Patent ID: 8228076

Claim:
A capacitance measuring system comprising: (a) analog-digital circuitry coupled to row conductors and column conductors of a touch screen panel for producing a first digital signal representative of cross-coupling capacitances of the touch screen panel, the analog-digital circuitry including row drive circuitry which superimposes charge transfers from cross-coupling capacitances of at least a plurality of the row conductors to a first column conductor to cause the first digital signal to be a convoluted signal which is a function of the cross-coupling capacitances of at least the plurality of row conductors; (b) calibration circuitry coupled to receive the first digital signal for subtracting base line data representing neutral values of the cross-coupling capacitances and subtracting the base line data from the first digital signal to produce a second digital signal which represents digital touch-induced capacitance change values caused by the presence of a touch near a cross-coupling capacitance of the touch screen panel; and (c) a deconvolution circuit for deconvoluting the second digital signal to produce a third digital signal which represents a magnitude map of the touch-induced capacitance change values.