An apparatus for combined
capacitance and
pressure sensing is described. The apparatus includes a
multiplexer (75) having a plurality of inputs (76) and an output (F), a
touch panel (29), and a front end module (3). The
touch panel includes a layer structure (5; FIG. 15) comprising one or more
layers, each extending perpendicularly to a thickness direction, the one or more
layers including a layer of piezoelectric material (10; FIG. 15), the layer structure having first (6) and second (7; FIG. 15) opposite faces, and the layer(s) arranged between the first and second faces such that the thickness direction of each layer is perpendicular to the first and second faces. The
touch panel also includes a plurality of first electrodes (8) disposed on the first face, each first
electrode connected to a respective input of the
multiplexer. The touch panel also includes at least one second
electrode (9) disposed on the second face. The front end module is configured to receive an input
signal (11) from the
multiplexer output. The front end module includes a first stage (12) configured to provide an amplified
signal based on the input
signal, and a second stage comprising first (13) and second (14) frequency-dependent filters configured to receive the amplified signal and to provide respective first (16) and second (17) filtered signals. The first filtered signal has a first frequency bandwidth, and the second filtered signal has a second frequency bandwidth which has a relatively higher start-frequency than the first frequency bandwidth.