Patent ID: 8890840

Claim:
A method for detecting capacitance values of a plurality of capacitive sensing nodes located at intersections of a plurality of drive lines and a sense line on a touch panel, comprising: obtaining a plurality of touch sense signals corresponding to the sense line during a plurality of time slots, respectively; demodulating the touch sense signals with a first oscillation signal to generate a plurality of first demodulated signals; demodulating the touch sense signals with a second oscillation signal to generate a plurality of second demodulated signals, wherein the second oscillation signal is different from the first oscillation signal; and determining the capacitance values according to at least the first demodulated signals and the second demodulated signals; wherein each touch sense signal is obtained when the drive lines are simultaneously driven by a plurality of stimulation signals; during the time slots, stimulation signals are generated according to a common modulation carrier and a plurality of sign values defined in an encoding matrix; and the step of determining the capacitance values according to at least the first demodulated signals and the second demodulated signals comprises: performing matrix multiplication according to a decoding matrix and the first demodulated signals, and accordingly generating a plurality of first matrix elements, wherein the decoding matrix is an inverse of the encoding matrix; performing matrix multiplication according to the decoding matrix and the second demodulated signals, and accordingly generating a plurality of second matrix elements; and determining each capacitance value by calculating a root sum square (RSS) value of each pair of one first matrix element and one second matrix element.