signal in response to electrical noise.