METHODS AND SYSTEMS FOR DETECTING A POSITION-BASED ATTRIBUTE OF AN OBJECT USING DIGITAL CODES

摘要

Methods, systems and devices are described for detecting a position-based attribute of a finger, stylus or other object with a touchpad or other sensor having a touch-sensitive region that includes a plurality of electrodes. Modulation signals for one or more electrodes are produced as a function of any number of distinct digital codes. The modulation signals are applied to an associated at least one of the plurality of electrodes to obtain a resultant signal that is electrically affected by the position of the object. The resultant signal is demodulated using the plurality of distinct digital codes to discriminate electrical effects produced by the object. The position-based attribute of the object is then determined with respect to the plurality of electrodes from the electrical effects.

主权项

1. A controller for a capacitive position sensor, the controller comprising:
drive circuitry configured to simultaneously transmit a first signal with a first transmitter electrode and a second signal with a second transmitter electrode, wherein the first and second signals are distinct signals based on distinct digital codes; and receiver circuitry configured to receive resultant signals with a plurality of receiver electrodes proximate to and capacitively coupled with the first transmitter electrode and the second transmitter electrode; wherein the controller is configured to adjust a frequency of the first and second signals based on observed noise in the resultant signals.