The invention relates to a system for acquisition of biopotential signals, comprising at least a first electrode (E1) configured for detecting a biopotential signal within a signal bandwidth of interest and being connected to an impedance detection module (100) which provides a first electrode voltage (VO1) said impedance detection module (100) comprising a current generation circuit (40) connected in parallel to an amplifier (A1), the current generation circuit (40) comprising an AC current generator (AC1) configured to generate a first current signal (IS1) through said first electrode, said first current signal (IS1) having a frequency outside of the signal bandwidth of interest and a capacitor (CS1) connected between the input of the amplifier (A1) and the AC current generator (AC1) so as to isolate said AC current generator from said amplifier input at the signal bandwidth of interest and signal processing means (300) for calculating a component value (IMP) of a first and a second electrode-tissue impedance (Z1, Z2, ZB) based on the difference between the first electrode voltage (VO1) and a second electrode voltage (VO2 to VON BV).
