The invention concerns apparatus for processing signals induced by a stylus applied to a digitizing tablet. The tablet produces four signals, A, B, C, and D, indicative of four currents, induced at four different points on the tablet, by the stylus. The four signals indicate the position of the stylus....http://www.google.fr/patents/US5945639?utm_source=gb-gplus-shareBrevet US5945639 - Cancellation of common-mode signals in digitizing tablet
Cancellation of common-mode signals in digitizing tablet
