A system includes a capacitively-coupled touch sensor having a conductive first layer and a conductive second layer on a first insulative layer. The width of the second layer varies along an axis of the first layer. A first excitation signal is applied to one of the first and second layers and is capacitively coupled through a touch element to the other layer, producing a first signal that produces a second signal which is digitized. Digitized peak values of the second signal are processed to compute a value for a touch element location. A conductive third layer can be placed on the opposite side of the first layer has width varying oppositely to the second layer. The first excitation signal is applied to the second layer and a non-overlapping second excitation signal is applied to the third layer. The resulting digitized peak values are processed to cancel errors due to variations.