Touch-sensitive interface and method using orthogonal signaling

A method for operating a touch screen system including

• a capacitive touch screen including a plurality of row conductors and a column conductor, and
• receiver circuitry including a sense amplifier coupled to generate an amplifier output signal in response to signals capacitively coupled onto the column conductor,
• the method comprising:
• (a) simultaneously driving a plurality of cotemporaneous orthogonal excitation signals onto the row conductors, respectively, 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 wherein the cotemporaneous orthogonal excitation signals occur over a common plurality of successive time intervals, each of the successive time intervals having a predetermined duration;
• and
• (b) determining amounts of contribution by each of the cotemporaneous excitation signals to the amplifier output signal due to capacitive coupling from each row conductor, respectively, to the column conductor.

A touch screen system comprising:

• (a) a capacitive touch screen including a plurality of row conductors and a column conductor;
• (b) receiver circuitry including a sense amplifier coupled to generate an amplifier output signal in response to signals capacitively coupled onto the column conductor;
• (c) means for simultaneously driving a plurality of cotemporaneous orthogonal excitation signals onto the row conductors, respectively, 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 wherein the cotemporaneous orthogonal excitation signals occur over a common plurality of successive time intervals, each of the time intervals having a predetermined duration;
• and
• (d) means for determining amounts of signal contribution by each of the cotemporaneous excitation signals to the amplifier output signal due to capacitive coupling from each row conductor, respectively, to the column conductor.