The device comprises a number P of single analogue inputs (2) for receiving each an analogue signal having a frequency F from a sensor electrode (3) and a single digital output (4) for sequentially generating a number P of first digital signals coding each an amplitude value of one analogue signal. The device comprises a multiplexer (5) with a number M of multiple analogue inputs (6) comprising each a number N of single analogue inputs for receiving each one analogue signal, with a multiple analogue output (7) comprising a number N of second single analogue outputs, a phase sensitive amplifier (9) with a number N of single analogue inputs (10) tied each to a second single analogue output of the multiplexer (5), with a number N of single analogue outputs (11), a multiplexer (13) with a number N of single analogue inputs (14) tied each to a single analogue output (11) of the phase sensitive amplifier (9), with a single analogue output (15) and an analogue digital converter (17) with a single analogue input (18) tied to the single analogue output (15) of the multiplexer (13), with a single digital output (20) tied to the output (4) of the device (1).