Patent ID: 8605054

Claim:
A touch screen system comprising: (a) a capacitive touch screen including a plurality of row conductors and a column conductor; (b) orthogonal drive circuitry coupled to simultaneously drive a plurality of cotemporaneous orthogonal excitation signals onto the row conductors, wherein the cotemporaneous orthogonal excitation signals occur over a plurality of successive time intervals each having a predetermined duration; and (c) receiver circuitry including (1) a sense amplifier coupled to generate an amplifier output signal in response to signals capacitively coupled onto the column conductor in response to the cotemporaneous orthogonal excitation signals on the row conductors, wherein one or more of the capacitively coupled signals on the column conductor may be influenced by a touch on the capacitive touch screen, and (2) logic circuitry for determining amounts of contribution of the cotemporaneous excitation signals to the amplifier output signal due to capacitive coupling from each row conductor, respectively, to the column conductor, wherein each of the cotemporaneous orthogonal excitation signals is generated by multiplying a plurality of segments of a carrier signal by a plurality of elements, respectively, of a corresponding Walsh-Hadamard sequence, wherein the capacitive touch screen includes a plurality of the column conductors and a plurality of the sense amplifiers each coupled to generate a corresponding amplifier output signal in response to signals capacitively coupled onto the plurality of column conductors in response to the cotemporaneous orthogonal excitation signals on the row conductors, wherein one or more of the capacitively coupled signals on the plurality of column conductors may be influenced by the touch on the capacitive touch screen, wherein the receiver circuitry includes a plurality of multiplier circuits for correlating the amplifier output signals by multiplying them by cotemporaneous orthogonal correlation signals, a plurality of summation circuits for accumulating correlated signal information from the multiplier circuits, respectively, over time intervals equal to the predetermined duration, and a plurality of sampling circuits for sampling outputs of the summation circuits, respectively, at ends of the successive time intervals, and wherein the logic circuitry determines amounts of signal contribution of the cotemporaneous excitation signals capacitively coupled from each row conductor, respectively, to each of the plurality of column conductors.